Audio Audio algemeen How to make Audacity work with ALSA How to make Audacity work with ALSA If you want to work with the audio editing software Audacity, and you get an error starting Audacity, you can try the following: start audacity with the following command: >aoss audacity This will start audacity with the alsa osscompatibility layer. or try selecting in Preferences ALSA Default as the sound device How to make MP3 support working sudo ln -s /usr/lib/libmp3lame.so.0 /usr/lib/libmp3lame.so Sound (Audacity) How to make Audacity work with ALSA Normalize audio Play audacity over network Radiostation URLs xine http://217.196.35.12/asx/radioveronica.asx http://listen.soulradio.com/soulradio.pls http://listen.soulradio.com/soulradio.m3u Quadrophonic or DTS surround sound qoute: Some of my favorite quadraphonic titles: Sound effects with Boeing 707 and 727 takeoff and landings. Pink Floyd – Dark Side Of The Moon The Moody Blues – Days Of Future Passed The Moody Blues – Every Good Boy Deserves A Favor The Moody Blues – Seventh Sojourn Edger Winter Group – They Only Come Out At Night The Doobie Brothers – The Captain & Me The Doobie Brothers – Toulouse Street Earth Wind & Fire – That’s The Way Of The World Earth Wind & Fire – Open Our Eyes Ohio Players – Honey Quincy Jones – You’ve Got It Bad Girl Burt Bacharach – Reach Out The Carpenters – A Song For You The Carpenters – Close To You Steely Dan – Countdown To Ecstasy Deep Purple – Machine Head Black Sabbath – Paranoid Chick Corea & Return To Forever – Musicmagic Sergio Mendes – (self title) Jeff Beck – Blow By Blow Maynard Ferguson - Conquistador Enoch Light – Sounds of Burt Bacharach I still have these but it's been years since I played them. Still have a SQ decoder laying around too. ALLMAN BROTHERS EAT A PEACH BAEZ, JOAN BLESSED ARE BAEZ, JOAN FROM THE SHADOWS BAEZ, JOAN GREATEST HITS AND MORE BENSON, GEORGE BODY TALK BERNSTEIN-NYP ALSO SPRAC ZARASTRUSA BERNSTEIN-NYP HIGHLIGHTS FROM MASS BERNSTEIN-NYP MASS BLACK SABBATH PARANOID BLOOD, SWEAT AND TEARS BLOOD, SWEAT & TEARS BLOOD, SWEAT AND TEARS GREATEST HITS BLOOD, SWEAT AND TEARS NEW BLOOD CARLOS, WALTER SWITCHED ON BACH CARPENTERS THE SINGLES CHASE CHASE CORYELL, LARRY OFFERINGS CORYELL, LARRY INTRODUCTING THE ELEVENTH HOUSE COUNTRY JOE & THE FISH THE LIFE AND TIMES OF DAVIS, MILES BITCHES BREW DAVIS, MILES LIVE EVIL DEEP PURPLE MACHINE HEAD DEEP PURPLE STORMBRINGER DEODATO DERRINGER, RICK ALL AMERICAN BOY DERRINGER, RICK RICK DERRINGER DOORS THE BEST OF THE DOORS DYLAN, BOB NASHVILLE SKYLINE DYLAN, BOB DESIRE DYLAN, BOB PLANET WAVES GRASSROOTS SIXTEEN GREATEST HITS EARTH, WIND AND FIRE THE WAY OF THE WORLD HANCOCK, HERBIE HEADHUNTERS JEFFERSON AIRPLANE VOLUNTEERS JETHRO TULL AQUALUNG JETHRO TULL WAR CHILD JOPLIN, JANIS PEARL KING, BB FRIENDS KING, CAROLE MUSIC KOOPER,BLOOMFIELD,STILLS SUPERSESSION KRISOFFERSON, KRIS THE SILVER TONGUE DEVIL KRISOFFERSON, KRIS BORDER LORD KRISOFFERSON, KRIS JESUS WAS A CAPRICORN LOGGINS AND MESSINA LOGGINS AND MESSINA LOGGINS AND MESSINA FULL SAIL MAHAVISNU ORCHESTRA BIRDS OF FIRE MAHAVISNU ORCHESTRA FROM NOTHINGNESS TO ETERN MASON, DAVE DAVE MASON MASON, DAVE IT'S LIKE YOU NEVER LEFT MASON, DAVE SPLIT COCONUTS MILES, BUDDY CHAPTER VIII MOTT THE HOOPLE THE HOOPLE MOUNTAIN THE BEST OF MOUNTAIN AVALANCHE WEST,BRUCE AND LAING WHY DONCHA WEST,BRUCE AND LAING WHAT EVER TURNS YOU ON NEKTAR REMEMBER THE FUTURE NEKTAR DOWN TO EARTH NEW RIDER OF THE PURPLE SAGE PANAMA RED OLDFIELD, MIKE BOXED (TUBULAR BELLS, HEREST RIDGE, OMMADAWN) OLDFIELD, MIKE EXPOSED PINK FLOYD ATOM HEART MOTHER PINK FLOYD DARK SIDE OF THE MOON PINK FLOYD WISH YOU WERE HERE POCO DELIVERIN' POCO SEVEN POCO CANTANMOS REDBONE MESSAGE TO THE NATION REO SPEEDWAGON PAUL REVERE & THE RAIDERS INDIAN RESERVATION SANTANA ABRAXIS SANTANA III SANTANA AND BUDDY MILES CARLOS SANTANA AND BUDDY MILES SANTANA CARAVANSERI SANTANA LOTUS SANTANA WELCOME SANTANA BORBOLETTO SANTANA & McLAUGHLIN LOVE DEVOTION & SURRENDER SANTANA & ALICE COLTRANE INNERVISIONS SANTANA BEST OF GARFUNKEL, ART ANGEL CLAIRE GARFUNKEL, ART BREAKAWAY SLY AND THE FAMILY STONE GREATEST HITS SLY AND THE FAMILY STONE SMALL TALK STEVENS, CAT FOREIGNER STREISAND, BARBARA STONEY END STREISAND, BARBARA LIVE AT THE FORMUN STREISAND, BARBARA BARBARA JOAN STRIESAND STREISAND, BARBARA LAZY AFTERNOON SUBOTNIC, MORTON TOUCH TEN YEARS AFTER A SPACE IN TIME THREE DOG NIGHT HARD LABOR THREE DOG NIGHT VAN LEER, THIJS INTROSPECTION VAN LEER, THIJS INTROSPECTION 2 WAKEMAN, RICK THE SIX WIVES OF HENRY THE VIII WAKEMAN, RICK THE SIX WIVES OF HENRY THE VIII WALSH, JOE SMOKER YOU DRINK THE PLAYER YOU GET WEATHER REPORT MYSTERIOUS TRAVELER WEATHER REPORT TALE SPINNING WINTER, EDGAR THEY ONLY COME OUT AT NIGHT WINTER, EDGAR SHOCK TREATMENT WINTER, JOHNNY STILL ALIVE AND WELL WINTER, JOHNNY SAINT AND SINNER WINTER, JOHNNY JOHN DAWSON WINTER III ZAPPA, FRANK OVERNIGHT SENSATION ZAPPA, FRANK APOSTRIE Normalize audio NORMALIZE # zypper in normalize SYNOPSIS normalize [ options ] [ -- ] file ... First, make a copy of the file. Then do one of the following: # normalize test.wav normalizes at -15 dB ??? # normalize -a Adjust the RMS volume to the target amplitude AMPLITUDE; must be between 0.0 and 1.0. If a number suffixed by "dB" or "dBFS" is specified, the amplitude is assumed to be in decibels from full scale. The default is -12dBFS. # normalize -b BATCH MODE When operating on a group of unrelated files, you usually want all of them at the same level, and this is the default behavior. However, a group of music files all from the same album is generally meant to be listened to at the relative volumes they were recorded at. In batch mode, all the specified files are considered to be part of a single album and their relative volumes are preserved. This is done by averaging the volumes of all the files, computing a single adjustment from that, and applying the same adjustment to all the files. Some analysis is also done so that files with volumes that appear to be statistical aberrations are not considered in the average. This is useful if you have albums (like many of the author's) in which there is one "quiet song" that throws off the average. # normalize -m, --mix Enable mix mode: see MIX MODE, below. Batch mode and mix mode are mutually exclusive. This mode is made especially for making mixed CD's and the like. You want every song on the mix to be the same volume, but it doesn't matter if they are the same volume as the songs on some other mix you made last week. In mix mode, average level of all the files is computed, and each file is separately normalized to this average volume. # normalize -n  Compute and output the volume adjustment that would set the volume to the target, but don't apply it to any of the files (i.e. skip the second phase). If you use this option, your files will not be altered in any way. # normalize --peak Adjust using peak levels instead of RMS levels. Each file will be adjusted so that its maximum sample is at full scale. This just gives a file the maximum volume possible without clipping; no normalization is done. # normalize -v Increase verbosity. This option can be repeated for more messages. -- end of options FFMPEG Detect RMS level # ffmpeg -i inputfile.flac -filter:A volumedetect -f null /dev/null  ... [Parsed_volumedetect_0 @ 0x562a0076b200] n_samples: 23664648 [Parsed_volumedetect_0 @ 0x562a0076b200] mean_volume: -12.6 dB [Parsed_volumedetect_0 @ 0x562a0076b200] max_volume: 0.0 dB [Parsed_volumedetect_0 @ 0x562a0076b200] histogram_0db: 24907 eventueel: # for i in *; do ffmpeg -i "$i" -filter:a volumedetect -f null /dev/null 2>&1 | grep mean; done normalize to LUFS standard # ffmpeg -i videofile.mp4 -af loudnorm=I=-24:LRA=11:TP=-1 -b:a 160k output-lufs.mp3 # for i in *; do ffmpeg -i "$i" -af loudnorm=I=-24:LRA=11:TP=-1 -b:a 160k "$i"-lufs.mp3; done where I = integrated loudness LRA = loudness range TP = true peak to normalize audio from mp4 video files in parallel # ls -U *.mp4 | parallel -j6 ffmpeg -i {} -af loudnorm=I=-24:LRA=11:TP=-1 -b:a 160k {/.}-lufs.mp3 Tune the parameter j6 to your #cores. This is faster than -threads 0 parameter, which is supposed to use all cores but doesn't. SOX # sox inputfile.flac -n stat # sox inputfile.flac -n stats Overall Left Right DC offset 0.000638 0.000397 0.000638  Min level -0.773560 -0.773560 -0.773560 Max level 0.773529 0.773529 0.773529 Pk lev dB -2.23 -2.23 -2.23 RMS lev dB -14.84 -15.28 -14.43 RMS Pk dB -8.71 -10.03 -8.71  RMS Tr dB -inf -inf -inf Crest factor - 4.49 4.07 Flat factor 1.74 2.13 1.58 Pk count 131 72 190 Bit-depth 16/16 16/16 16/16 Num samples 11.8M Length s 268.307 Scale max 1.000000 Window s 0.050 Audio Revox B215 installing audio plugins Use yt-dlp the correct way for music files Use yt-dlp with subtitles for video files Use METAFLAC to edit Flac Tags use NAB test tape to calibrate IEC deck and vice versa pulseaudio settings for audiophiles Otari Mx-55 N-M 24bit vs 16bit, the myth exploded! Athana PF-212 Bulk Eraser cm6631a check soundcard settings: bitrate vlc tips & tricks lagers jazz DCC chips DCC FAQ DCC history DCC tapes Philips DCC170 Philips DCC600 Philips DCC900 Philips DCC951 Philips FW68 Technics RS-BX501 Technics SL-P777 BASF tape formulas BASF Cassette history Doormeten van een transistor My setup Quadrophonic or DTS surround sound muziek verlanglijstje Teac A-3440 Tascam history Studer A80 history Dolby NR dbx de dB Reel to reel tapes info cleaning contacts - contact spray knosti liquid DVDA authoring Reference Tapes - Calibration plakkende tapes afspelen identificatie van reel to reel tapes aan de hand van de aanloopstrook tape reference level Flux Level Standards Revox PR99 reference level Revox PR99 history Velleman PCSGU250 Degaussing NAB vs. IEC Technics 1500 - 1700 De dB De dB Auteur: Hans Beekhuyzen Als je je met audio en video bezighoudt, kan je niet om de decibel oftewel dB heen. Toch zorgt de dB nog wel eens voor verwarring, dus is het tijd voor een uitleg.. In de begintijd van de telefoon was in Amerika Bell Company aan het onderzoeken hoe groot (telefoon-)lijnverliezen waren. Men ontdekte dat als je lijnverliezen uitdrukte in vermogensverlies, dus in watts, er weinig relatie was met de gehoormatige ervaring van het verlies. Dus heeft men een eenheid ontwikkeld die dat wel had: de Bel. Eén Bel toename werd gedefinieerd als een verdubbeling van waargenomen luidheid. Daarvoor bleek een tienvoudige vermogen voor nodig te zijn. In de begintijd was dat best een probleem, want het hele systeem werkte zonder versterking. Als je meer signaal wilde, dan moest je gewoon harder schreeuwen. En om een zo hoog mogelijk rendement te krijgen, werden de impedanties van microfoon (zender) en luidspreker (ontvanger) op elkaar aangepast om zoveel mogelijk vermogen door de leiding te krijgen. Dit concept van gelijke impedanties aan zend- en ontvangstkant - de zogenaamde stroomaanpassing - werd later overgenomen door omroepen; het zogenaamde 600 ohm systeem. En ook thuis was er vaak sprake van impedantieaanpassing. Want omdat buizenversterkers relatief hoogohmig uit gaan in vergelijking met een luidspreker, wordt een uitgangstransformator gebruikt die ook weer voor een optimale impedantieaanpassing aan beide kanten zorgt. Bel luiden Maar terug naar de dB; zoals gezegd spreek je van 1 Bel als het geluid twee keer zo hard klinkt en daarvoor is tien keer zoveel vermogen nodig. Even een staatje: 0 Bel = 1 W
 - referentieniveau 1 Bel = 10 W
 - twee keer zo hard 2 Bel = 100 W - drie keer zou hard 3 Bel = 1000 W - vier keer zo hard Het leuke is dat het aantal nullen in het vermogen het getal in Bel aangeeft. Wiskundigen noemen dat logaritme en je schrijf het zo: 0 Bel = 1 x 1 = 1 W (referentieniveau) 1 Bel = 1 x 10¹ = 10 W (klinkt +1 keer harder) 2 Bel = 1 x 10² = 100 W (klinkt +2 keer harder) 3 Bel = 1 x 10³ = 1000 W (klinkt +3 keer harder) Het logaritme van een getal is de exponent (het kleine cijfertje) van een basisgetal (bij dB’s altijd 10). Maar maak je er niet te sappel om; als je het concept begrijpt dan kan elke zakjapanner het rekenwerk doen. De formule is: Om de formule uit te rekenen deel je eerst de ene vermogenswaarde door de andere, drukt op de log knop van de rekenmachine. Reken het verschil tussen 2 W en 15 W maar eens uit: Deel 15 door 2 (of andersom), je krijgt 7,5 als uitkomst. Druk op de log knop en controleer de uitkomst: 0,87506..... oftewel 0,875 Bel. Al snel bleek dat de Bel een veel te grove maat was, dus ging men werken met tienden van een Bel: de decibel. Dat is ook meteen ongeveer het kleinste niveauverschil dat we met ons gehoor kunnen waarnemen bij ongewijzigde klankbalans. Dat betekent dus dat 10 dB twee keer zo hard klinkt en dat daar 10 keer zoveel vermogen voor nodig is. De formule is natuurlijk gelijk aan die van de Bel, alleen wordt nu de uitkomst met 10 vermenigvuldigd: Spanning en sensatie Hiervoor had ik het er al over dat er zo min mogelijk vermogen verloren gaat als er een optimale impedantieaanpassing is. Maar tegenwoordig gebruiken we zelden nog impedantieaanpassingen in analoge audio. Het is nu niet meer nodig om het vermogen van de bron zo effectief mogelijk over te brengen omdat het veel eenvoudiger is op de juiste plekken versterking toe te passen. Het enige wat we willen is een zo goed mogelijke representatie van het audiosignaal en dat kan ook met spanning. Zolang je zorgt dat de ingangsimpedantie van het ontvangende apparaat minimaal tien keer zo groot is als de uitgangsimpedantie van het zendende apparaat, is de stroom redelijk beperkt en geeft de spanning een prima ‘plaatje' van het signaal. Maar dat heeft wel gevolgen voor het rekenen in dB's want vermogen is de spanning in het kwadraat gedeeld door de impedantie: Als we nu de dB formule aanpassen voor spanning, krijgen we: De eerste formule is zoals we hem kennen voor vermogen. Aangezien we spanning willen berekenen, vervangen we het symbool voor vermogen (P) door de formule en zien we de tweede stap. In de derde stap hebben we in de deling de weerstand verwijderd omdat we aannemen dat die in beide gevallen gelijk is (dat mag omdat bijvoorbeeld 600 ohm gedeeld door 600 Ohm 1 is). In de vierde stap hebben we het kwadraat van beide U's buiten de haakjes gehaald en in de vijfde stap verhuist die tweede macht naar het begin van de formule en omdat we daar aan de andere kant van de logaritmeberekening zijn (dus in het exponent van 10 rekenen), mogen we de 2 met de 10 vermenigvuldigen. Als we het dus over stroom hebben, dan is de formule: terwijl bij spanning de volgende formule geldt: Ok, we kunnen nu dB's berekenen dus iedereen weet wat 12 dB is? Nee dus. Want de dB is een verhoudingsmaat, zoals uit de deling in de formule ook valt af te leiden. Je kunt alleen maar verschillen uitrekenen en geen absolute waarden. Maar +4 dB was toch 1,22 V, het pro lijnniveau in de studio? Nee, want er is niet aangegeven ten opzichte van welke andere spanning gerekend is. Gelukkig is dat ook gestandaardiseerd, waardoor we de dB als quasi-absolute waarde kunnen gebruiken. dBm Als we teruggaan naar de begintijd van de omroep, dan zien we stroomaanpassingen op transformatorgebalanceerde 600 Ohm lijnen. Men bepaalde dat 1 milliwatt over 600 Ohm als algemene referentie werd genomen en noemde dat de dBm. De dBm is dus een vermogensverhouding met als referentie 1 mW over 600 Ohm. Nu wordt vermogen gemeten door een spanningsval over een bekende weerstand te meten en terug te rekenen naar vermogen met de eerder genoemde formule. In het geval van 0 dBm meet je 0,775 V spanningsval over een 600 Ohm weerstand. Wederom vereenvoudigd geeft dit de volgende formule: Maar omdat in de audiotechniek nog maar zelden gebruik wordt gemaakt van een stroomaanpassing, wordt de dBm nog maar zelden gebruikt. Maar het heeft wel zijn gevolgen gehad voor de toekomst, want in die situatie moesten volgens de NAB (North American Broacaster) VU-meters worden afgeregeld op +4 VU om te compenseren voor de traagheid van de VU -meter. +4 VU Boven 0 dBm komt overeenkomt met een spanningsval van 1,22 V over 600 Ohm. En daar is die 1,22 V weer! dBu Maar men bleef wel die 0,775 V als 0 dB referentie houden, ook in spanningsaanpassingen. Vooral in de tijd dat beide manieren naast elkaar werden gebruikt, was dat natuurlijk ook het handigst. Maar om aan te geven dat het nu alleen om spanning ging, werd de dBu (met de kleine u van spanning) uitgevonden. Dit is dus wel een spanningsverhouding en wordt dus uitgerekend met de formule: dBV Ondertussen ontstond er een logischer norm die 1V aanhoudt als referentie, de dBV, waarbij de grote V natuurlijk staat voor Volt. Ook hier hebben we het weer over een spanningsverhouding, dus geldt als formule: dBFS Met de komst van digitale apparatuur kwam er behoefte aan een digitale variant. Daarbij werd uitgegaan van het maximaal te registreren signaal, dus waarbij alle bits 1 zijn. Voor een 16-bits systeem ziet dat er als volgt uit: Je kunt het natuurlijk de binaire waarde omzetten in een decimale en je rekenwerk doen. Er zullen echter niet zoveel mensen zijn die zo werken, dus is het gebruikelijk de op het betreffende apparaat de voor 0 dBFS benodigde of afgegeven spanning als referentie te nemen. Veel cd-spelers geven 2V af bij 0 dBFS. Dus als je met zo'n cd-speler zonder signaal een spanning van 0,00004 V meet, dan heb je een signaal/ruisafstand van -93,97 dBFS. Reken het maar na. Nu kun je dus elke verhouding met dB's uitrekenen. Als je dit jaar € 60.000 hebt verdiend en vorig jaar € 56.400, hoeveel dB heb je dan meer verdiend. Wel dat hangt af of het om vermogen of spanning gaat! Een beetje een flauw grapje, maar het is een feit dat alles zich laat vertalen in verhoudingen en als die logaritmisch weergegeven meer zeggen dan lineair, dan is de dB een prima maat. Zo kun je uitrekenen wat de verschillen in signaal/ruisverhouding zijn tussen de diverse analoge bandrecorderkoppen. Amateurrecorders als van Revox en Teac gebruik(t)en bij tweespoorskoppen spoorbreedten van 2 mm terwijl Amerikaanse recorders als die van Ampex sporen van 2,4 mm breedte gebruikten. Dat scheelt meteen 1,6 dB aan signaal/ruisafstand. Europese recorders als van Studer en Telefunken konden uitgerust worden met zogenaamde vlinderkoppen en die schreven sporen van 2,7 mm hetgeen een signaal/ruisafstandsverbetering geeft van 2,6 dB ten opzichte van de amateurrecorder en 1 dB ten opzichte van Amerikaanse professionele recorders. dB SPL Ook geluidsniveau's kunnen met dB's gemeten worden en dat gebeurt ook. De bekendste is de dB SPL, decibel sound pressure level. Het referentieniveau is hier natuurlijk geluidsdruk en wel 0,0002 microbar en omdat het om een niveau gaat, gebruiken we de formule die ook voor spanning wordt gebruikt (je zou kunnen zeggen dat je het over membraanspanning hebt). Rest mij af te sluiten met een leuk voorbeeld over de misverstanden die de dB kan veroorzaken: enkele jaren geleden stond een stukje in een krant waarin een horeca-uitbater uit het Oosten des Lands was bekeurd voor het overtreden van de hinderwet met 12 dB. Volledig overtuigd van de onzin hiervan zij hij tegen de reporter: "Het was maar 12 dB te hard. Ik heb het opgezocht en 12 dB komt overeen met het geluid van een vallende speld." Hij vond dat hij dus maar het geluid van een vallende speld te hard had gedraaid. Ga daar maar eens tegenin. Cleaning contacts - contact spray ENGLISH BELOW HERSTELLING VAN CONTACTEN - PROFESSIONELE REINIGING EN ONDERHOUD VAN CONTACTEN De optimale herstelling van elektrische contacten in 3 stappen. Snel Betrouwbaar Economisch STAP 1 KONTAKT 60 Lost corrosielagen op en herstelt het metaalcontact. Ter voorkoming van het risico dat na een bepaalde tijd corrosie optreedt, is het aanbevolen stap 2 en 3 te volgen. STAP 2 KONTAKT WL Verwijdert opgeloste corrosieproducten, vet en vuil. STAP 3 KONTAKT 61 Vormt een dunne beschermende film die corrosie en slijtage voorkomt. Verdere op- en aanmerkingen Veel contactsprays laten een olie achtige film achter welke beschermt tegen vocht en corrosie. Echter trekt deze laag ook weer vuil en stof aan wat juist weer voor kraken en storen kan zorgen in audio. Ik adviseer sprays van Kontakt Chemie, en dan de Contact WL. Deze contactspray spoelt vuil weg en verdampt volledig, dus laat ook niets achter. Een idee is om deze spray royaal op en tussen je potmeters los te laten, zodat het er werkelijk uitloopt en draai gedurende deze behandeling de potmeters een paar keer heen en weer. Herhaal dit een paar keer zodat de residues van de oude contactspray goed worden weggespoeld. Ga er eventueel achter aan met perslucht om het geheel goed droog te blazen en fohn het verhaal eventueel warm. Perslucht bevat immers altijd vocht en dat wil je ook niet in je potmeters hebben. De volgorde is 60-WL-61 (inplaats van WL gebruikt men soms IPA, werkt ook goed). Alleen Kontakt 60 gebruiken is niet voldoende en zal de contacten uiteindelijk aantasten (is licht zuur) en problemen veroorzaken in HF-schakelingen (diëlectrisch en enigszins geleidend) En gebruik voor potmeters geen Kontakt 60, dat vreet de ingewanden op. Gebruik Contact Cleaner 390 of Kontakt Tuner spray. Tuner 600 (kontakt chemie) spray is prima deze verdampt volledig en laat geen residu achter, maar smeert ook niet, en of dat in een potmeter of schakelaar echt goed is? Vandaar het rijtje 60-WL-61 of 60-IPA-61. 390 is op basis van een Philipsrecept en zou "alles in 1" moeten zijn, maar de details ken ik niet. Gezien de reputatie op gebied van research en doordachte spullen (dit bedoel ik niet cynisch) die Philips had, zou het toch goed spul moeten zijn. Reden dat 60 bij metalen contacten vaak nodig is, is dat dit oxidelaagjes het effectiefst oplost (juist omdat het licht zuur is, werkzame stof is oliezuur als ik goed geïnformeerd ben). Tuner 600 zal goed reinigen, maar wat het met oxides doet weet ik niet. Zelf gebruik ik altijd Tuner600 om faders/potmeters te reinigen, als ze maar licht vervuild zijn tenminste. Werkt prima. Voor zware vervuiling, lukt het met Tuner600 niet. Uit elkaar halen is nog altijd het best idd. ENGLISH - Treatment of bad contacts - professional cleaning and maintenance of contacts 3 steps: step 1 Kontakt 60. Dissolves corrosion layers and restores metal contact. To avoid the risk of corrosion occurring after a certain period of time, it is recommended to follow steps 2 and 3. step2 KONTAKT WL Removes dissolved corrosion products, grease and dirt. step3 Kontak 61 This forms a thin protective film that prevents corrosion and wear. =Further notes:= Many contact sprays leave an oily film that protects against moisture and corrosion. However, this layer also attracts dirt and dust, which in turn can cause cracking and disturbance in audio. I recommend sprays from Kontakt Chemie, and then the Contact WL. This contact spray washes away dirt and completely evaporates, so it also leaves nothing behind. An idea is to liberally release this spray on and between your potentiometers, so that it really runs out and during this treatment turn the potentiometers back and forth a few times. Repeat this a few times so that the residues of the old contact spray are rinsed well. If necessary, go after it with compressed air to blow it completely dry and blow-dry the story if necessary. After all, compressed air always contains moisture and you don't want that in your pot meters. The order is 60-WL-61 (instead of WL one sometimes uses IPA, works well too). Using only Contact 60 is not sufficient and will eventually attack the contacts (is slightly acidic) and cause problems in HF circuits (dielectric and slightly conductive) 'And don't use Kontakt 60 for potentiometers, that will eat the guts. Use Contact Cleaner 390 or Kontakt Tuner spray. ' Tuner 600 (contact chemistry) spray is fine, it completely evaporates and leaves no residue, but does not lubricate, and whether that is really good in a potentiometer or switch? Hence the list 60-WL-61 or 60-IPA-61. 390 is based on a Philips recipe and should be "all in 1", but I don't know the details. Given the reputation for research and thoughtful stuff (I don't mean this cynically) that Philips had, it should be good stuff. The reason that 60 is often required for metal contacts is that these dissolve oxide layers most effectively (precisely because it is slightly acidic, the active substance is oleic acid if I am well informed). Tuner 600 will clean well, but I don't know what it does with oxides. I always use Tuner600 to clean faders / potentiometers, as long as they are slightly dirty. Works fine. For heavy pollution, Tuner600 does not work. Disassembly is still best. Amplifier JVC MCA-V7 JVC_MCA_V7E.jpg Around early 1970 (japanses translation) Commentary 4ch Amplifier equipped with a Sound Field Composer. I am equipped with a Sound Field Composer circuit where you can enjoy the atmosphere of 4ch in 2ch source. By a device to reproduce the pseudo 4ch, is output from the speakers of another reverberation only component that is included in the 2ch source, this circuit is aimed to reproduce the sense of reality. It uses a 2ch-4ch complementary circuit by BTL Type of actuation in the MCA-V7, to drive each speaker in the SEPP circuit four sets 4ch playback, I get a high-powered by BTL connection 2ch time. I have adopted a quasi-complementary ITL · OTL circuit to circuit configuration. In addition, with the aim of noise reduction by adopting a low-noise silicon transistor. Equalizer circuit has become a two-stage, and is stopping the transistor noise by using a PNP transistor in the first stage. 4ch and two inputs, it is equipped with the 4ch recording and playback terminal. It is equipped with an pre-out main-in terminal of 4ch, it can be used independently of the main amplifier and preamplifier. Model 4ch Amplifier Circuit system SEPP-OTL circuit, BTL switchable Music Power 45W +45 W (8Ω) Effective output 12.5W × 4 (8ohms) 28W +28 W (8ohms) Harmonic distortion 0.08% (12.5W) Intermodulation distortion 0.2% (12.5W) Power Band Width 30Hz ~ 50kHz-3dB Frequency characteristic 20Hz ~ 100kHz ± 0.5dB SN ratio 90dB or more Input sensitivity / impedance 0.6V/50kΩ Load impedance 8Ω ~ 16Ω Damping factor 50 (8Ω) Input sensitivity / impedance Phono: 3MV/50keiomega Tuner, Aux, Tape play, DIN: 50MV/100keiomega Phono maximum permissible input 100mV Tone control 4ch tone control, NF type Bass: ± 10 dB (100 Hz) Treble: ± 10 dB (10 kHz) Output Impedance Pre out: 0.5V (nominal), 5V (maximum) / 1.2 kW Rec out: 36MV/4.7Keiomega DIN: 36MV/80keiomega Frequency characteristic Phono: RIAA ± 0.5 within 20Hz ~ 40kHz +0-1.5dB: Aux Harmonic distortion 0.1% (1kHz, 2.5V) Intermodulation distortion (60Hz: 70kHz = 4:1) 0.2% (2.5V) SN ratio (IHF) Phono: 80dB Aux: 85dB Input terminal Phono, Tuner, Aux, Tape play, 4CH Aux, 4CH Disc, Main in Output terminal Pre out, Rec out, SP out DIN terminal 1 system Attached circuit Tape monitor Sound Field Composer The semiconductor used Transistor: 45 pieces Diode: 24 Power outlets Power switch interlock: Dual power switch unsynchronized: 1 system Power AC100V, 50Hz/60Hz External dimensions 138 × depth 296mm height width 420 × Weight 10kg Dbx dbx No, Dolby A was developed in the 1960s for studios and Dolby B near the end of the decade as I understand it. A lot of people didn't see the need for it at first but it took off eventually and when introduced in cassette decks it made a difference with mostly lower grade ferrics as high end until Chrome tapes were introduced. Signal to noise figures then were in the realm of 40-55 dB so with good tape and B NR you could easily top 60 in a quality deck. This is actually good because it matched well with the phonograph stages of the day. When quieter sources and better circuits came about it became apparent that more was needed. This is likely how dbx got it's place in the market. dbx is short for David Brownfield(?) eXpander or similar. As I recall it was introduced around 1971? The concept is brilliant and seems frightfully simple, whether it was then or not. With voltage control amplifiers (VCA) the level can be logarithmically reduced by 50% and expanded to the original 1:1, technically pushing the perceived noise floor far below that acheived by Dolby (30 dB is a good figure, can be more). When a version is applied to records the results (dbx disc) can be closer to what we'd expect from a CD. Static, deposits and wear would be the lone drawbacks, no longer a real noise factor. With a good quality of vinyl and pressing the sound can be quite nice! I've heard that the Teac reel to reel decks with dbx actually use type II but don't quote me. I have a model 155 4-channel type I and two, soon to be three NX-40 units. Type II isn't so inferior that it won't suffice for reel recordings and type III and onward have been introduced in recent times in professional equipment. Other offerings from the company have included limiters, single-ended expanders, routing switchers like the 200 amd 400 series and a large range of professional equipment. The current company is a part of Harman International and is mainly a professional audio equipment provider. DVDA authoring sox Convert bitrate for dir: mkdir 96 # make subdir for converted files for i in *.flac; do sox "$i" "96/$i" rate 96k ; done lplex Audio files must be wav or flac, dvd-compliant: 16 or 24 bit 48 or 96 khz 1-8 channels and match within each titleset. 20 bit audio is not supported. create a .ISO with files from directory: lplex -t pal -c iso -C yes -L yes -l padded *.flac -t ntsc|pal|secam -c lpcm|m2v|dvdstyler|mpeg|dvd|iso --cleanup, -C yes|no delete interim files when done. --dir, -d output everything to this directory. --dvdpath, -p |adjacent output dvd files to this directory. --workpath, -w use this folder for temporary space. --isopath, -a |adjacent output disc images to this directory. --extractpath, -E |adjacent extract to this directory. --unauthor, -u extract audio from dvd. --formatout, -f wav|flac|flac#|raw extract audio to this format. (flac equals flac8) --verbose, -v no|yes --color, -L yes|no|dark|bright --splice, -l seamless|discrete|padded|none splice the tracks together this way. How to physically structure the immediate track transition point: seamless ("concert" mode - lossless, gapless, unpadded). Track startpoints will be shifted to where audio and video frames are in alignment, ensuring gapless playback and no need for any padding between tracks. Shift direction is determined by the shift setting (see below). discrete ("compilation" mode - lossless with gaps and padding). Tracks will be padded with silence to the next full audio frame in order to pre- vent stream truncation during multiplexing. A playback gap (equal to video duration - audio duration) is introduced. An additional half-second pause will also occur during playback because of stc discontinuity. padded ("compilation" mode - lossless with padding only). Tracks will be padded with silence to the next point of a/v frame alignment. Unlike discrete there is technically neither a playback gap nor a discontinuity pause in this model, though the padding is much greater. none ("as-is" mode - lossy, unpadded, with gaps). Tracks will be padded to next dvd sample unit if required. Audio will be dropped at the end of each track, unless your files happen to be the exact length to require no truncation. The purpose of this setting is to achieve clean, efficient transitions and to avoid undesirable playback artifacts such as gaps and pops. It is not intended as an audio effect and its scope is always less than one video frame. If you want an extended pause between tracks you must include physical silence in your source audio. Velleman PCSGU250 creating an wave sequence Creating an wave sequence Wave Sequence This option is used to run a sequence of waveforms under a timer control. Affected parameters are function (Sine, Square, Triangle or Library waveform), frequency, offset and amplitude for each step. The sequence may contain any number of steps. The command strings may be entered manually, loaded from a text file or received through the serial port. The data file is a normal text file. It can be edited using standard text editors or the editor of this option. At the startup there is an example file for editing in the edit window . When entering the data use Tab as a separator (do not use spaces). Use Save as option of the File menu to save the file. Click Open button to open a file. Click Run button to execute the sequence file. Select Repeat check box to repeat the sequence over and over again. Click Exit to break the execution. The file contains on each line following data: Function [1, 2, 3, 4 or 0] Frequency [Hz] Offset [V] Output voltage [Vpp] Time [s] File name (*) (Only if function number 4 is selected) Note: If the Time parameter is set to 0 then the generator outputs the waveform until you click the Next Step button or press Enter or the Space Bar. Function selection 1 = Sine 2 = Square 3 = Triangle 4 = Library waveform 0 = No change (The previous selected waveform is used.) Example of the file 1 12000 -1.5 7.5 30 2 24000 0 5.5 60 4 400 5 10 20 burst01.lib 0 500 4 9 15 Line 1: Generator outputs sine wave at 12000Hz, -1.5V offset and 7.5Vpp output voltage for 30 seconds. Line 2: Generator outputs square wave at 24000Hz, 0V offset and 5.5Vpp output voltage for 60 seconds. Line 3: Generator outputs library waveform "burst01.lib" at 400Hz, 5V offset and 10Vpp output voltage for 20 seconds. Line 4: Generator outputs library waveform "burst01.lib" at 500Hz, 4V offset and 9Vpp output voltage for 15 seconds. Receiving the command strings through the serial port In this mode you can remote control the operation of the function generator. Select Serial Port radio button in the Source Data box. Set the communications parameters such as COM port, baud rate, data bits, stop bits and parity. The software is ready to receive the command strings from the serial port. If the Time parameter is set to 0 then the generator outputs the selected waveform until the next instruction is received from the serial port. Note: Make sure that the library waveform files are located in the Lib subfolder of the PcLab2000LT program folder (normally C:\ProgramFiles\Velleman\PcLab2000LT\lib). Degaussing It takes alot more power to erase DV tapes than what Hand Held Radio Shack Bulk Tape Erasers can handle. Here's a chart showing the power needed to erase DV Tapes. (It takes 1700 Oersteds to erase DV tapes.) Coercivity is the property of a given magnetic pigment to resist changes in magnetic orientation or re-orientation (= "erasure"). It is defined by the level of the magnetic field needed for (re-)orientation, expressed in Oersted (Oe). The higher the coercivity, the higher the resistance of magnetic information to re-orientation (or erasure) by external magnetic fields. AUDIO Tapes Oersteds ================================== 350 Oersteds = 1/2", 1" and 2" 350 Oersteds = Cartridge 350 Oersteds = Sep.mag.35mm film 365 Oersteds = Voice logging reel 1/2", 1" 450 Oersteds = Compact cassette ferric (IEC Type I) 450 Oersteds = Compact cassette chrome (IEC Type II) 680 Oersteds = 1/4", 1/2" digital audio reel 745 Oersteds = 3/4" digital audio cassette 10/750 Oersteds = Pancake various 700 Oersteds = DCC 930 Oersteds = ADAT 1440 Oersteds = RDAT COMPUTER/Data Tapes Oersteds ================================== 300/700/1500 Oersteds = Floppy diskette 51/4",31/2" 550 Oersteds = PC,Mini, Hard disk 310 Oersteds = Main-frame Spool 1/2" 550/650 Oersteds = Cartridge 1500 Oersteds = TK50 etc. 700 Oersteds = DCRSI cassette 310 Oersteds = Reel 1/2", 1" 675/750 Oersteds = Cassette 1050/1500 Oersteds = 8mm/4mm 1440 Oersteds = DAT-R 550 Oersteds = Cartridge 3480, DC600A 1900 Oersteds = Digital backup cartridge VIDEO Tapes Oersteds ================================== 750 Oersteds = Reel 1"`B'and`C' format 300 Oersteds = 2" 675/750 Oersteds = VHS pancake 2100 Oersteds = Mirror master 675/700 Oersteds = Cassette VHS 710 Oersteds = Beta 1000 Oersteds = SVHS 1050/1500 Oersteds = Hi8 630 Oersteds = U-matic 745 Oersteds = U-matic SP 1700 Oersteds = Beta SP, MII 850 Oersteds = D-1 1700 Oersteds = D-2, D-3 Digital 1700 Oersteds = Digital Betacam, D5 Digital 1700 Oersteds = DV, DVC, DVCAM, DVC PRO SECURITY formats Oersteds ================================== 600 Oersteds = Credit card 600 Oersteds = Library ticket 600/3500 Oersteds = Rail/Air ticket 600 Oersteds = Hotel door lock (INFO FROM: Weircliffe) Here's something interesting: ============================== From: Art Munson Subject: Degaussing, erasing and magnetism Date: Tue, 27 Aug 1996 11:58:42 -0500 (CDT) Degaussing, Erasing and Magnetism --------------------------------- A lot of folks have asked about degaussing (erasing) media and particularly DAT tapes, so here's some info you might find helpful. Gauss: A unit of measurement of magnetic flux density produced by a magnetic force (coils). Gauss is a measurement of coil strength. Oersted: A unit of magnetic intensity of a magnetic field in a vacuum. Oersted is a measurement applied to media. A 4mm DAT tape has a magnetic field strength of approximately 1500 oersteds. Coercivity: The amount of applied magnetic field (of opposite polarity) required to reduce magnetic induction to zero. The ease or difficulty by which magnetic media can be de-magnetized. A 4mm DAT tape is a high coercivity tape. So: 1.) The higher the oersted rating, the more energy needed to *properly* demagnetize it. 2.) In order to degauss (erase) a magnetic tape, a magnetic force (gauss) of 2 2/3 to 5 times greater than that of the media to be degaussed must be created. In other words to demagnetize a media of a given oersted rating, it will take 2 2/3 to 5 times the amount of energy. 3.) A 1500 oersted tape would need a magnetic field strength in the neighborhood of at least 3000 gauss in order to *properly* erase it. Hope this helps and thanks to David Partridge for his input. There is a hand held DAT degausser available, with an oersted rating of 2800, that lists for $169. Please give a call at 800-321-5738 if you are interested. Art * Cassette House * e-mail:artmuns@tape.com * DAT tape - CDR's - Cassettes * web page http://www.tape.com/ch * 800-321-5738 "I will use no track before its time" (INFO FROM: DAT Digest) ================================== Radio Shack's High Power Gauss Field is 800 oersteds. Specs ================================== So as you can see, degaussing DV tapes can be done with the right equipment. Let's see...to erase a DV tape of 1700 Oersteds I need a degausser that can handle 3400 Oersteds. Hmmm, The Radio Shack High Power Bulk Tape Eraser handles 800 Oersteds. No wonder it didn't work. SOX audio examples THX-like sound play -q -n synth sq F2 sq C3 remix - fade 0 5 .1 norm -4 bend 0.5,2477,3 fade 0 5 0.8 white noise play -n -c1 synth whitenoise lowpass -1 120 lowpass -1 120 lowpass -1 120 gain +14 play keys piano asdfghj n=CDEFGAB;l=asdfghj;while read -n1 k;do x=$(tr $l $n<<<$k);play -qn synth pl ${x}3 fade 0 .7 & done warble sound play -n synth sq C trim 0 4 vol 0.2 chorus 1 1 21 1 4 10 -s bend 0,2400,4 fade 0.1 4 2 convert bitrate sox "02 It's Time.flac" -b 16 -r 44.1k "02 It's Time 44100.flac" converts from 48000 to 44100 Doormeten van een transistor het testen van een transistor is vrij eenvoudig: je zet je multimeter op het diode teken, daarna pak je de plus pool, rode draad van je multimeter en je zet deze op de basis van de transistor, tussen basis en emitter en tussen basis en collector meet je nu de spanning van de PN overgang,(+-0.6v) draai de klemmen om en je mag geen spanning meten, tussen collector en emmitter mag je nooit spanning meten met + aan de basis heb je met een NPN te doen, met de min aan de basis heb je met een PNP te doen.... of nog makkelijker, neem er een waarvan je weet welke type het is en doe de bovenstaande test... als je weet dat je transistor goed is kan je de versterking meten door hem correct aan te sluiten aan de drie puntjes van je multimeter, je krijg normaal maar op 1 manier een correcte waarde.. Dolby NR Q. What is different about the varieties of Dolby noise reduction? By Hugh Robjohns I never did quite understand the subtle differences between all the different variants of Dolby — A, B, C, HX and SR. Could you explain them to me? Are there any others I've missed? What are Dolby Labs doing these days? I guess they've undergone some 'reduction' themselves... Technical Editor Hugh Robjohns replies: Dolby A was the first professional noise-reduction system — launched in 1967 if memory serves — and it used four separate frequency processing bands. You can think of them crudely as bass, mid-range, treble and high treble, with the top two overlapping so that the 'hiss region' was processed more heavily than the rest. Avoiding line-up errors between encoding and decoding was crucial, so the infamous Dolby warble tone was used to identify encoded tapes and to allow accurate replay alignment. Dolby A was originally used to get respectable audio performance out of early professional video recorders, but was later adopted for multitrack recording and cinema optical soundtracks. Dolby B was a very simple domestic system intended to improve the performance of compact cassette recorders. It was also used on some later domestic quarter-inch machines. Dolby B was a single-band system affecting only the high end, with very modest compansion. It had no facility, or indeed any practical need, for replay alignment. Dolby C was a much more aggressive multi-band version originally intended for small-format professional video-tape systems and narrow-gauge semi-professional studio multitrack recorders. It was very sensitive to mistracking, but was unfortunately designed without any line-up tone facility to calibrate playback levels. In the professional market, Dolby A was superseded by Dolby SR , which was Dolby's most sophisticated multi-band noise reduction system. This employed 10 bands altogether, some operating at fixed frequencies and others moving automatically to suit the material, and allowed the user to achieve a signal-to-noise ratio of around 90dB from analogue tape. However, although it was a very clever and effective system it arrived just a few years too late and the digital revolution effectively eclipsed it. Dolby SR used a modulated noise signal for identification and replay alignment. Finally, Dolby S (one you missed off your list) was a last-ditch attempt aimed at semi-pro and domestic recorders, and was a halfway house between Dolby SR and Dolby C. It still had no built-in line-up facility, though. It was used on some semi-pro narrow-gauge multitrackers and the last of the high-end hi-fi cassette recorders. Dolby HX is not a noise-reduction system at all — it is a clever system to avoid over-biasing on analogue tape machines using high-output tapes. This system was used on some high-end domestic cassette recorders and the last of the professional analogue two-track machines, such as the Studer A807. Dolby HX is a once-only process that needs no decoding. In essence, it reduces the bias level if there is a lot of high-frequency content in the audio signal, thus preventing over-biasing and the noise artefacts and frequency-response errors that go with it. Dolby Labs still make Dolby SR and A systems for analogue multitrack and cinema applications, and I guess they are still collecting licensing revenues from the other systems when they are used on domestic cassette recorders and the like. However, most of the company's efforts these days are geared towards digital data-reduction systems, which are based entirely on the frequency-masking principles first exploited by Dolby's analogue noise-reduction systems. That is why Dolby AC3 has always been amongst the best of the data-reduction codecs for a given data rate — the company had a major head start on the rest of the field. BASF tape formulas Type IV - metal pigment (MP) [or metal evaporated (ME) tape whose extremely thin coating rendered it poor for analogue audio recording]. TDK made the official IEC reference tape. The pigment is such a small crystal that it can oxidize extremely quickly, enough to cause spontaneous combustion or explosions at any point in the milling/coating operation unless extreme precautions are taken, such as submersion in alcohol and a nitrogen-based environment. The particles were passivated with molecules of oxygen around the metal crystal to stabilize them because early metal tapes oxidized and lost magnetic properties. There were other experiments to modify the crystals with other metallic alloys either to enhance magnetic properties or to stabilize the crystals. Metal tapes are relatively environmentally stable with the lowest amount of print-through. They generally have the highest MOL and SOL values, but also the highest noise, so in practice they exceed Type II tapes only in low print and better high frequency dynamic range. Headwear is no different from that of any other magnetic pigment. Type III -ferric-chrome tapes. Sony made the IEC reference tape. Thicker coatings increased MOL, and the "underbiased" thin layer of chromium dioxide brought low noise. However, the disparity in bias points between the two layers meant a sagging mid-frequency sensitivity that had to be compensated by boosting record EQ to such a degree that SOL values were very poor. (This was common to double-coated tapes but far less pronounced when the optimum bias points were closer, as in BASF Superchrome tapes and TDK SA-X.) Type III tapes were never very popular and disappeared with the arrive of Type IV formulations. Headwear was the same as that for pure chrome tapes: lowest of all tapes for soft heads; higher initial wear on hard heads until the granular ferrite surface was polished, then very low with little to no gap erosion over the life of the head (except for some Sendust heads were chemical, not mechanical, erosion was observed similar to that induced by some ferric-cobalt formulations.) Type II - chromium dioxide or ferric-cobalt pigment. BASF made all Type II reference tapes, despite what TDK claimed in its misleading advertising. These tapes used either DuPont's invention of chromium dioxide (manufactured only by DuPont of BASF because of the enormous expense in heat/pressure reactors required to form the particle) or ferric oxides enhanced by the addition of magnetic cobalt to the crystal structure. Chrome was the first Type II tape, but Sony's exclusive distribution deal with DuPont forced other Japanese tape manufacturers to find an alternative in ferric-cobalt (an Agfa-Gevaert invention that they were never able to stabilize properly until the Japanese figured how to do it.) Chrome had the lowest noise because of its perfect particle size and near perfect uniformity that allowed easy distribution in dispersions and excellent alignment under orientation magnets in coaters, but the first chromes also broke in milling and were susceptible to high print-through. Ferric-cobalts allowed higher packing densities that increased tape sensitivity at the lower frequencies--a compatibility point that the Japanese used as a "quality" issue against chrome tapes--and allowed higher MOL values. The tapes, however, suffered from higher noise levels, which actually increased over time as delta noise, and from magnetostrictive effects that reduced high frequency signals under pressure from the capstan/pinch roller combination. Chrome suffered from neither and actually had its noise level decrease over time--along with output--so the dynamic range stayed the same while Dolby noise reduction tracking was compromised a bit--with a slight loss in accuracy but a pleasant increase in treble response. BASF redesigned its milling operations to reduce print-through to levels equal to or better than ferric-cobalt tapes and improved MOL and SOL values with new particles and finally, the introduction of ferric-cobalt oxides with chrome for the "Chrome Extra" formulations. The same improvements were made to the double-coated Superchromes and Chrome Maxima tapes. TDK, frustrated by chrome's claims to be the "world's quietest tape," introduced double-coated SA-X with a very fine ferric-cobalt particle coated on top of the standard SA formulation. This lowered noise levels about a decibel or so below that of pure chrome tapes (before delta noise set it) but brought the curse of increased print-through due to the presence of para-magnetic particles among the finely milled top layer particles. All producers of ferric-cobalt tapes made improvements to formulations that slowly increased output levels with few compromises to dynamic range. BASF itself introduced a ferric-cobalt tape in a heat-resistant housing for car stereo use because chrome's low Curie point meant that signals could be lost if the tape were subjected to high levels of heat. (This worked to chrome's advantage when used in highs-speed TMD thermal magnetic video duplication.) Barium ferrite was an alternative pigment considered for audio but seldom used except for some video applications. Despite the nasty headwear scare used to dissuade people from using chrome tape, there is little difference in the amount of wear induced by any Type II tape that is properly calendered and finished. (All lubricant, emulsifiers, static reducers, and fungicides are in the magnetic dispersion. They are not added later in the manufacturing process.) There were some Type II metal tapes in the market to offer metal recording for older tape decks without Type IV settings, but the lower MOL and SOL values along with the very high noise levels and inability to be erased eventually killed these interlopers. The best ferric-cobalts and chromes easily outperformed these metal pigment products. Chrome tapes had their greatest day in audio duplication because BASF encouraged duplicators to use a playback EQ of 120 microseconds and back off the record pre-emphasis to improve SOL values by almost 5 decibels. (The 70-microsecond EQ setting came about when no one expected Dolby NR to become standard. Had the engineers known Dolby would be so successful, they would have left playback EQ the same for Type II tapes as for Type I. Chrome/Dolby NR/70 microseconds were all introduced at the same time to reduce tape hiss--but any two of the three options would have been sufficient. All 3 at the same time was overkill.) Type I - ferric oxide, cobalt-modified ferric oxide. BASF made the official reference tape. These are the first and most common tapes. The range of quality levels is greatest in this class because the oxides can vary so much and because reject computer tape designed for digital signals, not audio, sometimes made its way into cheaper brands. Some of the best Type I tapes could offer low frequency signal-to-noise ratios that matched or slightly exceeded Type II and IV tapes, but their high frequency performance was never as good because of the lower coercivity of the oxides. These tapes, with their less sophisticated particles, tend to be the most environmentally stable over time as long as the binder formulations are stable. (Polyurethane binder breakdown is a plague among ferric reel-to-reel formulations from Ampex and Agfa; acid ooze is more common in cassette binder failures.) Headwear varies among tapes only because of different levels of quality in finishing the tapes: the better quality of tapes have no problem. Some ferric-cobalt Type I tapes have shown some chemical erosion on some Sendust heads, but one could argue whether it is the fault of the tape or the head design. In general, headwear is not a problem. (As a topic, headwear is a fascinating topic, rife with misinformation and rumors.) --------------------- DIN Type II Reference Tape C 401 R BASF 100% pure chrome IEC Type II Reference Tape S 4592A BASF 100% pure chrome IEC Type II Reference Tape U 564 W (replaced S 4592 A in October, 1987, in the IEC meeting in Prague) Magnetic Media Information Services, Volume XIII, No. 5 (August 20, 1993) discusses the technical work of Dr. Manfred Ohlinger, BASF's chief of pigment development. Dr. Ohlinger discussed work on CK60/XH, a chrome pigment with a coercivity beyond 1000 oersteds. He had already produce CK/75/230X with a value of 900 oe. and CK57/200X with a value of 670 oe. BASF was in full development of advanced pure chrome pigments for new 3480 cartridges and other media. BASF had been producing pure chromium dioxide pigments in a huge reactor in Ludwigshaven, Germany, since the late 1960s. In 1995 the oxide lineup included: CK 40-14 for audio tape CN 43-11 for high performance, single-coat audio tapes CK 37-11 for the lower coating of high performance chrome audio tapes. This pigment was designed for non-cross-linked binders. CK 48-21 was for the upper layer in cross-linked dispersions. These oxides were used in Chrome Super and Chrome Maxima tapes. The tapes were identical and differed only in the housing and the tighter specs for Chrome Maxima. Most Chrome Super performed exactly the same as Chrome Maxima. CK 50-21 was pure chrome used in VHS, S-VHS, TMD, and DCC formulations. (BASF made the only DCC tape. It was the tape in TDK and every other DCC cassette made.) There were CC variations of these pigments. They differed in that oxygen molecules were attached to the crystal surface to prevent degradation to hexavalent chrome in the presence of water. BASF used 100% pure chrome formulations for its EE reel-to-reel tape and for Loop Bin Master 920 and 921 used in the duplication industry before digital bins arrived. The only "hybrid" chrome/cobalt audio formulations appeared with the introduction in 1993/94 of "Chrome Plus" duplicator tape that had a small percentage of cobalt-ferric pigment added to raise AT315/MOL315. Its AT315 was 2-3 dB better than competing chrome tapes. Chrome Plus was also used in Chrome Extra audio cassettes from that point forward. In 1992 world-wide production of magnetic powder by weight was 11% for chromium dioxide, 55% for co-fe, 32% for standard ferric, and 2% for metal powder. This total includes all applications: audio, video, computer data. In 1994 BASF used a high-performance plastic that could withstand 95 degrees C. (203 degrees F.) without deformation. This plastic was used in the sonically welded Reference Maxima series. The tape was BASF ferric-cobalt because the heat resistance of the plastic would be wasted on a tape that had a much lower Curie point. (It was chrome's low Curie point that made it the only choice for thermal duplication--TMD--that was used for high-speed video tape duplication.) BASF kept Chrome Maxima and Chrome Super in the cassette lineup as 100% pure chromium dioxide tapes and the 85/15 Chrome Extra as its first and only hybrid chrome audio tape. As for "audiophile" opinions, I remember reading a discussion in The Absolute Sound condemning the process. It was obvious that the writer, an editor at the magazine, had little idea of magnetic recording. If you want an audiophile journalist's perspective on high-speed duplication, you would have to turn to John Borwick or Angus MacKenzie's work in British publications. DCC tape Quote: The tape formulations supplied by manufactures was actually from video tape stock rather than cassette stock, i.e. mostly chromium tapes but cobalt doped ferric formulations were also available at the least in the early days of DCC, for archival purposes the ferric formulations have a longer lifetimes despite the lower price, this use of video tape stock explains why metal tape playback is not officially supported in the DCC standard. A few chromium audio cassette formulations are very similar to video tape formulations so that it's theoretically possible to force some audio cassettes to work in a DCC recorder by modifying the enclosure and tape pad (if you need to seriously over-bias a chrome tape to make it sound right on an analogue recorder, chances are that it's video stock), but no audio cassette ferric formulations are similar to the video type ferric formulations that DCC expects. It's hard to make sense out of what the author is writing, partly because of poor grammar and punctuation, partly because of misinformation. DCC was NOT video tape "stock." It was audio base film coated with CK 50-21 pure chrome pigment, which was also used for VHS, S-VHS, and TMD video formulations in different dispersions and different processing. TDK, Panasonic, and other Japanese tape manufacturers didn't bother with producing ferric-cobalt DCC tape. They bought pancakes from BASF because they wanted a hand in the DCC jar just in case consumer demand picked up, but they didn't want to invest too much in risky development. (BASF initially did the same with DAT. We sourced the first BASF DAT tape. Tape manufacturers were being cautious at the time because there were too many formats to develop all of them and too many losses from the VHS consumer market.) The sentence fragment starting with "for archival purposes...." makes no sense to me. The same is true regarding metal tape playback. The author is probably British judging from the language used, so I don't know where he or she got the information. Lagers identificatie Kogellagers zijn in verregaande mate gestandaardiseerd. Nummercodes identificeren een specifiek type kogellager. Meestal is op het kogellager de nummercode gestanst. C-aanduidingen zeggen iets over de speling van de binnenring t.o.v. de buitenring binnen het lager. C3 is de meest voorkomende variant. Dit is een lager dat gelijk is aan zijn C0 genummerde broertje met uitzondering van de speling, die is dus groter. Men heeft ook nog C1 die heeft een veel kleinere speling dan C0 (de standaardmaat) en C2 met een kleiner speling dan C0, maar iets groter dan C1. Verder is er naast de genoemde C3 ook nog een C4 en C5, die hebben een nog grotere speling. In volgorde van speling beginnende bij de strakste zijn de codes: C1, C2, C0, C3, C4 en C5. Bij inline-skates is de Amerikaanse onderverdeling ABEC standaard. De schaal loopt van ABEC 1 tot ABEC 9 (de nauwkeurigste lagers). coderingen Overzicht codering toevoegingen inzake afdichting & speling SKF FAG NTN SNR NKE Koyo NSK Nachi 1-zijdige metaal-afdichting Z Z Z Z Z Z Z Z 1-zijdige rubber-afdichting RS1/RSH RSR LU E RSR/RS2 RS DU Z 2-zijdige metaal-afdichting 2Z 2Z ZZ ZZ 2Z ZZ ZZ ZZ/ZZE 2-zijdige rubber-afdichting 2RS1/2RSH 2RSR/C-2HRS LLU EE 2RSR/2RS2 2RS DDU 2SNL/2NSE speling groter dan normaal C3 C3 C3 J30 C3 C3 C3 C3 speling groter dan C3 C4 C4 C4 C4 C4 C4 C4 C4 speling kleiner dan normaal C2 C2 C2 C2 C2 C2 C2 C2 Tot slot nog een paar opmerkingen. Lagers waarbij geen toevoeging is vermeld, hebben geen afdichting daar bij de toepassing rekening gehouden word met de (constante) smering van het lager; Lagers die een 2Z afdichting hebben zijn stofdicht en hebben een hoger maximaal toerental dan de rubber afgedichte varianten; Lagers die een 2RS1 afdichting hebben zijn spatwaterdicht. Dit betekent overigens geenszins dat deze lagers waterdicht zijn!; RVS lagers worden aangeduid met een S en W voor de codering van het lager. Bijvoorbeeld SKF W6004 2RSH of ECO S6004 2RS tabel In onderstaande tabel staan de meest gangbare coderingen voor kogellagers, m.u.v. spanring kogellagers,spindellagers en vierpunts-kogellagers. Doordat de lagerfabrikanten niet allemaal dezelfde lageraanduidingen gebruiken, kan het zijn dat er voor een bepaalde eigenschap verschillende afkortingen bestaan. SKF FAG NTN 2RS12RSH 2RSRC-2HRS LLU : spatwaterdichte slepende afdichting van rubber met wapening van staalplaat aan beide zijdes van het lager 2RSL : wrijvingsarme variant van 2RS1 2RZ : wrijvingsarme variant van 2RS1 2Z 2Z ZZ : geperst stalen beschermplaatje (stofafdichting) aan beide zijdes van het lager A : hoek is 30 graden (1-rijig hoekcontactkogellager) A : geen vulopeningen + hoek is 30 graden   (SKF 2-rijige hoekcontactkogellager) B B B : hoek is 40 graden (1-rijig hoekcontact kogellager) B : hoek is 25 graden (FAG 2-rijige hoekcontactkogellager) C2 C2 C2 : radiale speling kleiner dan normaal C2 : axiale speling kleiner dan CB (2-rijige hoekcontactkogellager) C3 C3 C3 : radiale speling groter dan normaal C3 : axiale speling groter dan CB (2-rijige hoekcontactkogellager) C4 : radiale speling groter dan C3 C5 : radiale speling groter dan C4 CA : lager voor gepaarde montage, bij O- of X-opstelling is de axiale speling in ongemonteerde toestand kleiner dan CB CB UA : lager voor gepaarde montage, bij O- of X-opstelling is de axiale speling in ongemonteerde toestand normaal CB : speciale axiale speling  (2-rijige hoekcontactkogellager) CC : lager voor gepaarde montage, bij O- of X-opstelling is de axiale speling in ongemonteerde toestand groter dan CB D DA : gedeelde binnenring (2-rijige hoekcontactkogellager) DB DB : 2 gepaarde kogellagers in O-opstelling DF DF : 2 gepaarde kogellagers in X-opstelling DT DT : 2 gepaarde kogellagers in tandem-opstelling E : geoptimaliseerde inwendige constructie hoekcontactkogellagers F : massief stalen vensterkooi hoekcontact kogellager GA UL : lager gepaarde montage; bij O- en X-opstelling is er in ongemonteerde toestand een lichte voorspanning GB : lager gepaarde montage; bij O- en X-opstelling is er in ongemonteerde toestand een matige voorspanning GC : lager gepaarde montage; bij O- en X-opstelling is er in ongemonteerde toestand een zware voorspanning UO BG : lager gepaarde montage; bij O- en X-opstelling is in ongemonteerde toestand spelingsvrij J JP J : geperste kooi van staal, op de kogels gecenteerd J1 : idem J  (2-rijige hoekcontactkogellager) K K  : Conische boring M M / MP L1 : messing kooi op kogels gecenteerd MA MA : messing kooi op buitenring gecenteerd MB : messing kooi op binnenring gecenteerd N : borgringgroef in de buitenring N1 : 1 borggroef op zijvlak buitenring NR : borgringgroef in de buitenring + borgring P : kooi van glasvezelversterkte polyamide bij hoekcontact kogellagers P5 : maat- en loopnauwkeurigheid ISO 5 P52 : P5 + C2 P6 : maat- en loopnauwkeurigheid ISO 6 P62 : P6 + C2 P63 : P6 + C3 PH : kooi van glasvezelversterkte polyether-etherketone (PEEK) bij hoekcontact kogellagers RS1/RSH RSR LU : spatwaterdichte slepende afdichting van rubber met wapening van staalplaat aan een zijde van het lager RSL : wrijvingsarme variant van RS1 RZ : wrijvingsarme variant van RS1 TH : kooi van vezelversterkte fenolhars op kogels gecentreerd TN : kooi van polyamide op kogels gecentreerd TN9 TVP/TVH : kooi van glasvezelversterkte polyamide op kogels gecentreerd TNH : kooi van glasvezelversterkte polyether-etherketone (PEEK) op kogels gecentreerd Y Y : geperste kooi van messing, op de kogels gecenteerd Z Z : geperst stalen beschermplaatje (stofafdichting) aan een zijde van het lager Voorbeelden: SKF 6005 2RSH = groefkogellagers met spatwaterdichte slepende afdichting van rubber met wapening van staalplaat aan beide zijdes van het lager; FAG 3202B 2RSR TVH = 2-rijige hoekcontactkogellager met een hoek van 25 graden, kooi van glasvezelversterkte polyamide op kogels gecentreerd en spatwaterdichte afdichting; uitleg Deze codering is officieel als volgt: voorvoegsel  -  hoofdnummer  -  volgcode_A  volgcode_B   volgcode_C  /   volgcode_D1 t/m D6 Je ziet dat deze codering vrij ingewikkeld is. Immers: niet altijd wordt het voorvoegsel of worden de volgcodes allemaal gegeven.Het is dus ook goed mogelijk dat alleen het hoofdnummer en volgcode B wordt gegeven. Stel je voor dat je een lager  DIN625 6201Z  hebt. Wat voor lager heb je dan? Dat is de vraag die we hier gaan beantwoorden.Aan het eind van deze faq kan jij dit decoderen. Dus lees snel verder. Voorvoegsel Het voorvoegsel wordt zelden genoemd. Daarom zal ik die hier niet bespreken. Hoofdnummer Veel voorkomende lagers zijn hieronder te vinden, met hun maten. Alle lagers zijn in Z, ZZ, RS en RS2 verkrijgbaar. De maten zijn in  millimeters   weergeven. Code d Diameter binnen D Diameter buiten B Hoogte 6000 10 26 8 6200 10 30 9 6300 10 35 11 6001 12 28 8 6201 12 32 10 6301 12 37 12 6002 15 32 9 6202 15 35 11 6302 15 42 13 6003 17 35 10 6203 17 40 12 6303 17 47 14 De hoofdcode uit het voorbeeld is  6201 . We gaan dit als eerste decoderen.De hoofdcode bestaat uit cijfers en is gerelateerd aan het soort lagers en de grootte ervan.Het eerste cijfer geeft het soort lagers weer. In het voorbeeld is dat dus een  6 . code verklaring 0 Dubbelrijig hoekcontact lagers 1 Zelfinstellend kogellagers 2 Tonlagers 3 Kegellagers 4 Tweerijig groef kogellagers 5 Axiale kogellagers 6 Groef kogellagers 7 Hoekcontact lagers 8 Axiale cilinder lagers N cilinderlagers Het lager in het voorbeeld is dus een  Groef kogellager . Dit het meest 'gewone' kogellager wat wij kennen. Dus een gewoon lager. De rest van de cijfers van de hoofdcode geven de maatvoering aan. Volgcode's A t/m D De volgcode's A t/m C worden door een spatie gescheiden.Meestal is er maar een van de 3 code's aanwezig. Indien er een volgcode C is aangegeven, is er nooit een volgcode D opgegeven. Volgcode A De volgcode A geeft informatie over het  inwendige  van het lager.Dit zal niet vaak voorkomen. code verklaring A Speciaal ontwerp voor speciale toepassing A Contacthoek 30 Graden bij hoekcontact lagers B Contacthoek 40 graden bij hoekcontact lagers B Contacthoek kleiner dan 17 graden bij kegel lagers C Contacthoek 15 graden bij hoekcontact lagers C Contacthoek 20 graden bij kegel lagers CA Contacthoek 20 graden bij hoekcontact lagers D Contacthoek 28 graden en 30 minuten voor kegel lagers DJ Contacthoek 28 graden en 48 minuten en 39 seconden voor kegel lagers E Contacthoek 35 graden bij hoekcontact lagers J Bepaalde maten van een kegellager voldoen aan de ISO standaard Volgcode B Deze volgcode B geeft aan hoe de  afdichting  is bij het lager. code verklaring (geen code) het lager is aan beide kanten open RS  / RS1  / RSH het lager is aan een zijde spatwater dicht dmv 1 rubberen afdichtring 2RS / 2RS1 / 2RSH het lager is aan twee zijden spatwaterdicht dmv 2 rubberen afdichtringen RSL het lager is aan een zijde spatwaterdicht met extra lage wrijving 2RSL het lager is aan twee zijden spatwaterdicht met extra lage wrijving Z het lager is aan een zijde stofdicht dmv 1 metalen plaatje 2Z = ZZ het lager is aan twee zijden stofdicht dmv 2 metalen plaatjes Het lager in het voorbeeld heeft bij volgcode B een  Z . Dit geeft dus aan dat dit lager aan 1 kant is dichtgemaakt met een metalen plaatje. Volgcode C Deze volgcode C geeft informatie over de  kooiconstructie . Dus over de 2 stalen ringen waarin de kogel draaien. code verklaring (geen code) standaard: massief ijzeren kooi F Massieve ijzeren kooi J Geperste plaatstalen kooi L Massieve lichtmetalen kooi M Massieve messing kooi P Met glasvezel versterkte polyamide kooi Y Geperste kooi ven messing plaat Volgcode D Achter het  /  teken staan de kenmerken t.a.v. materiaal,hittebehandeling, nauwkeurigheid,extra speling, smering e.d.. code categorie verklaring P0 Nauwkeurigheid klasse 0 van de ISO tolerantie-klassen = ABEC 1 P2 Nauwkeurigheid klasse 0 van de ISO tolerantie-klassen = ABEC 9 P4 Nauwkeurigheid klasse 0 van de ISO tolerantie-klassen = ABEC 7 P5 Nauwkeurigheid klasse 0 van de ISO tolerantie-klassen = ABEC 5 P6 Nauwkeurigheid klasse 0 van de ISO tolerantie-klassen = ABEC 3 C1 Extra speling Krappere speling dan bij C2 C2 Extra speling Krappere speling dan bij C3 C3 Extra speling Speling normaal C4 Extra speling Ruimere speling dan bij C3 C5 Extra speling Ruimere speling dan bij C4 Het voorbeeld uitgelegd Het voorbeeld wat is gaf was een DIN625 6201Z. We gaan nu kijken wat dat betekent: DIN625 Duitse Industrie Norm 625 Dit betekent dat het een kogellager is 6201 Hoofdnummer Dit geeft de afmetingen aan: 12mm binnendiameter; 32mm buitendiameter en 10mm dikte Z Volgcode B Dit geeft aan dat het lager aan 1 kant stofdicht is met een metalen plaatje Quadroponic or DTS surround sound REDIRECT Quadrophonic or DTS surround sound Play audacity over network How to play Audacity over network using pulseaudio sound server If you use pulse-audio as sound server, you can use module-native-protocol-tcp to accept tcp connection from your remote machine. In the following example, I use an ssh tunnel to forward the audio request from remote machine to the local one. On the local machine, do something like: $ pactl load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1 $ ssh -XC -R 9999:127.0.0.1:4713 pvdm@192.168.1.1 then on remote machine you can use: $ paplay -s 127.0.0.1:9999 soundfile.wav $ padsp -s 127.0.0.1:9999 audacity ADDED I discovered that auth-ip-acl does not accept localhost as a valid parameter, you have to use 127.0.0.1 (or whatever your machine uses localhost address). Check soundcard settings: bitrate To check settings Which sound cards are installed, and what number are they? > cat /proc/asound/cards 0 [NVidia ]: HDA-Intel - HDA NVidia HDA NVidia at 0xfc080000 irq 69 1 [Generic ]: HDA-Intel - HD-Audio Generic HD-Audio Generic at 0xfc500000 irq 72 2 [USB ]: USB-Audio - Scarlett 2i2 USB Focusrite Scarlett 2i2 USB at usb-0000:30:00.4-2.3, high speed 3 [Pro ]: USB-Audio - FiiO K5 Pro GuangZhou FiiO Electronics Co.,Ltd FiiO K5 Pro at usb-0000:30:00.4-1, high spee Focusrite Scarlett 2i2 > cat /proc/asound/card2/stream0 Focusrite Scarlett 2i2 USB at usb-0000:30:00.4-2.3, high speed : USB Audio Playback: Status: Stop Interface 1 Altset 1 Format: S32_LE Channels: 2 Endpoint: 0x01 (1 OUT) (SYNC) Rates: 44100, 48000, 88200, 96000, 176400, 192000 Data packet interval: 125 us Bits: 24 Channel map: FL FR Capture: Status: Running Interface = 2 Altset = 1 Packet Size = 200 Momentary freq = 192000 Hz (0x18.0000) Interface 2 Altset 1 Format: S32_LE Channels: 2 Endpoint: 0x82 (2 IN) (ASYNC) Rates: 44100, 48000, 88200, 96000, 176400, 192000 Data packet interval: 125 us Bits: 24 Channel map: FL FR UCA202: # cat /proc/asound/CODEC/pcm0p/sub0/hw_params # cat /proc/asound/card0/codec#0  access: MMAP_INTERLEAVED format: S16_LE subformat: STD channels: 2 <-------- will be 4 for iO4 rate: 48000 (48000/1) <------ this changes with the input audio file period_size: 44100 buffer_size: 88200 FiiO 48kHz and below: BLUE 48kHz and above: YELLOW DSD: GREEN # cat /proc/asound/card0/stream0 | grep Momentary or # cat /proc/asound/card1/stream0 | grep Momentary Momentary freq = 44095 Hz (0x5.8308) - - - - # cat /proc/asound/card0/stream0  # cat /proc/asound/card0/pcm0p/sub0/hw_params GuangZhou FiiO Electronics Co.,Ltd FiiO K5 Pro at usb-0000:00:12.2-3, high spee : USB Audio Playback: Status: Running Interface = 1 Altset = 2 Packet Size = 36 Momentary freq = 44095 Hz (0x5.8308) Feedback Format = 16.16 Interface 1 Altset 1 Format: S32_LE Channels: 2 Endpoint: 1 OUT (ASYNC) Rates: 44100, 48000, 88200, 96000, 176400, 192000, 352800, 384000, 705600, 768000 Data packet interval: 125 us Interface 1 Altset 2 Format: S16_LE Channels: 2 Endpoint: 1 OUT (ASYNC) Rates: 44100, 48000, 88200, 96000, 176400, 192000, 352800, 384000, 705600, 768000 Data packet interval: 125 us Interface 1 Altset 3 Format: SPECIAL Channels: 2 Endpoint: 1 OUT (ASYNC) Rates: 44100, 48000, 88200, 96000, 176400, 192000, 352800, 384000, 705600, 768000 Data packet interval: 125 us FiiO via S/PDIF # cat /proc/asound/card1/pcm1p/sub0/hw_params access: MMAP_INTERLEAVED format: S32_LE subformat: STD channels: 2 rate: 48000 (48000/1) period_size: 1024 buffer_size: 32768 Cm6631a The latest product upgrades, increase optical output! ! ! This product USB direct power supply, Input: USB input, print port and Android interface, input easily linked computer or mobile phone Output: output optical! Coaxial! Linear audio! Headphone output! Easily drive 300 European and American headphones A finished board, finished machine optional! Black or silver white shell! CNC high-precision machining, pure aluminum chassis structure, 6631 combined with multiple version optimization and improvement, sound sophistication beyond XMOS, Naiting, not irritable! Small exquisite children! ! Each board test OK delivery, using anti-static packaging .Windows10 automatic identification, you need to drive can contact me Support coaxial SPDIF '''output''' Support I2S output can be external decoder Internal includes ES9023 own decoded audio output Can connect mobile OTG, recommended player download address http://www.hiby.cd/ Compatible more stable. By professional PCB full posts, precision parts design. All posts using active low temperature Support millet box, the other boxes are not all tested, compatible with Apple, PC Computer WindowXP / 7/8/10 Float crystal vibration, high-quality optical fiber to ensure 192K transmission performance. Support 24bit / 44.1K, 48K, 88.2K, 96K, 176.4K, 192K, Usb audio input and up to 32BIT 192K audio input onboard three Panasonic gold capacitors, high-precision active crystal oscillator, the latest version of the optimized wiring, better indicators! Output 1: Audio Input with ES9023 High-Precision Decode IC with Internal Drive Circuit High Thrust Output 2: I2S output, can be connected to other DA devices Output 3: SPDIF output! That is a coaxial output and optical output Brand Name:Olive Leaf D/A Converter:CM6631A Model Number: Sound Card USB to I2S DSD Sampling Frequencies:None Outputs:RCA,3.5 mm Material:Metal PCM Word Length:24-bit,32-bit PCM Sampling Frequencies:192 kHz USB Compatibility:IOS,Windows 8,Windows 10,Windows 7 Inputs:USB Type-B,USB Type-A Bluetooth:No Type:Portable BASF Cassette history This page is taken from the forum at tapeheads.net. It is reproduced here with the sole purpose to show the pictures in an easy way. The text is exactly the same. The original thread is located at: https://www.tapeheads.net/showthread.php?t=31379 There are six basic categories of BASF true chrome tapes for compact cassettes: chromdioxid SM 1971-80 are singe layer true chromes, with magnetial properties according to DIN reference tape C401R. 1971-74:  http://www.vintagecassettes.com/basf/basf_files/image5036.jpg 1974-76:  http://www.vintagecassettes.com/basf/basf_files/image5098.jpg 1976-77:  http://www.vintagecassettes.com/basf/basf_files/image5175.jpg 1977-80:  http://www.vintagecassettes.com/basf/basf_files/image5187.jpg (77-79 without "hifi stereo cassette" badge, 79-80 with "hifi stereo cassette") chromdioxid super SM 1977-80 are double layer true chromes with off-standard magnetical properties, still close to C401R, but higher sensitivity and a non-linear frequency range on DIN-aligned recorders: 1977-80:  http://www.vintagecassettes.com/basf/basf_files/image5189.jpg (77-79 without "hifi stereo cassette" badge, 79-80 with "hifi stereo cassette") chromdioxid II SM and Cr Extra II 1980-ca 1993 were single layer true chromes, with magnetial properties according to IEC II reference tape S4592A. 1980-82:  http://www.vintagecassettes.com/basf/basf_files/image5245.jpg 1982-85:  http://www.vintagecassettes.com/basf/basf_files/image5304.jpg 1985-87:  http://www.vintagecassettes.com/basf/basf_files/image5327.jpg 1987-89:  http://www.vintagecassettes.com/basf/basf_files/image5347.jpg 1989-91: http://www.vintagecassettes.com/basf/basf_files/image5367.jpg 1991-93:  http://www.vintagecassettes.com/basf/basf_files/image5387.jpg 1993-95:  http://www.vintagecassettes.com/basf/basf_files/image5417.jpg Cr Super II 1980-ca 1995, as well as Cr Maxima II 1982-ca 1994/95 are double layer true chromes with off-standard magnetical properties, still close to S4592A, but higher sensitivity and a non-linear frequency range on IEC-aligned recorders: S 1980-81: http://www.vintagecassettes.com/basf/basf_files/image5246.jpg S 1981-82:  http://www.vintagecassettes.com/basf/basf_files/image5279.jpg S 1982-84: http://www.vintagecassettes.com/basf/basf_files/image5309.jpg S 1984-85: http://www.vintagecassettes.com/basf/basf_files/image5318.jpg S 1985-87:  http://www.vintagecassettes.com/basf/basf_files/image5329.jpg S 1987-89:  http://www.vintagecassettes.com/basf/basf_files/image5350.jpg S 1989-91:  http://www.vintagecassettes.com/basf/basf_files/image5370.jpg S 1991-93:  http://www.vintagecassettes.com/basf/basf_files/image5390.jpg S 1993-95:  http://www.vintagecassettes.com/basf/basf_files/image5420.jpg M 1982-85:  http://www.vintagecassettes.com/basf/basf_files/image5310.jpg M 1985-87: http://www.vintagecassettes.com/basf/basf_files/image5332.jpg M 1987-88:  http://www.vintagecassettes.com/basf/basf_files/image5352.jpg M 1988-91:  http://www.vintagecassettes.com/basf/basf_files/image5372.jpg M 1991-93:  http://www.vintagecassettes.com/basf/basf_files/image5392.jpg M 1993-95:  http://www.vintagecassettes.com/basf/basf_files/image5422.jpg The last examples of the 1993-95 line-up had already the next generation of tape described below. CE II 1995 until the end: " single-layer chrome/ferric cobalt mix (85%/15%)" (quoted from Wilhelm) with higher sensitivity compared to the older models, magnetical properties close to IEC II reference tape U564W http://www.vintagecassettes.com/basf/basf_files/image5437.jpg CS II and CM II 1995 until the end (plus some 1994 Chrome Maxima II): Double layer tape, the lower layer being the same mixture of ferric cobalt and chrome as in the CE II, and the upper layer pure chrome. Frequency response nearly as flat as a single layer tape, magnetical properties close to IEC II reference tape U564W http://www.vintagecassettes.com/basf/basf_files/image5440.jpg http://www.vintagecassettes.com/basf/basf_files/image5442.jpg With the last series of CS II during the Emtec era, I am not sure what tape they used. All four Maxima Design Editions had the contemporary Chrome Maxima tape. All budget chrome cassettes with different names, such as Chrome Standard II, ReCorD II, Sound (Level) II, the 353 Cr II Live as well as the Disney series and other printed shell promotional cassettes had one of the single layer chrome tapes, either the old Chrome Extra II or the new CE II formulation. The Chrome II Super _Quality_ was specially made for Lidl discounter stores Despite having the "Super" shell, I am not sure whether they had single layer CE II or double layer CS II tape inside: 1995-97:  http://www.vintagecassettes.com/basf/basf_files/image5484.jpg 1997-2002:  http://www.shizaudio.ru/audio/data/media/109/BASF-EMTEC_Chrome_Super_Quality_II_C90.jpg 24bit vs 16bit, the myth exploded! It seems to me that there is a lot of misunderstanding regarding what bit depth is and how it works in digital audio. This misunderstanding exists not only in the consumer and audiophile worlds but also in some education establishments and even some professionals. This misunderstanding comes from supposition of how digital audio works rather than how it actually works. It's easy to see in a photograph the difference between a low bit depth image and one with a higher bit depth, so it's logical to suppose that higher bit depths in audio also means better quality. This supposition is further enforced by the fact that the term 'resolution' is often applied to bit depth and obviously more resolution means higher quality. So 24bit is Hi-Rez audio and 24bit contains more data, therefore higher resolution and better quality. All completely logical supposition but I'm afraid this supposition is not entirely in line with the actual facts of how digital audio works. I'll try to explain: When recording, an Analogue to Digital Converter (ADC) reads the incoming analogue waveform and measures it so many times a second (1*). In the case of CD there are 44,100 measurements made per second (the sampling frequency). These measurements are stored in the digital domain in the form of computer bits. The more bits we use, the more accurately we can measure the analogue waveform. This is because each bit can only store two values (0 or 1), to get more values we do the same with bits as we do in normal counting. IE. Once we get to 9, we have to add another column (the tens column) and we can keep adding columns add infinitum for 100s, 1000s, 10000s, etc. The exact same is true for bits but because we only have two values per bit (rather than 10) we need more columns, each column (or additional bit) doubles the number of vaules we have available. IE. 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024 .... If these numbers appear a little familiar it is because all computer technology is based on bits so these numbers crop up all over the place. In the case of 16bit we have roughly 65,000 different values available. The problem is that an analogue waveform is constantly varying. No matter how many times a second we measure the waveform or how many bits we use to store the measurement, there are always going to be errors. These errors in quantifying the value of a constantly changing waveform are called quantisation errors. Quantisation errors are bad, they cause distortion in the waveform when we convert back to analogue and listen to it. So far so good, what I've said until now would agree with the supposition of how digital audio works. I seem to have agreed that more bits = higher resolution. True, however, where the facts start to diverge from the supposition is in understanding the result of this higher resolution. Going back to what I said above, each time we increase the bit depth by one bit, we double the number of values we have available (EG. 4bit = 16 values, 5bit = 32 values). If we double the number of values, we halve the amount of quantisation errors. Still with me? Because now we come to the whole nub of the matter. There is in fact a perfect solution to quantisation errors which completely (100%) eliminates quantisation distortion, the process is called 'Dither' and is built into every ADC on the market. Dither: Essentially during the conversion process a very small amount of white noise is added to the signal, this has the effect of completely randomising the quantisation errors. Randomisation in digital audio, once converted back to analogue is heard as pure white (un-correlated) noise. The result is that we have an absolutely perfect measurement of the waveform (2*) plus some noise. In other words, by dithering, all the measurement errors have been converted to noise. (3*). Hopefully you're still with me, because we can now go on to precisely what happens with bit depth. Going back to the above, when we add a 'bit' of data we double the number of values available and therefore halve the number of quantisation errors. If we halve the number of quantisation errors, the result (after dithering) is a perfect waveform with halve the amount of noise. To phrase this using audio terminology, each extra bit of data moves the noise floor down by 6dB (half). We can turn this around and say that each bit of data provides 6dB of dynamic range (*4). Therefore 16bit x 6db = 96dB. This 96dB figure defines the dynamic range of CD. (24bit x 6dB = 144dB). So, 24bit does add more 'resolution' compared to 16bit but this added resolution doesn't mean higher quality, it just means we can encode a larger dynamic range. This is the misunderstanding made by many. There are no extra magical properties, nothing which the science does not understand or cannot measure. The only difference between 16bit and 24bit is 48dB of dynamic range (8bits x 6dB = 48dB) and nothing else. This is not a question for interpretation or opinion, it is the provable, undisputed logical mathematics which underpins the very existence of digital audio. So, can you actually hear any benefits of the larger (48dB) dynamic range offered by 24bit? Unfortunately, no you can't. The entire dynamic range of some types of music is sometimes less than 12dB. The recordings with the largest dynamic range tend to be symphony orchestra recordings but even these virtually never have a dynamic range greater than about 60dB. All of these are well inside the 96dB range of the humble CD. What is more, modern dithering techniques (see 3 below), perceptually enhance the dynamic range of CD by moving the quantisation noise out of the frequency band where our hearing is most sensitive. This gives a percievable dynamic range for CD up to 120dB (150dB in certain frequency bands). You have to realise that when playing back a CD, the amplifier is usually set so that the quietest sounds on the CD can just be heard above the noise floor of the listening environment (sitting room or cans). So if the average noise floor for a sitting room is say 50dB (or 30dB for cans) then the dynamic range of the CD starts at this point and is capable of 96dB (at least) above the room noise floor. If the full dynamic range of a CD was actually used (on top of the noise floor), the home listener (if they had the equipment) would almost certainly cause themselves severe pain and permanent hearing damage. If this is the case with CD, what about 24bit Hi-Rez. If we were to use the full dynamic range of 24bit and a listener had the equipment to reproduce it all, there is a fair chance, depending on age and general health, that the listener would die instantly. The most fit would probably just go into coma for a few weeks and wake up totally deaf. I'm not joking or exaggerating here, think about it, 144dB + say 50dB for the room's noise floor. But 180dB is the figure often quoted for sound pressure levels powerful enough to kill and some people have been killed by 160dB. However, this is unlikely to happen in the real world as no DACs on the market can output the 144dB dynamic range of 24bit (so they are not true 24bit converters), almost no one has a speaker system capable of 144dB dynamic range and as said before, around 60dB is the most dynamic range you will find on a commercial recording. So, if you accept the facts, why does 24bit audio even exist, what's the point of it? There are some useful application for 24bit when recording and mixing music. In fact, when mixing it's pretty much the norm now to use 48bit resolution. The reason it's useful is due to summing artefacts, multiple processing in series and mainly headroom. In other words, 24bit is very useful when recording and mixing but pointless for playback. Remember, even a recording with 60dB dynamic range is only using 10bits of data, the other 6bits on a CD are just noise. So, the difference in the real world between 16bit and 24bit is an extra 8bits of noise. I know that some people are going to say this is all rubbish, and that “I can easily hear the difference between a 16bit commercial recording and a 24bit Hi-Rez version”. Unfortunately, you can't, it's not that you don't have the equipment or the ears, it is not humanly possible in theory or in practice under any conditions!! Not unless you can tell the difference between white noise and white noise that is well below the noise floor of your listening environment!! If you play a 24bit recording and then the same recording in 16bit and notice a difference, it is either because something has been 'done' to the 16bit recording, some inappropriate processing used or you are hearing a difference because you expect a difference. G 1 = Actually these days the process of AD conversion is a little more complex, using oversampling (very high sampling frequencies) and only a handful of bits. Later in the conversion process this initial sampling is 'decimated' back to the required bit depth and sample rate. 2 = The concept of the perfect measurement or of recreating a waveform perfectly may seem like marketing hype. However, in this case it is not. It is in fact the fundamental tenet of the Nyquist-Shannon Sampling Theorem on which the very existence and invention of digital audio is based. From WIKI: “In essence the theorem shows that an analog signal that has been sampled can be perfectly reconstructed from the samples”. I know there will be some who will disagree with this idea, unfortunately, disagreement is NOT an option. This theorem hasn't been invented to explain how digital audio works, it's the other way around. Digital Audio was invented from the theorem, if you don't believe the theorem then you can't believe in digital audio either!! 3 = In actual fact these days there are a number of different types of dither used during the creation of a music product. Most are still based on the original TPDFs (triangular probability density function) but some are a little more 'intelligent' and re-distribute the resulting noise to less noticeable areas of the hearing spectrum. This is called noise-shaped dither. 4 = Dynamic range, is the range of volume between the noise floor and the maximum volume. Source: head-fi.org Comments: ) The Nyquist theorem does not include amplitude quantization meaning infinite resolution, so it doesn't discuss quantization effects at all. ) There is no audio system in the world giving more than 20 clear bits of signal due to resistance and semiconductor noise chracteristics. ) You cannot "recreate" a single thing by dithering, just make it sounding more natural to the ears, especially when using noise shaping filters for the dither signal. ) It's not true ADC's do any dithering. Some of them do some lowpass filtering with noise shaping involved when delta-sigma type which happens not for the dithering purposes but for the signal itself. ) You cannot increase dynamic range by dithering. ) It's not dynamics killing people and affecting hearing but sound pressure with the given numbers of 140dB = pain, 160~180dB = death, respectively. You can listen to the signal with the 144dB dynamics not exceeding safe sound pressure limits, just set the volume appropriately. Sure, you won't hear the bottom of your dynamic range then. Answers: True. True. Most people believe that their 24bit DAC is actually a 24bit DAC, just marketing I'm afraid. True. Dithering is just a process which should be used whenever a quantisation or re-quantisation is performed, to convert quantisation errors into un-correlated noise. This one is not true. All ADCs use dither. Some 24bit ADCs use self-dither, in other words because the digital noise floor is so low (-144dB) the noise generated by their own internal components is enough to dither, but one way or another, they all dither. Also, all ADCs use a low-pass brick wall filter (anti-alias filter). Noise-shaped dither is not and should never be used in an ADC or when mixing. As the recorded channels are mixed the re-distributed noise is summed and can cause problems. The only time noise-shaped dither should be applied is during the last quantisation process. This usually means when converting the 24bit master from the recording studio into 16bit for CD release. Sort of true. In an absolute sense CD has 96dB dynamic range, however if we move the noise that is down at the -96dB level to areas of the hearing spectrum where we are less sensitive (for example below 60Hz or above 12kHz). This gives a perceived improvement of dynamic range for 16bit. Bob Katz, the leading expert, reckons that about 120dB is the perceived dynamic range achievable with today's dithering technology. True. Though of course by turning down your amp and not hearing the quietest sounds, then you are not hearing all the detail or the whole dynamic range, so it rather defeats the whole purpose of more dynamic range (more bits) in the first place. Pulseaudio settings for audiophiles Pulseaudio is usually installed with default options to make it work with most hardware. But settings can be tuned for better sound-quality. Adjust the following settings in your daemon.conf: resample-method = soxr-vhq avoid-resampling = yes flat-volumes = no high-priority = yes realtime-scheduling = yes default-sample-channels = 2 default-sample-rate = 96000 alternate-sample-rate = 48000 default-sample-format = float32le The two sample rate settings can be adjusted to suit your hardware configuration. Also the sample-format can also be u8, s16le, s16be, s24le, s24be, s24-32le, s24-32be, s32le, s32be float32le, float32be, ulaw, alaw. resample-method can be trivial speex-float-0 speex-float-1 speex-float-2 speex-float-3 speex-float-4 speex-float-5 speex-float-6 speex-float-7 speex-float-8 speex-float-9 speex-float-10 speex-fixed-0 speex-fixed-1 speex-fixed-2 speex-fixed-3 speex-fixed-4 speex-fixed-5 speex-fixed-6 speex-fixed-7 speex-fixed-8 speex-fixed-9 speex-fixed-10 ffmpeg auto copy peaks soxr-mq soxr-hq soxr-vhq SOX audio tool Quick Reference Guide generate file Generate 1 second of white noise. sox -n output.wav synth 1 noise Generate a 1-second sine tone. sox -n output.wav synth 1 sine 440 Generate a 10-second sine sweep file. sox -n output.wav synth 10 sine 0:20000 Exponential sine sweep sox -n -r 44100 sine-sweep.wav synth 10 sine 5/22050 play Play synthesized audio. play -n synth sine 440 trim 0 1 gain -12 Play sine verbose 24 bits /=exponential play -V -n -b 24 -r 48000 synth 10 sine 20/20000 play -V -n -b 24 -r 48000 synth 10 sine 20/20000 vol -50dB And then ARTA: Fs (Hz): 192000 FFT: 4096 Wnd: FlatTop Avg: Peak Hold calibration tones Play 30 tones at once, for frequency adjustment of equipment etc. play -r 192000 -V -n synth 300 sin 20 sin 25 sin 31.5 sin 40 sin 50 sin 63 sin 80 sin 100 sin 125 sin 160 sin 200 sin 250 sin 315 sin 400 sin 500 sin 630 sin 800 sin 1000 sin 1250 sin 1600 sin 2000 sin 2500 sin 3150 sin 4000 sin 5000 sin 6300 sin 8000 sin 10000 sin 12500 sin 16000 sin 20000 remix 1-31 1-31 where: 192000 is the samplerate, if your card supports it 300 is number of seconds - This results in the following spectrum: If you want to generate the file yourself, use: sox -r 192000 -V -n "31 frequencies.flac" synth 300 sin 20 sin 25 sin 31.5 sin 40 sin 50 sin 63 sin 80 sin 100 sin 125 sin 160 sin 200 sin 250 sin 315 sin 400 sin 500 sin 630 sin 800 sin 1000 sin 1250 sin 1600 sin 2000 sin 2500 sin 3150 sin 4000 sin 5000 sin 6300 sin 8000 sine 10000 sin 12500 sin 16000 sin 20000 remix 1-31 1-31 It will create a 300-seconds FLAC file with the 31 tones called "31 frequencies.flac" modify Reduce level by 12dB sox speech.wav output.wav gain -12 Crop to the first 1 second of the file. sox speech.wav output.wav trim 0 1 Reverse the contents. sox speech.wav output.wav reverse Normalise the contents to 0dBFS. sox speech.wav output.wav norm Equaliser (-6dB @ 100Hz, -24dB @ 8000Hz) sox speech.wav output.wav bass -6 100 treble -24 8000 Add room modelling reverb. sox speech.wav output.wav reverb 50 50 100 Trim digital silence from start and end. sox input.wav trimmed/output.wav silence 1 0.1 0 1 0.1 0 - sox infile outfile gain -n normalises to 0dB, and sox infile outfile gain -n -3 normalises to -3dB. effects chorus effect: A typical delay is around 40ms to 60ms; the modulation speed is best near 0.25Hz and the modulation depth around 2ms. For example, a single delay: play guitar1.wav chorus 0.7 0.9 55 0.4 0.25 2 -t Two delays of the original samples: play guitar1.wav chorus 0.6 0.9 50 0.4 0.25 2 -t 60 0.32 0.4 1.3 -s A fuller sounding chorus (with three additional delays): play guitar1.wav chorus 0.5 0.9 50 0.4 0.25 2 -t 60 0.32 0.4 2.3 -t 40 0.3 0.3 1.3 -s compand The following example might be used to make a piece of music with both quiet and loud passages suitable for listening to in a noisy environment such as a moving vehicle: sox asz.wav asz-car.wav compand 0.3,1 6:-70,-60,-20 -5 -90 0.2 The transfer function (`6:-70,...') says that very soft sounds (below -70dB) will remain unchanged. This will stop the compander from boosting the volume on `silent' passages such as between movements. However, sounds in the range -60dB to 0dB (maximum volume) will be boosted so that the 60dB dynamic range of the original music will be compressed 3-to-1 into a 20dB range, which is wide enough to enjoy the music but narrow enough to get around the road noise. The `6:' selects 6dB soft-knee compand-ing. The -5 (dB) output gain is needed to avoid clipping (the number is inexact, and was derived by experimentation). The -90 (dB) for the initial volume will work fine for a clip that starts with near silence, and the delay of 0.2 (seconds) has the effect of causing the compander to react a bit more quickly to sudden volume changes. general --multi-threaded | --single-threaded By default, SoX is `single threaded'. If the --multi-threaded option is given however then SoX will process audio channels for most multi-channel effects in parallel on hyper-threading/multi- core architectures. This may reduce processing time, though sometimes it may be necessary to use this option in conjuction with a larger buffer size than is the default to gain any benefit from multi-threaded processing (e.g. 131072; see --buffer above). PipeWire Quick Reference Guide qpwgraph pw-top pw-cat - Play and record media with PipeWire pw-dump pw-dsdplay pw-play pw-record Use METAFLAC to edit Flac Tags Install FLAC package, then metaflac will be present. #root@moode:/mnt/SDCARD# metaflac --set-tag ARTIST="David Axelrod" holythursday.flac  #root@moode:/mnt/SDCARD# metaflac --set-tag TITLE="Holy Thursday" holythursday.flac #metaflac --list my_music.flac Installing audio plugins IMPORTANT FOR VST INSTALLATIONS: If you deploy plugins as a subdirectory of your VST2 directory, the subdirectory should contain substring 'lsp-plugins'. Otherwise plugins won't find the VST2 core library. Please notice that '~' means user's home directory. For Linux/FreeBSD The usual directories for LADSPA are:  * /usr/lib/ladspa  * /usr/local/lib/ladspa  * /usr/lib64/ladspa  * /usr/local/lib64/ladspa  * ~/.ladspa   The usual directories for LV2 are:  * /usr/lib/lv2  * /usr/local/lib/lv2  * /usr/lib64/lv2  * /usr/local/lib64/lv2  * ~/.lv2 The usual directories for LinuxVST are:  * /usr/lib/vst  * /usr/local/lib/vst  * /usr/lib64/vst  * /usr/local/lib64/vst  * ~/.lxvst  * ~/.vst The usual directories for JACK core library are:  * /usr/lib  * /usr/local/lib  * /lib  * /usr/lib64  * /usr/local/lib64  * /lib64 The usual directories for JACK binaries are:  * /usr/bin  * /usr/local/bin  * /bin  * /usr/sbin  * /usr/local/sbin  * /sbin   The usual directories for CLAP are:  * /usr/lib/clap  * /usr/local/lib/clap  * /usr/lib64/clap  * /usr/local/lib64/clap  * ~/.clap DCC Knosti liquid Ik heb er nu een paar schoongemaakt in de knostie met een zelfgemaakt mengsel bestaande uit: Water uit de supermarkt, H10 van de fotograaf en Ajax allesreiniger. Had geen alcohol in huis dus denk probeer het eens zonder. Plaat schoon en zo goed als alle tikken en narigheid is weg. Geen stof aan de naald. Ga het maar eens een poosje zonder de alcohol doen. Dit gaat vooralsnog ook prima.Op 1 liter water 5ml H10 en en een paar druppels Ajax voor het ontvetten. Gaat het ook lekker van ruiken ;) Wat zit er dan voor rotzooi in regenwater? Ik gebruik het al meer dan 35 jaar zonder probleem. Een scheut gedenatureerde alcohol erbij doet de verdamping (drogen) versnellen. Maar wie platen nat speelt wil dat niet. Ben deze week maar eens begonnen met het reinigen van mijn oudste platen. Met een eigen brouwsel (1 deel 97% alcohol, 2 delen demi-water, en een druppel afwasmiddel op een halve liter) in een plantenspuit vinyl besproeien en schoonmaken met een microvezeldoekje. Droog deppen met keukenpapier. Naast de eigen Knosti vloeistof heb ik ook de reinigingsvloeistof van QS audio gebruikt. Ook prima, ik heb geen voorkeur voor één van de twee. QS laat geen pluisje aan de naald achter na de eerste keer afspelen, maar daar had ik sowieso geen problemen mee. Voor mij is het meer een kwestie van beschikbaarheid. Je schijnt de vloeistof ook heel goed zelf te kunnen aanmaken, van gedestilleerd water, isopropylalcohol en een drupje afwasmiddel, maar de juiste verhouding weet ik zo gauw niet. Ik heb me daar nog niet aan gewaagd. Inmiddels heb ik mijn hele collectie LP's (circa 300) zo behandeld. Mijn huidig recept is 1 teiltje met lauwwarm water, 2 theelepels Dreft Platinum en 1 eetlepel glansspoelmiddel. Als wasdoekje gebruik ik een zijdeachtige brillenschoonmaakdoek. Aleen een richting die de richting van de groven volgt en van binnen naar buiten werken. Naspoelen onder koud stromend water, even uit laten druipen en drogen met een hele zachte, niet-pluizende katoenen doek en klaar is kees. In gebieden met hard water zou ik aqua destillata aaraden. Een goed alternatief is het condenswater uit je wasdroger opvangen en dat filteren. Dan heb je (ook) bijna puur water zonder zouten die een neerslag n je groeven zouden kunnen geven. I have a Knosti antistat and I think it is the best thing since sliced bread - though the problems with their fluid i entirely agree, i had exactly the same problems :evil: After much experimentation i now use a 50/50 mix of (99 percent pure) Isoppropyl alchohol and de-ionised water in the Knosti, very slowly turn the record in only one direction 2 or 3 times without stopping, the results are fantastic, no crackles I've stopped using isopropanol in my cleaning solution, now it's just pure water and 20mls of a detergent from the lab at work (sorry don't know the name of it) it looks like PhotoFlo but not as strong. After a round or 7 each way in the trough I then rinse under the tap (thanx CL) with the spindle still attached. Then its another 3 complete rotations each way in the trough with a pure water and 2mls detergent solution and then a dry in the rack. I leave it as long as necessary to dry. The detergent in the final round is a wetting agent to stop beading. The more rotations in each direction the better the clean I have found, especially for second hand records. Once in a while I find a record needs a second clean this sometimes works and is definitely good for your mental condition if it works. :D DCC tapes when is the tape/datapath ok? "A much better indication for the quality of the datastream is the TAPE BLOCK COUNTER ffff. If the counter is reset every minute the signal processing path should be ok. One minute of uninterrupted error-free data blocks gives a count of 1200. In case of too high error rates (frequent resets) check the signal flow DCC Head -> read amp -> DEQ -> DDSP (esp. RDMUX)" initialiseren van een DCC tape / initialize a DCC tape Initialiseren van nieuwe bandjes, of een DCC bandje nieuw opnemen: DCC450: REWIND, then APPEND and REC/MUTE to start. DCC600: REWIND, then press APPEND. DCC730 & 951: REWIND, then REC SELECT/PAUSE. Initialize new DCC tapes, or make DCC tapes new again: DCC600: REWIND, then press APPEND DCC730 & 951: REWIND, then REC SELECT/PAUSE probleempiep Na het onderzoeken en oplossen van het gepiep van een dcc cassette, https://nl.wikipedia.org/wiki/Digital_compact_cassette , ben ik eens gaan onderzoeken waarom een dcc cassette vastloopt in een dcc speler. Aanleiding was de koop op marktplaats van een dcc 600 recorder met een aantal opneembare en voorbespeelde dcc cassettes. De verkoper werd gek van het gepiep en vastlopen van de recorder. Hij had destijds zelfs een nieuw loopwerk bij philips op de kop kunnen tikken. Voor hem vrij makkelijk want hij werkte bij philips. Dit loopwerk heeft hij vervangen en wat bleek: de bandjes bleven vastlopen. Uiteindelijk staat heel de boel hier op de werkbank. Hij deed de hele boel van de hand van ellende. cassettes De koppen en het loopwerk heb ik om te beginnen maar eens goed gereinigd. Om zeker te weten dat de recorder goed werkt, heb ik mijn eigen cassettes gedraaid. Deze liepen niet vast. Dan moet het aan de cassettes liggen, zou je zeggen. openen Om te beginnen maar eens een opneembare cassette geopend. Dit is niet een eenvoudige zaak, daar je eerst het veertje moet ontgrendelen van het schuifbare metalen klepje. De twee helften zitten vervolgens in elkaar geklikt. Deze zijn met wat voorzichtig beleid wel uit elkaar te halen. Bij het openen van de cassette komt een folie los die je los kunt verwijderen. De twee helften liggen naast elkaar op de werkbank. Nu zien we het verschil tussen een gewone analoge cassette en een digitale cassette. Beiden hebben natuurlijk een viltje in het midden van de tape die de band tegen te kop duwt. Deze veroorzaakt vaak een pieptoon, dit is bekend. viltje Aan de zijkanten links en rechts achter de witte rollertjes zit bij een dcc echter ook een viltje. Deze zorgen voor een stabielere loop van de digitale tape. Bij analoge cassettes zijn deze viltjes niet aanwezig. Deze viltjes zijn meteen ook het probleem van het vast lopen van de cassettes. Dus niet het viltje wat tegen de kop duwt!.De recorder krijgt de tape hier niet doorheen geduwd. Dus loopt hij vast. Ook dit geeft een piep toon.Deze viltjes hebben schijnbaar een vette substantie omdat een weinig gebruikte voorbespeelde dcc dit probleem ook geeft. reinigen Na verloop van tijd als je de cassettes lang niet gebruikt geven deze viltjes een vette plek achterop de tape. Dus precies achter het viltje, zowel links als rechts.(linker en rechter viltje) Dit kun je zien door de tape een klein beetje uit de cassette te trekken. Een donker plekje op de tape blijft achter. Met videospray cleaner 90 en een wattenstaaf kun je deze plek verwijderen. Alcohol is lastig omdat deze toch wat achter laat op de tape.Je mag dus niets meer op de tape zien. Hoe langer je de tape niet gebruikt des te vetter wordt die plek achter het viltje. weer in elkaar Na reinigen heb ik de cassette weer in elkaar gezet. Het in elkaar zetten is ook wat lastig omdat ook het veertje wat het metalen beschermkapje bedient op de juiste manier terug moet worden gezet. Als de cassette in elkaar zit, blijkt dat het vastlopen over is. Hetzelfde probleem ontstaat met voorbespeelde cassettes, ook hier plekjes achterop de tape als je de cassette lang niet gebruikt hebt. Bij mijn eigen cassettes heb ik dit probleem ook aangetroffen, daar ik niet regelmatig dcc cassettes draai en dus cassettes lang laat liggen zonder dat deze zijn teruggespoeld. conclusie Conclusie van dit verhaal is: Laat dcc cassettes niet te lang liggen als deze niet zijn teruggespoeld. Spoel je ze terug dan ontstaat dat probleem niet omdat dan de aanlooptape achter de viltjes zit. De viltjes zitten net links en rechts achter de witte geleiderol. Al mijn cassettes met dat probleem heb ik kunnen reinigen. Je hoeft natuurlijk niet steeds de cassette uit elkaar te halen. Tape kun je ook zo uit de cassette halen met een pincet. Het uit elkaar halen van de cassette was bedoeld om te kijken hoe dat probleem ontstaat. wit vs. bruin Ik heb inderdaad het idee dat de witte viltjes eerder piepen dan de bruine viltjes. Het lijkt erop dat witte viltjes meer vuil oppikken dan de zwarte. De bruine zijn ook van een harder materiaal gemaakt lijkt het en daardoor minder bevattelijk voor vuil. Ik heb hier ook cassettes liggen met zwarte viltjes, deze zijn echt harder.Bij de productie dus al wijzigingen doorgevoerd. De viltjes in de cassette welke links en rechts zitten zijn ook wit. Ik heb zelf alle cassettes teruggespoeld naar het begin of het einde. Het vastloop probleem deed zich bij mij dus ook voor. Een nieuwe dcc had ik eenmaal tot halverwege gedraaid. Daarna niet meer gebruikt en na een lange tijd zat deze dus ook vast. Je zag precies aan de achterkant op de tape een vetplek zitten van het viltje dat niet vuil was. Deze geven dus standaard af op de tape. Ze doen dit niet na korte tijd, en na langere tijd zie je de tape op die plek wat golven. Zowel voorbespeeld als opneembare dcc,s hebben hier last van. Waarschijnlijk is dit ook de reden dat veel eigenaren met een dcc951 problemen krijgen met het apparaat. En trouwens ook de dcc 900. Een dcc 951 geeft dan aan dat de kop gereinigd moet worden, terwijl het probleem in de cassette zelf zit. Voordat je denkt dat een drukrol versleten is of snaar slecht is, moet je zeker weten dat de cassette welke je in het apparaat stopt , goed is. Piepgeluiden in het middelste viltje geven daardoor ook de nodige problemen. je denkt al snel dat dat piepen uit de recorder komt. Philips heeft deze problemen niet meer opgelost, omdat het systeem in 1996 gestopt is. Alleen zag je dat er zwarte ipv witte viltjes gebruikt werden.Ze hebben deze problemen waarschijnlijk op het laatst ook waargenomen. Mooi voor ons deze problemen verder op te lossen. Aandrukviltje bij de kop schoonmaken met IPA en wattestaafje, ook wat opruwen en pluizig maken, zodat er geen plakkende laag onstaat. Bron: http://forum.mfbfreaks.com/ DCC history Peter W. Mitchell: The public debut of Philips's digital compact cassette (DCC) was the biggest event at the 1991 CES in Las Vegas, which began with a large press conference that drew a crowd of about 200 audio journalists. Philips executives laid out the logic underlying the DCC's design, how it will be marketed, and the technical principles of its operation. Except for an awkward moment when a cassette-well door on a prototype DCC deck refused to open, the presentation was persuasive and the free buffet supper—featuring sinfully delicious lamb chops—was the best I've tasted at any CES press conference in years. During the next two days audio writers were invited upstairs in smaller groups of 10 to 20, to ask questions and hear the system in a hotel-room setting. There are three stories in the DCC debut: what it sounded like, how it works, and how its performance was refined. Of these, the last proved to be the most surprising. Sound A DCC recording uses only a fourth as many bits per second as a CD thorugh bit-rate reduction (footnote 1). Since the DCC is intended to be a mass-market product, and since the CD has already been accepted as the mass-market standard for sound quality, Philips set up a demonstration whose aim was to illustrate that the DCC provides CD-quality sound in a smaller and conveniently home-recordable package. For each group of a dozen or so audio writers, Philips played a comparison of CD vs DCC sound through a system of good but not ultimate quality, a system that might retail for between $5000 and $10,000. The signal from the CD player was fed to a preamp and also to a prototype DCC encoder/decoder. By the time the system goes into production the DCC processing circuits will have been shrunk to a handful of ICs that will fit within a standard-size cassette deck; at present the circuits fill a cube about 24" on each side. The DCC signal was encoded for recording and then decoded for playback, but was not actually recorded on tape. (In principle, that should not affect the comparison, since the system has enough error-correction capacity to handle normal tape imperfections.) The output from the DCC unit was precisely matched in level to that from the CD, and a switch enabled an A/B comparison between the CD "original" and the encoded/decoded DCC "copy." How did it sound? "It was not obviously flawed." This is an audiophile reviewer's cover-your-butt way of saying that he didn't hear any difference but doesn't want to go out on a limb and say that the sound was identical, because he doesn't want fellow reviewers to think him cloth-eared. In fact, most of the people I spoke with afterward heard no difference in most of the comparisons. Some of the invited writers challenged the system with their favorite CDs of music or test signals. Ironically, as I will explain later, two widely used test signals, pink noise and pure sinewave tones, are very useful for detecting faults in analog and conventional (linear PCM) digital products but are especially easy for the DCC to handle. The most challenging test may be simple music, a signal that has energy at several frequencies but also has empty spaces in the spectrum, in which the ear might hear low-level artifacts. One writer felt that the DCC's noise floor was not quite as low as that of an optimally dithered CD (notably the low-level glide tone on the CBS test disc). Others felt that the DCC sounded slightly brighter and coarser than the CD. However, when the A/B switch was operated there was a switching transient (a short noise burst) and an audible time offset caused by slight delays in DCC encoding which might have produced an illusion of a sonic difference even where there was none. I remained after a group demo and was treated to an additional private A/B comparison in which I selected CDs that I thought would be particularly revealing, sat in the optimum stereo-center seat, and operated the A/B switch myself. I soon became convinced that I heard a slight difference (B was brighter than A). Then, after I deliberately lost track of the switching order, I found it easy to persuade myself that A sounded slightly brighter than B—indicating that my perceptions were indeed being affected by the switching transient. Of course, conditions were not conducive to the most critical evaluation. The all-Philips playback system (Philips electronics and four-way Philips speakers) did not seem as transparent and revealing of subtle differences as, for example, a system based on Apogee Stage speakers. And while the Philips personnel thoughtfully switched off the room's noisy airconditioning unit during the comparisons, the ambient noise level was still higher than in most homes. So I tried to think of a way to enhance the audibility of any subtle flaw the DCC might have. Two possibilities immediately came to mind. First, since the DCC uses only a fourth as many bits as the CD, its handling of low-level hall ambience might be impaired, especially if the compressed digital bitstream is not optimally dithered to minimize quantizing distortion. Second, one historically popular way of boosting the apparent information-carrying capacity of a limited channel is to use matrix encoding. For example, stereo FM radio produces an illusion of decent sound by combining mono FM (an L+R signal having inherently wide dynamic range and fairly low distortion) with an L–R subcarrier that has high distortion and limited range. The poor quality of the L–R subcarrier is often masked by the much louder L+R portion of the composite signal. Similarly, the analog LP began as a low-distortion, wide-range medium that used purely lateral modulation for its mono (L+R) information; then it was converted to stereo by adding an L–R stereo "difference" signal as a vertical modulation that has much higher distortion and a very limited dynamic range. This is mathematically equivalent to modulating the two walls of the LP groove at 45° with separate left and right signals. But the vertical/horizontal picture leads to a clearer understanding of the medium's limits. In the early days of the stereo LP there were great debates in hi-fi magazines about whether the improved perspective of stereo was valuable enough to offset the new distortions (pinch effect, etc.) that became a problem when the stylus had to detect deliberate vertical modulation. Historically, one of the most important aspects of an LP mastering engineer's job was to artfully limit the vertical excursion of the stylus in ways that didn't obviously compromise the sound. It was crucially important to make sure that the cutting stylus could never rise completely out of the lacquer (producing a discontinuous groove) or penetrate all the way through to the bottom of the acetate and scrape the glass or metal backing plate that the lacquer was coated on. The stereo LP, even more than stereo FM, succeeded because most of the time the L+R (horizontal) portion of the signal is much louder than, and effectively masks the flaws of, the L–R (vertical) stereo difference portion of the composite modulation. There's a very easy way to discover how well any audio medium handles low-level ambience, and also to learn whether it uses matrix encoding to mask its limitations: listen to the L–R portion of the signal separately, without the louder L+R portion. In this mode one can also listen for variations in the level or timbre of the L–R signal, which may be caused by the two channels going partly or wholly out of phase at high frequencies—a common fault in phono pickups, analog tapes (both cassette and quarter-track open-reel), and early CD players. In stereo playback this fault causes problems in soundstage imaging. In FM broadcasting it causes severe dulling of the highs (and, in severe cases, comb-filter coloration) when a stereo broadcast is heard in mono. Anyone who still has the classic Apt/Holman preamp can do this test easily: just rotate the Mode knob from Stereo to the L–R position. To achieve an equivalent result, I asked the Philips folks to disconnect the speaker wires at the back of the amplifier and connect the wires from one speaker to the left and right "hot" terminals, so that the speaker would reproduce just the L–R portion of the stereo signal. After a brief hesitation while they wondered if this connection might risk the amplifier's stability, they proceeded to do it. I was impressed, and a little surprised, by this cooperative attitude. It suggested that although they hadn't tried this test themselves, the Philips people were so confident of the DCC's sound quality that they didn't expect to be embarrassed. Their implied vote of confidence was doubly impressive because by the time I suggested this rewiring of the demo system, the next group of audio writers had arrived—and when they heard about the proposal they were as eager as I to hear the result. This group included Michael Riggs, now an editor at Stereo Review, and Ken Pohlmann, whose informed writings on digital audio are published in several big-circulation consumer and pro audio magazines. If the L–R test revealed a flaw in the DCC, the bad news would be published far and wide. Not to worry; the DCC passed with flying colors. To challenge it, I chose a nicely recorded Philips CD of Schubert songs for solo voice and piano. In the L–R mode the soprano voice, imaged precisely in the center of the stereo stage, was substantially canceled out, dropping in level by about 20dB. The direct sound of the piano also declined in level. With most of the low-frequency and midrange body of tone removed, what remained were high-frequency harmonics and all of the recorded hall ambience, including the delicate tail end of the reverberation. Recall that the DCC encoder was still handling the full stereo signal; the L–R subtraction took place only at the amplifier output. As we listened alternately to the CD and to the DCC "copy," even the L–R mode did not reveal any clear difference in timbre, ambience, or low-level resolution. Of course, a CD is not itself an absolute standard of sound quality, especially since most available CDs were recorded through the Sony PCM-1610 or 1630—digital processors with sonic limitations of their own. At the show the Philips folks mentioned that the next phase in refining the DCC encoder would involve comparisons with new CDs that were recorded with "20-bit equivalent" oversampling delta-sigma A/D converters—for instance, the UltraAnalog (formerly dbx) converter used by Chesky (footnote 2) and the Bitstream A/D that is now used in some Japanese studios. To sum up: the DCC, while using only a fourth as many bits as the CD, successfully duplicates average-quality CD sound. If it isn't an exact match, the disparity is about on the same scale as the differences among CD players. We don't know yet whether it may prove unsatisfactory by high-end audiophile standards (footnote 3), or whether it will sound as good as the very best R-DATs. But it is better than it needs to be for the mass market—and is light-years ahead of the analog cassette that it is destined to replace. Technology The impetus to develop DCC came not from a technical breakthrough but from a marketing problem. When Japanese manufacturers launched the R-DAT format five years ago, they proclaimed it the digital successor to the analog cassette, just as the CD is supplanting the LP. An interesting idea, but is it likely? At the high end of the home recording market, and among hi-fi hobbyists who are actively involved in taping, the answer is yes. It's worth remembering that Japanese hi-fi gear is developed first for the domestic market and is then sold to the rest of the world. Japanese audio hobbyists love tape recording. (Open-reel tape machines continued to flourish in Japan long after they died in every other market.) And because Japanese hi-fi buffs like to assemble their own compilations of favorite music, and to fool around with sound effects, the first DAT recorders were designed to facilitate easy digital dubbing from CDs. In early R-DAT brochures the new format was presented as the heart of a complete living-room digital studio for every hi-fi enthusiast. Of course, when major record companies understood this, they launched a legal and political war against DAT that is still going on. Even assuming that R-DAT might someday capture the entire market for living-room tape decks, is that where the analog cassette market is? Not at all. This year Americans will buy more than 30 million cassette mechanisms, but only 3 million will be AC-powered living-room decks. The other 90% operate in motion: headphone portables, radio/cassette boomboxes, and car stereos. The majority of these are play-only; even those equipped for recording (eg, boomboxes and some headphone portables) are used mainly to play prerecorded tapes. In the US there are as many cassette mechanisms as people. The average household has three. Worldwide, a billion cassette mechanisms are in use. This year people will buy 180 million new machines and a billion prerecorded music cassettes (fig.1). Another billion and a half blank cassettes are sold annually, many for non-musical applications (telephone answering machines, taping college lectures, journalist interviews, talking books for the blind, et al). Fig.1 Worldwide recorded and blank media market, 1988 (© Bureau Contekst). Philips invented the cassette format in 1963 and may be more aware than anyone else of its worldwide dominance as the leading carrier of recorded music. Looking at the numbers, Philips concluded that regardless of how successful the R-DAT might be among hi-fi hobbyists and living-room component systems, these account for only a tiny share of the market. There is no possibility that R-DAT could be the true digital successor to the analog cassette. It faces two fundamental obstacles: cost and software. Sony and Panasonic have done an impressive job of shrinking the price of DAT recorders from $2000 to $800. But how much lower can they go? A DAT mechanism is a miniature helical-scan VCR, with many precision parts in exacting alignment. If mass-production is the key to getting the price down, consider camcorders; they sell in the millions and still cost $500 to $1000 apiece. Yet CD players sell for as little as $99, while analog cassette mechanisms add less than $50 (often only $20) to the retail price of a product. My teenage niece has a $180 boombox that contains AM/FM radio, cassette, and a CD player that proved surprisingly competent when I connected its Line outputs to my brother's stereo component system. Could R-DAT conceivably have any future in this application, or in $40 headphone portables? Not a chance. As for software, copying discs onto tape is OK for hobbyists, but most people don't want to bother. They just want to buy music in a convenient package and enjoy it. There are tens of thousands of software titles available on analog cassette but only a few hundred on DAT. Sony recently announced plans to double the production capacity for prerecorded DAT at its Indiana factory. But that will still be mainly for Sony Classics and a few independent labels that want to produce DAT recordings for sale. Sony hasn't even managed to persuade the pop-music division of CBS Records (which it owns) to release DAT versions of Michael Jackson and Bruce Springsteen hits, much less the other large record companies (RCA, Warner, Arista, et al) that remain united in their opposition to DAT. Even if record companies accept DAT, recordings are duplicated by dubbing in real time onto racks of Sony DAT recorders, a slow and costly process. If enough demand developed, they could adopt Sony's $100,000 Sprinter, a high-speed duplicator that uses a magnetic "contact printing" process to transfer the magnetic pattern from a master tape to DAT duplicates. Still, while CDs now cost only a buck apiece to press, blank DAT cassettes cost about $5 in large quantities. Each DAT is a miniature videocassette, with a hinged door and a dozen internal parts, and the tape is a metal-powder formulation that is expensive to manufacture. The bottom line is that prerecorded DATs (if record companies were willing to produce them) would always cost substantially more than the equivalent CD. That's enough to limit their appeal and probably rules out R-DAT as the digital successor to the analog cassette. Philips concluded that the digital replacement for the analog cassette would have to be cheap enough to be a true mass-market product, be amenable to economical high-speed duplication, be supported by major record companies, and be readily adaptable to various physical forms (headphone portables, slot-load car players, and AC-powered home decks). So, rather than designing new mechanisms from the ground up, Philips decided to base the design of the DCC on analog cassette mechanisms that manufacturers around the world already produce in vast quantities at very low cost—from the $20 headphone portable made of plastic parts to the slot-load car player and the high-performance dual-capstan home deck. Many analog cassette mechanisms can be converted to DCC use by substituting a different head and adding a few small parts. The DCC cassette has the same exterior dimensions as the analog cassette, runs at the same 1 7/8ips tape speed, and has the same 90-minute running time (45 minutes per side). 120-minute tapes will also be produced, mainly to offer home recordists the same 2-hour capacity as R-DAT. But home recording is a relatively minor part of the product concept. More importantly, DCC cassettes have the same playing time as the CD (80-plus minutes), so prerecorded DCC tapes can be mass-produced from the same masters that CDs are cut from. As a bonus, the DCC offers the mass market a painless transition to the digital age: DCC machines will also play the dozens of analog cassettes that every home already possesses. (Compatibility and worldwide standards have always been high priorities at Philips.) The idea is that when your present cassette machine wears out and you go to buy a new one, you'll be tempted to upgrade to a DCC machine that will play all your old tapes and also provide CD-quality sound from new tapes. The analog playback will include Dolby-B since that is the world standard for prerecorded cassettes. Other manufacturers may include Dolby-S decoding, but Philips is reluctant because Type S is not a major factor in the prerecorded cassette market. (That may change by the time DCC decks arrive in 1992. Two large US tape duplicators recently converted their machines to Dolby-S encoding, which is said to be playback-compatible with Dolby-B.) Of course, there are important differences between analog and digital cassettes. Analog cassettes have a bulge along one edge to accept the heads; DCC cassettes are uniformly slim, so it is easy to carry several in a shirt pocket. Analog cassettes are symmetrical, since in many machines you flip the cassette over to access the Side B tracks. All DCC machines will use dual-capstan auto-reverse mechanisms, so the DCC cassette is never turned over. It has reel hubs and access holes only on the bottom; the flat top face is covered by a big label. A standard DCC machine will record and play digital tapes but won't record analog cassettes; it is playback-only. Reason: it is bidirectional, and adding dual erase and record heads for both directions would be expensive for a capability that few people would use. For those who still want to record analog cassettes (for friends, or to play in the car), Philips suggested that the most cost-effective solution would be a dual-well dubbing deck, DCC in one well and analog record/play in the other. Several years ago, when Apple introduced the first Macintosh computers, Steve Jobs began a presentation to the Boston Computer Society by tossing a handful of then-new 3.5" mini-floppy disks into the audience. Computer buffs, familiar with the vulnerability of conventional floppies, were startled and impressed by this cavalier behavior—especially when Jobs demonstrated that the mini-disk didn't need a protective envelope but could be carried bare in a shirt pocket. The plastic disk housing contains a sliding shutter that seals the case shut when not in use, protecting the disk from fingerprints and dust. Philips borrowed the same great idea for the DCC. Unlike analog cassettes, which are open along one edge and vulnerable, the digital cassette has a sliding metal shutter that protects the tape when it's not in the machine—forever eliminating awkward and easily broken "jewel box" carriers. Prerecorded DCC tapes will come in a transparent sleeve with program notes, but away from the living room you'll carry only the self-protected cassette. This fumble-free convenience is enough to make DCC the digital medium "for the rest of us." The sliding shutter doesn't add much to the cost of the DCC cassette; I paid only 39 cents for the 3.5" disks I use in my computer. According to Philips, the metal-powder tape required for R-DAT is costly, not amenable to conventional high-speed duplication, and unstable at the high temperatures that may occur in a closed car on a summer day. So the DCC was designed from the ground up to use low-cost tape, specifically video-format chromium dioxide, which is produced in vast quantities for VCRs. A Philips spokesman mentioned that with CrO2 tape and a housing that is not much more complex than an analog cassette, blank DCC cassettes may be priced only slightly higher than premium-grade analog tapes, around $5. (For comparison, blank R-DATs cost $8 to $15 at retail.) CrO2 tape can reliably record wavelengths as short as one micron (1;um or one-thousandth of a millimeter). At a tape speed of 4.75cm/s, this is equivalent to a maximum frequency of 47.5kHz. Since each cycle corresponds to two bits (a 1 followed by a 0), the corresponding data rate per track is 95,000 bits per second (bps). By recording on eight narrow tracks, the DCC records a total of about 760,000bps. About half (384,000bps) are audio data; the rest are used for error-correction coding. For comparison, the data rate in the CD is 1,408,000bps (44,000 samples/s x 16 bits/sample x 2 channels). Thus the data rate in the DCC is about one-fourth that of the CD. Since the sampling rate is the same, the DCC records an average of only four bits per sample. Low-level noise is added to "dither" the signal and thereby minimize any quantizing distortion. In addition to the eight tracks of digital data, a ninth track will contain subcodes, timing codes, a table of contents, and (optionally) up to 400 characters per second of text, which may be shown either on a built-in display or a separate video screen. The text could be used for song lyrics, program notes (synchronized with the music), multilingual opera librettos, background stories about the recording sessions, etc. Philips proposed a similar text display nine years ago for the CD, but the idea was ignored by record companies and most manufacturers, perhaps because it would require extra work to prepare the text for encoding with the signal when the master recording is cut. (Most CDs don't even have indexing of the sections of a symphonic movement, which takes relatively little effort to implement.) By monitoring the subcode track during fast-wind, a DCC player can cue quickly to the beginning of a song, display timings, play songs in any order, and generally provide the same operating conveniences as a CD or R-DAT. Cueing to another song may require a few seconds, as with R-DAT, instead of the near-instant cueing that CD provides. Since all DCC tapes will be recorded in auto-reverse format, the last song on Side B will be in the same section of tape as the first song on Side A, requiring only an auto-reverse maneuver (reverse the direction of tape motion and rotate the head 180°) to access it. If you're making your own recordings you'll have to plan ahead so that the automatic reverse at the end of the tape won't leave a two-second gap in the middle of a movement. (In this respect R-DAT is superior, with up to two hours of continuous, uninterrupted recording time.) The DCC combo head has gaps for the nine digital tracks in its upper half, plus two gaps for analog tracks in its lower half. When recording or playing Side B, the head is flipped to place the digital gaps on the bottom (fig.2). When you load an analog cassette, sensing pins automatically flip the head to put the analog gaps on top for side A. (Incidentally, since DCC tapes don't turn over, Philips wants to call the two tape directions the A and B "sectors" rather than "sides.") Fig.2 The DCC digital/analog tape head, showing the reversible disposition of digital heads 0–8 and analog heads A1 and A2. The tiny head gaps are formed by a lithographic thin-film process similar to that used to create microscopic layered circuits and conductive paths in silicon IC chips. Philips took advantage of this to devise a clever trick. First, the nine digital recording gaps are formed in a row, each 0.19mm high so that tracks of that width will be recorded on the tape. A thin insulating layer is added, and digital playback gaps are formed on top. Each is aligned with the center of the corresponding record gap but is only 0.07mm high. Result: since the short playback gaps read less than half of each recorded track, the tape can be misaligned relative to the head by as much as 0.12mm (plus or minus 0.06mm) and still play correctly. With this much tolerance for slop, DCC machines can use ordinary cassette mechanisms; costly machined parts and precise alignment won't be needed. (Incidentally, although the recording and playback gaps are separate, you can't use them to monitor the signal off the tape while making a recording. The gaps are so close together that magnetic coupling occurs between them.) A DCC machine communicates with the outside world through a standard Sony/Philips digital interface (S/PDIF), using the same 16-bit PCM codes as a CD player or R-DAT. Thus its digital input accepts 16-bit data from a CD player, and its digital output produces normal 16-bit data that can be fed to an outboard D/A converter or may be recorded on any conventional digital device (R-DAT, recordable CD, et al). In principle, you could even record live music on a DCC deck and use its digital output to master a CD. As in consumer R-DAT decks, digital dubbing is regulated by an SCMS circuit that allows any CD to be copied digitally onto tape but codes the copy so that it cannot be further copied. The analog input of a DCC deck is converted to PCM code by a normal 16-bit A/D converter, and the playback stage uses a conventional 16-bit D/A to generate its analog output. The choice of A/D and D/A circuits (conventional multibit, MASH, Bitstream, or whatever) will be up to each manufacturer of DCC machines. The heart of the DCC is a complicated block of circuitry called the PASC (Precision Adaptive Sub-band Coding), which a few years ago would have required a roomful of computer power and hours of processing time to do its job—which is to compress the incoming 16-bit digital data to an average of 4 bits per sample for recording and, during playback, to re-expand the 4-bit data to 16-bit output codes. As explained in the January 1991 issue, the encoding is done by a microprocessor programmed with information about the psychoacoustic limits of human hearing. The goal is to provide accurate coding of sounds we hear but not to waste bits coding information that we can't hear. The incoming 16-bit data stream is fed to a digital filter that divides the audio frequency range into 32 sub-bands, analyzes the signal content in each band, and uses only enough bits to encode the portions of the signal that are above the human threshold of hearing. The threshold varies with frequency (the Fletcher-Munson effect). A person with normal hearing can hear 2kHz at a very low 0dB sound-pressure level, but at 30Hz you can't hear anything softer than about 60dB spl anyway. More important, the threshold at each frequency varies from moment to moment according to the strength of sounds at neighboring frequencies ("masking"). Thus when an 80dB tone is present at 1kHz, your hearing threshold at 2kHz rises temporarily from 0 to about 50dB spl. Then, as long as the 1kHz tone is present, the system can safely discard any information below the 50dB level in the 2kHz sub-band—which may include the second harmonic of the 1kHz tone. If you wouldn't have heard it anyway, you won't notice its absence. Music, unlike noise, usually contains energy at only a few harmonically related frequencies. So at any given moment many of the 32 bands are likely to contain little or no energy. That frees many unused bits that can be assigned to provide more accurate coding in the bands that contain strong signals. This dynamic reallocation of bits between sub-bands plays a large role in the reduction of the overall bit rate. When fed a pure tone at a single frequency, nearly all of the available bits can be assigned to the sub-band containing this frequency, coding it with very low distortion. Conversely, when tested with pink noise, which contains equal energy in every band, all bands are active and only a few bits can be used for each; but since it is noise, high accuracy at each frequency isn't important. The most challenging test signal might be music of moderate complexity, exercising enough bands to use up the system's bit capacity while leaving enough "open space" in the sound that any faults could be heard. Final development According to Philips, the basic engineering design of the DCC system was completed in 1989. With a normal product the engineers would then measure a prototype to certify its performance with test signals, and would listen to it to make sure there was nothing obviously wrong. But since the DCC's encoding varies dynamically according to masking thresholds and other psychoacoustic criteria, its performance cannot be judged with conventional test signals. In the final analysis its sound quality can only be judged by ear. It sounded OK to the engineers, but masking thresholds may vary, and it is well known that some people hear sonic faults more acutely than others do. Moreover, golden-eared listeners aren't just born; they are trained (or train themselves), learning what to listen for and improving their skill with long practice. So, to evaluate whether the DCC could match the sound of CD, the designers turned to the trained listeners who are employed by the quality-control ~department at Philips Records (footnote 4). Listening to test signals and music, they did hear differences. So for the past two years Philips has been refining the PASC encoder, submitting it to listening panels, computer-analyzing the listening data with statistical programs to distinguish real differences from random chance and delusion, and fine-tuning the encoder again. Reportedly, after the latest round of refinements even the company's most golden-eared listeners can no longer distinguish the DCC from a CD source. Thus one of the largest electronics companies in the world found itself in the unusual position of fine-tuning the performance of an important new product in the same way the smallest cottage-industry audiophile designers do—by listening to it, with recorded music. And the company's engineers found themselves in the slightly humbling position of having to improve a product's design because non-engineers said it didn't sound quite right. The digital compression scheme has an interesting consequence. A DCC recorder accepts 16-bit PCM codes from a CD player, shrinks the bitstream to an average of four bits per sample for recording, then in playback regenerates 16-bit PCM output codes. The playback may sound the same as the original input signal, but the codes are not the same: the playback is a "cleaned up" version of the signal. The PASC processing puts the signal on a diet, stripping away the low-level musical harmonics that were below the dynamic masking threshold. Thus the playback signal, no matter how faithfully it may duplicate the original sound, is not a clone of the original code. You may recall that when the record industry launched its legal war to prevent the R-DAT from being sold in the US, one of its alleged concerns was that, if consumers acquired an unlimited ability to make "clone" copies of the digital code in a CD, record companies would effectively lose control of their expensively produced digital master recordings. Hypothetically, pirates with R-DATs could swamp the market with perfect clone duplicates of master tapes, depriving the record companies of their economic base. Of course, this idea contained more paranoia than reality; anyway, for what it's worth, the DCC doesn't make digital clone copies. That may help to explain why some record companies, at least, have expressed support for the DCC and will be mass-producing prerecorded DCC tapes for sale. Of course, the strongest support for DCC came from Philips's own PolyGram group of companies (Philips, DG, Archiv, Decca/London, L'Oiseau-Lyre, ECM, and Polydor), promptly followed by the EMI group (Capitol/Angel). BMG (RCA, Ariola, Arista) expressed interest in DCC but, like the rest of the record industry, wants Congress to impose a royalty tax on blank tape before the company will support any new recording medium. However, the momentum that seemed to be building in Congress to consider a royalty law was aborted by the Iraq war. Congress intends to devote itself to matters deemed more important than a squabble between branches of the entertainment industry. Philips has acquired two major partners in the DCC project. In the US, Tandy Corp. announced last fall its intent to be the first licensed manufacturer of DCC machines and tapes. Tandy is already North America's largest electronics manufacturer and, through its 7000 Radio Shack stores, our biggest retailer of consumer electronics. The company is expanding its role still further by launching new store chains (Video Concepts, The Edge in Electronics) and by being first with new technologies like notebook computers and the DCC. The decks and their digital circuits will be produced at Tandy's computer factory in Texas, while the tapes will come from Tandy's (formerly Memorex's) magnetic media plant in California, a major producer of computer disks as well as audio and video tapes. In Japan, Matsushita (parent of Technics and Panasonic), which has had a technology-sharing agreement with Philips for over a half-century, has also signed up for DCC. In fact, according to a Philips executive, Philips and Matsushita will be "co-licensors" of the DCC, in the same way that Sony and Philips are co-licensors of the CD. Companies that want to make DCC decks or tapes will have to get a license, pay royalties to Philips or Matsushita, and make sure that their products conform to the official design standard. In contrast, standards for R-DAT were developed by agreement among several manufacturers and are unenforceable. Example: since Congress failed to pass an SCMS/DRM law last year, the inclusion of SCMS in R-DAT decks is essentially voluntary, enforced only by Japan's Ministry of Trade and Industry. Companies in Korea and Taiwan are free to make R-DAT decks without SCMS if they wish. But in the case of DCC the SCMS circuit is mandatory; it is a condition of the license. All in all, the introduction of the DCC was the most impressive product launch since the CD, nine years earlier. If record companies get behind it—a crucial if—the DCC has a very good chance of knocking off both the R-DAT and the home-recordable CD as consumer products. Philips appears to have met its goal of combining CD-quality sound with the recordability, convenience, and compact size of the cassette. The first DCC machines probably will be AC-powered home decks and may be priced in the $600 range when they appear next year. By that time R-DAT decks may also be selling for $600, so we could see a brief format war between the two digital tape systems. But it won't last long; second- and third-generation DCC machines, notably play-only portables, car decks, and DCC boomboxes, could drop to the $200 level within a few years. Audiophiles and tape recording hobbyists may continue to prefer R-DAT, if only for its longer uninterrupted recording time, but DCC is likely to prove the true successor to the analog cassette. It's what my sister—and everyone else—will want. The largest remaining uncertainty is whether enough record companies will produce prerecorded DCC tapes to make it a mass-market success. At the moment the record companies that have committed to the DCC are all European. If the Recording Industry Association of America were to decide that the SCMS offers no protection and all digital recording formats must be fought until a royalty tax is passed, the US launch of DCC could be nearly as slow and painful as that of R-DAT. If DCC gets the support of major record companies, and cuts the ground out from under R-DAT, Sony still has an alternative up its corporate sleeve: the tiny Digital Memo Recorder (DMR), a simpler and cheaper mini-DAT that uses stamp-size cassettes. The truly interesting format war between digital tape systems may feature DCC vs DMR. Stay tuned.—Peter W. Mitchell Read more at https://www.stereophile.com/content/pasc-philips-dcc#xQLcVirM1owdzIfw.99 DCC FAQ FAQ - Digital compact cass recorder GENERAL INFORMATION . 900 Series ''Digital Convenience'' DCC recorder . Direct digital recording . Plays also Compact Cassettes . Full 18-bit system . Turbo drive . Title recording . Microphone input . ''System Intelligence'' bus AUDIO TAPE DECK DIGITAL DCC (playback) Sample frequencies: 44.1 kHz, Wow and Flutter : Quartz Crystal Precision DIGITAL DCC (recording, line in) Sample frequencies: 44.1 kHz, DIGITAL DCC (recording, digital/optical in) Sample frequencies: 32 kHz (satellite Tuner e.g.) 44.1 kHz (CD) 48 kHz Perfect digital recording AUDIO/SOUND DIGITAL DCC (playback) Frequency range : 20Hz-20kHz Amplitude linearity : � 0.05 dB S/N ratio (A-weighted): � 105 dB (1 kHz) Dynamic range : � 100 dB (1 kHz) THD+N : � 90 dB (10 kHz) Channel Separation : � 110 dB (1 kHz) DIGITAL DCC (recording, line in) Frequency range : 20Hz-20kHz Amplitude linearity : � 0.1 dB S/N ratio (A-weighted): � 100 dB (1 kHz) Dynamic range : � 92 dB (1 kHz) THD+N : � 85 dB (1 kHz) Channel Separation : � 100 dB (1 kHz) ANALOGUE CASSETTE (playback only) Frequency range : 40Hz-16kHz (CrO2) S/N ratio (A-weighted): 55 dB (CrO2) Dolby B/C : Improvement B: 10 dB Improvement C: 18 dB Signal also supplied to digital outputs Headphone amplifier performance . Load Impedance Range: 32-600 Ohm . Output impedance : 170 Ohm . Output voltage (L+R): Max. 5V Rms . Frequency range : 20-20 kHz Microphone . Microphone impedance Range : 200-2000 Ohm OPERATION/CONTROLS . Remote control RC-5, 20 keys supplied CONNECTIONS Inputs: Analogue : impedance 50 K ohm Digital Coaxial: acc. to IEC 958 Digital optical: TOSLINK Outputs: Analogue : 2V ms Digital Coaxial: acc. to IEC 958 MISCELLANEOUS Dimensions (wxhxd) : 435x90x300 mm Display : 14 characters FTD Material/Finish : Metal and polystyrene Mechanism : 2 motor metal deck RC socket : ESI bus, 2x cinch Tape-speed level : 4.76 cm/sec FREQUENTLY ASKED QUESTIONS PLAYBACK: DCC cassettes Problem: DCC cassettes causing faults (a.o. drop outs, tape salad, clean head). Cause : DCC cassettes outside specification. REMARKS : The used DCC cassette is not according the DCC specification and so NOT released by Philips. (e.g. some of Maxell and Fuji cassettes) It is recommended to use released Philips DCC cassettes only. PLAYBACK: Skipping small part of music Problem: Skipping small part of music of pre-recorded DCC-cassettes after track search Cause : Repositioning problem due to high fast wind/rewind speed. REMARKS : After track search command the DCC does not start exactly at the beginning of a track. First approx. 500 msec. of track are not played back. This problem does not occur when DCC-cassette is played-back normally. This deviation is dependant on the position of the tape; via the reel-tacho signals the movement of the reel is measured not the tape. To reduce this error a compensation is done, based on an average required repositioning within � 0.5 sec. Only in the minus area this short jump could be noticed. This problem cannot be solved. TRACK AND TIME: REMaining time Problem: REMaining time indication is not reliable. Cause : Calculation of remaining time by DCC recorder REMARKS : The DCC recorder starts with defining an estimated total remaining time. After that it calculates the elapsed time by reading total time information of played back tracks. The remaining time left on tape is the estimated playing time of the cassette minus the elapsed time. The remaining time might have a tolerance of about 1 minute. So it might happen that for instance the display shows 'REM TIME 5:38, and yet a music piece of about 4:14 will not fit. TRACK AND TIME: Track and Time information is erased Problem: Track and Time information is erased when adding text information. Cause : Not correct initialized cassette. REMARKS : Sometimes track number and time information is erased when recording text information. When using RENUMBER to reconstruct the track numbering again the missing time information will be misinterpreted as tape end and tape direction is reversed, while renumbering continues on side B. OPERATING: "DUBBING ACTIVE" Problem: Message 'DUBBING ACTIVE' on display of DC951. Cause : Via presets like: source CD and CD SYNCHRO ON the reference for CD dubbing is defined. REMARKS : After actuating REC SELECT/PAUSE key the DCC951 is looking for its preference entry in the Philips 900 series system, with correct ESI BUS connections. When the presets are set to source CD and CD SYNCHRO ON the set is waiting for acknowledge command from CD player. In case other keys are pressed in the meantime the message 'CD DUBBING ACTIVE' is shown as operating error message. If ESI BUS is not connected in the right way the message 'NO CD SYNCHRO' is shown. NOTE: CD SYNCHRO mode can be changed with the PRESETS function as follows: - press PRESETS - press RECORD - by pressing 'wind' or 'rewind' the presetted CD SYNCHRO mode can be switched ON or OFF - press PRESETS to store settings. Only valid for DCC951. OPERATING: AUTO STOP mode Problem: DCC recorder does not stop after last recording when selected AUTO STOP mode. Cause : Auto stop function is wrongly interpreted by user. REMARKS : With the PRESETS function the playback function can be set as soon as a cassette is inserted. With playback set at AUTO PLAY, playback will always be started automatically as soon as the tray has been closed (and cassette is inserted) by pushing the tray by hand or the POWER has been switched ON. With playback set at AUTO STOP, playback will not start automatically. NOTE: To find last recording user should use APPEND to search for the end of the last recording (which was marked when STOP was pressed during recording). APP > or APP < appears. When this position has been found the last 10 seconds will be played back (APPEND PLAY), after which the RECORD PAUSE (REC-P) mode is entered. OPERATING: NO CD SYNCHRO desired Problem: NO CD SYNCHRO desired by user of DCC951. Cause : Function CD SYNCHRO ON is selected in preset. REMARKS : When CD SYNCHRO option is not required by user, or not via ESI BUS connected with other sets from the Philips 900 series system, it should be switched off. This can be done as follows: - press PRESETS - press RECORD - press WIND or REWIND to switch to CD SYNCHRO OFF - press PRESETS to store presets. To use CD SYNCHRO ON presets must be changed by applying above mentioned procedure again and the ESI BUS should be proper connected to other sets in the Philips 900 series system. Only valid for DCC951. OPERATING: Operation of source selector Problem: Operation of source selector is not clear. Cause : IFU does not explain selection of source very clear. REMARKS : After installation of the DCC recorder all input sources should be selected via source preset. This is done as follows: - Press PRESET - By pressing REC SELECT/PAUSE the default CD is indicated on display. By pressing NEXT key the cable connection made with CD player can be selected. By pressing again REC SELECT/PAUSE the next input source (tuner etc) can be selected. Every time again the applied cable connection with source can be selected via the NEXT key. - When all sources (to be recorded from) via REC SELECT/PAUSE and NEXT are selected these presettings are stored by pressing PRESET. Making a recording from one of the sources the latest used source (this setting is also stored by the set) is selected. If another source should be selected this is done as follows: - Press REC SELECT/PAUSE, the default source is already indicated on display (except Microphone). - By pressing REC SELECT/PAUSE again next source is selected. - Subsequently pressing REC SELECT/PAUSE gives the other available sources. Sequence of source selection is CD TUNER AUX1 AUX2 CD TUNER, etc. In case microphone socket has been connected this input source is selected automatically. NOTE: In case a digital recording will be made from CD or AUX as source and no digital connection is made the message: 'CHECK DIG IN' is displayed and one should reconnect digital cable from recorder to source. For more detailed information See the Instructions for Use. A quick reference card for ease of operating is made available: For DCC730 with service code 4822 725 22612 For DCC951 with service code 4822 725 22611 These reference cards contain clear pictographs to operate the DCC recorder. OPERATING: Operate DCC recorder Problem: It is difficult to operate DCC recorde. Cause : DCC recorder is software controlled (play back = CD similar). REMARKS : Correct understandings of the user-recorded tape formats and markers will help customers to make full use of the benefits of the DCC recorder. See also newsletter 63.01. For ease of operationg a quick reference card is made available: For DCC730 with service code 4822 725 22612 For DCC951 with service code 4822 725 22611 These reference cards contain clear pictograms to operate the DCC recorder for every mode. OPERATING: Renumbering Problem: Renumbering not possible when making a new recording at specific location. Cause : In User format is RENUMBER not possible. REMARKS : Before recording first initializing of the tape has to be performed. See also newsletter item 63.01 OPERATING: Music passages are lost Problem: Music passages are lost after renumbering. Cause : 'CONTINUE B' (REVERSE) and 'GO TO START A' (STOP) marker cannot be erased. REMARKS : Markers which are recorded on the tape, control the set in play back mode. This means that in PLAY mode all information recorded on tape behind the 'Continue B' marker or 'Go to Start A' marker is skipped. The recordings behind those markers can only be reached by winding over that marker. OPERATING: Track numbering Problem: Track numbering does not start at number 1 when recording side B. Cause : Per default single Album format is defined. REMARKS : Track numbering starts at side A (when AUTO EDIT ON) directly after the LEAD-IN area with number 1. Track numbering is automatically incremented when recording new tracks and continues on side B. In other words the DCC tape is seen as one single album where one may select a particular track, and it does not matter whether the required track is on side A or B of the tape. If user wants to start track numbering with track 1 on side B to obtain e.g. a dual Album, EDIT function must be performed. When in REC-PAUSE mode: - - press EDIT key to enter the edit mode - select required EDIT function by pressing EDIT several times - press RECORD key to actually edit the tape. Next edit functions are available: - - START NEW SIDE: to start track numbering on side B with track number 1. When restarting of track numbering is required, user must search for last recording on side A, record START NEW SIDE indication. - CONTINUE B: track numbering is continued at side B. - GO TO START A: marks the position where the deck should start winding to the beginning of side A and stop. RECORDING: Analog level Problem: Analog level cannot be reduced until zero using REC LEVEL control. Cause : No analog fade in/out option available. REMARKS : Recording level control is not meant to obtain fade in/out effects for own analog recordings. Typical fade in/out feature is not available on DCC sets. Analog recording level control is meant to be used for adapting input level for analog signals. To obtain real fade in/out effects an audio mixing unit (e.g. SBC5370), connected to AUX - ANALOG IN, should be applied. RECORDING: Clicks are audible Problem: Clicks are audible when interrupting recording with REC PAUSE. Cause : Difference between digital mute (-110dB) and analog silence (>-30dB) can be recognized as click being recorded. REMARKS : By mixing different titles (from e.g. various Vinyl Records) clicks are audible between the analog silence signal of the vinyl recording and the interrupting of the recording with REC PAUSE (digital mute). It is this difference in level between the analog silence and the digital mute (system detects a sudden increase of level) that the DCC recorder records, and is audible as a click during play back at high volume level. RECORDING: Old recordings remain Problem: Parts of old recordings remain after overwriting existing recordings. Cause : Cassette is not initialized correctly before overwriting. REMARKS : When a CD-synchro recording is made on a DCC-tape which was already recorded in the past, the set switches at the estimated end from side A to side B. When playing back this part of the tape first the 'new' music is heard followed by the 'old' music until end of side A and in the beginning of side B. This problem can be prevented by renumbering the tape. NOTE: To overwrite a previous recorded DCC tape press REWIND key more than 0.5 second (set must be in STOP mode). Tape is rewound to the beginning of the tape. By pressing REC SELECT/PAUSE key the LEAD IN portion of about 10 seconds is recorded. Afterwards the set goes to Record Pause mode. When pressing RECORD the recording starts and tape will be completely overwritten. Set 'sees' tape as being new. To record in the middle of an existing track (recording on a specific location) first the location should be searched, than (in STOP mode) press subsequently REC SELECT/PAUSE and RECORD. RECORDING: Track numbering Problem: Track numbering DCC does not match with the track numbering of the source (e.g. when digital copying a Compact Disc) Cause : Track number is automatically increased at end of side A with CD SYNCHRO OFF. REMARKS : At end of side A a CONTINUE B marker is recorded. The DCC standard requires a new track number at the start of side B. This marker is not on the CD, so all recordings from side B have a track number (CD track number + 1). RECORDING: Track numbering Problem: Track numbering does not match with the track numbering of the source (e.g. when analog copying a Compact Disc). Cause : Track number is recorded after an analog silence (signal level below -60dB) for more than 3 seconds and track number is automatically increased at end of side A with CD SYNCHRO OFF. REMARKS : - In AUTO EDIT ON mode a new track number will be written after every silence for more than 3 seconds, where 'silence' is defined as an analog signal level below -60dB. It might happen that a source (Compact Disc) has music pauses for more than 3 seconds within one music number, or pauses between tracks are shorter than 3 seconds. User may edit the track numbering afterwards by CONNECTing or SPLITting TRACKS. By connecting tracks the current and next 'pause' track will be connected and later on recognized as one track. During this action the DCC recorder will erase the START indication of that 'pause' track. By splitting tracks the current track will be split up in two successive tracks. - DCC standard requires a new track number at the start of side B. (See also problem "RECORDING: Writing markers in AUDIO EDIT") NOTE: When tracks have been connected or splitted also a RENUMBER action is necessary to ensure a correct track number sequence. RECORDING: Writing markers in AUTO EDIT Problem: Writing markers in AUTO EDIT mode after more than 3 seconds of silence. Cause : IFU mentions 3 seconds of silence. REMARKS : In AUTO EDIT ON mode the DCC recorder writes new track numbers on the tape when silences (signal level below -60dB) of more than 3 seconds are detected during recording from ANALOG input. The signal level of the source must be below -60dB before DCC system recognizes a music pause. It might happen that during fading out of music, the user perceives a silence but that signal level is not dropped below -60dB. In this case the music pause seems to be much longer than 3 seconds. Note: In AUTO EDIT OFF the DCC recorder will not perform automatic track increment when recording from analog sources. AUTO EDIT is always set to ON when a digital source is connected (via digital sockets). RECORDING: Microphone recording input Problem: Microphone recording input is only Mono Cause : Only Mono microphone pre-amplifier designed. REMARKS : When microphone is connected, the DCC set automatically selects the MONO microphone input. Recording via another source is not possible as long as microphone is connected. When Stereo recording via microphone is required it is recommended to connect microphone(s) to an audio mixing unit (e.g. SBC5370) which must be connected to AUX, ANALOG IN. PLAYBACK: De-emphasis Problem: De-emphasis in DCC player is not functioning after making a digital copy of a Compact Disc. Cause : In PLAYBACK mode the DCC recorder switches de-emphasis ON or OFF dependant to the contents of the system information (SYSINFO). REMARKS : De-emphasis of a DCC recording is only activated in PLAYBACK mode if concerned bit in sysinfo is switched on. This flag is set during recording from digital input. This information is sent from the CD player to the DCC recorder. In play back the DCC recorder switches de-emphasis on or off dependant of the flag setting in sysinfo. Recording via analog input will not set the de-emphasis flag. This is already performed in the CD player via the information in the SUBCODE. Manually on/off switching of de-emphasis by user is not possible. PLAYBACK: CLEAN HEAD Problem: CLEAN HEAD indication Cause : Contaminated head. REMARKS : The special design of DCC-head makes it sensitive for contamination, especially when low quality ACC tape (Fe tape) is used. The applied DCC tape consists of high quality chrome tape, which will not contaminate the head. In order to ensure high quality recording the warning of the CLEAN HEAD indication is displayed according following criteria: - about 8 hours of total playing back time of ACC tape. - 2 channels or more on DCC tape not detected by DCC head for more than 3 seconds. please notice: In case CLEAN HEAD indication was caused by a temporarily bad HEAD-TAPE contact, the message will disappear after pressing the 'TIME' or 'TEXT' key. Philips DCC951 This page is also for the Philips DCC730. They have the same tapemechanism. specs snaren: capstansnaar lengte dubbelgevouwen is ongeveer 150 mm, of iets korter. breedte 3mm, dikte 0,5 mm. straal | radius : 48mm omtrek | circumference : 300mm diameter | diameter: 95mm plat | flat lenght : 150mm een 2e én 3e exemplaar hadden dubbelgevouwen lengte van 155 mm. ladesnaar lengte dubbelgevouwen 98mm, vierkant 1,3mm breed. aandrukrol: 13 x 6 mm as: 2 mm Verder moet je de voeding nakijken, soldeerverbindingen van o.a. de spanningsregelaars. aansluitingen bij de tulpstekers. Er kunnen printbreuken zijn. english belt capstanbelt lenght folded flat approx. 150 mm, or a little bit shorter. Width 3 mm, thick 0,5 mm. traybelt length folded flat 98 mm, square 1,3 mm width, pinch roller: 13 x 6 mm, axis: 2 mm. Check power supply; solderings check connections at rca audio plugs. possible board fractures. initialize a tape Initialize new tapes, or make them new again: For DCC730 & 951: REWIND, REC SELECT/PAUSE track numbering According to the DCC specification, on side B a new track number starts. So, when recording from CD, and a track overflows from side A, a new tracknumber will be generated at the start of side B. Therefor, all tracknumber on side B will be the original numbering +1 clean head is displayed 'Clean Head' is displayed when 8 hrs of ACC is played 2 channels or more on DCC tape not detected by DCC head for more than 3 seconds. In case CLEAN HEAD indication was caused by a temporary bad head-tape contact, the message will disappear after pressing TIME or TEXT key. Enter Service Test Program Press 2 keys simultaneously PLAY+STOP and switch power on. ERROR NUMBER SURVEY These numbers will be displayed sometimes when an error occurs. The numbers have the following meaning: 00: No error 01: Deck failed The requested command could not be executed because of a malfunctioning of the mechanics. 02: Tray blocked This error is issued when the tray has been blocked, although the tray might be moving out again due to this fact. The blocked indication will hence occur very short in the tray status message and could be missed. 03: Tray pulled open During normal operation the tape drive module has sensed that the tray loader is forced to the open state by the user. 04: Invalid parameter The parameter going with the last received command is unknown or out of range. 05: No cassette The command can not be executed since there is no cassette loaded. 06: Digital Audio input but of lock or missing carrier During recording from a digital input, no input signal is detected. When continuing the recording, undefined data will be recorded which may lead to unpredictable audio during playback. The DDU module will refuse to continue the recording. 07: Digital Audio input has Professional class (unsupported) During recording from a digital input, a professional source may be detected which is not supported by the DDU module, hence the module will refuse to record from this source. 08: Digital Audio input has non-audio format During recording from a digital input, the input data may contain computer data instead of audio. The DDU module will refuse to continue the recording. 09: Copy right protection violation (SCMS) During recording from a digital input, which contains user audio data but which is copyright protected, the DDU module will refuse to continue the recording. 10: Internal DCC chip error There has an error occurred within the DCC chips on the DDU digital module. When this error persists over a longer period of time, please consult your nearest service officer. 11: Record attempted on write protected tape A record or auxiliary record or record-pause command is issued while the loaded cassette is write protected or is an A00. The DDU module will refuse to record on such a tape. 12: Non existent search target The target to search for does not exist on the currently loaded cassette. e.g. search for track number 20 while the tape only contains 12 tracks. 13: Invalid command received The command which was received is not allowed in this context. 14: Setting not allowed This error message will be returned when the DDU module is performing a TOG search and a next_previous_count is downloaded. 15: Command overrun The DDU module has received to many state changing commands in a row to handle. This error occurs whenever a command is received while another command is still waiting for execution. The DDU module will not store a queue of received commands. 16: Signature not yet loaded The record command will only be accepted by the DDU module after the setmakers signature has been loaded. This will make it possible to identify the recording set of each DCC cassette. 17: Unreliable TOC During the process of TOC search the DDU module found out that the contents of the TOC does not match the contents of the tape. The search command should be repeated using relative search. 18: Search target could not be found The requested search target was valid but could not be found, e.g. a direct track search after track number 5 on a super-user tape while track number 5 was removed by after-reoording, or an append search on a full tape. 19: Marker writing not allowed A request for a marker can be rejected because of the fact that the last recorded marker is not yet 3 tape frames past or a marker is currently being written or the tape is write protected. Also when the requested marker is out of context (lead_in A on side B or reverse maker on side B this error occurs. 20: Not Used. 21: No track numbers on this tape Attempt to do a track search on a tape with notrack numbers, e,g, search track number 10 on a non-super user tape. Note that a search for track number 1 will always be honoured. 22: No proper super-user tape The renumber function could not detect a marker on this super user tape or the renumber function was called on a user tape. 23: No TOC available A direct access search has been requested on a super—user tape which does not have a valid TOC. This search requests can not be honoured. 24: Sector not allowed Not allowed to change sector in this mode or a sector is requested which is not on the tape, e.g‘. sector D on a 2-sector tape. 25: No user characters loaded An attempt to record user characters while these are not yet loaded. 26: Clean head The reproduction of the audio is bad due to dirt on the head. The user should clean it. 27: Marker may not be removed Attempt to erase a temporary reverse marker or the first start marker on the tape. 28: No search from virgin A search action can not start from a virgin tape position. 29: Tape drive does not respond This error occurs when the digital module can not communicate with the tape drive module. 30: Tape fault on tape broken/blocked. 31: Power down detected by tape drive module. Philips DCC170 snaar/belt: 63 mm OR 67mm x 0.6 OR 0,8mm drdcc: We have tried all sizes. I believe that the 0.7 is the better option. Ralf Philips DCC900 Specs snaren | belts 3 snaren: capstan, loader, tray. capstan platte snaar maat 73mm x 3,7mm x 0,6mm. loader ladesnaar groot straal| radius :27mm omtrek | circumference : 170 mm diameter | diameter : 54 mm platte lengte | flat lenght : 85 mm tray ladesnaar klein straal| radius :14mm omtrek | circumference : 88 mm diameter | diameter : 28 mm platte lengte | flat lenght : 44 mm Philips FW68 This is a full stereo set, containing a DCC and ACC cassette deck, tuner, cd player and amplifier. belts and rollers Analog Compact Cassette (ACC) Deck Capstan belt The belt on the ACC deck is 103 mm flat length, so: straal | radius : 33 mm omtrek | circumference : 206 mm diameter | diameter : 66 mm platte lengte | flat length : 103 mm Width: 4 mm. Thick: 0,5 mm. square belt The square belt is 65 mm flat lenght, so: straal | radius : 21 mm omtrek | circumference : 130 mm diameter | diameter : 41 mm platte lengte | flat length : 65 mm Width: 1 mm. Pinch roller Digital Compact Cassette (DCC) deck The mechanism is the same as in the Philips DCC951 and DCC730. ???? <= need to check this, not really sure about that. Capstan belt capstanbelt lenght folded flat approx. 110 mm, or maybe a little bit shorter. straal | radius : 35 mm omtrek | circumference : 220 mm diameter | diameter : 70 mm platte lengte | flat length : 110 mm Width 3 mm. Thick 0,5 mm. Pinch roller pinch roller: 13 x 6 mm, axis: 2 mm. CD player Tray loading belt straal | radius : 13 mm omtrek | circumference : 80 mm diameter | diameter : 25 mm platte lengte | flat length : 40 mm Tip: recording from other sources And here is a top tip: you can indeed record from ACC -> DCC, and also from tuner -> DCC or tuner -> ACC, but you should not use those small preset buttons for recording. You proceed as follows: Suppose you want to record from ACC -> DCC. Insert the ACC and the empty DCC, rewind the DCC, press REC PAUSE on the DCC, RECORD will appear on the display, the player will start writing LEAD IN etc., please wait for it, then press PLAY on the analog deck and on PLAY of the DCC. A recording is made from the ACC to the DCC. Same for recording from Tuner to ACC or DCC: press REC PAUSE, press TUNER, and press PLAY. This works for both the analog deck and the digital deck. Good luck with it! Dell Latitude D610 DCC-Studio Specifications Dell™ Latitude™ D610 User's Guide Processor Processor type L1 cache L2 cache External bus frequency System Information System chipset Processor Side Data bus width DRAM bus width Processor address bus width Flash EPROM Graphics bus PCI bus PC Card CardBus controller PC Card connector Cards supported PC Card connector size Data width (maximum) Memory Memory module connector Memory module capacities Memory type Minimum memory Maximum memory Ports and Connectors Audio Infrared Mini PCI Modem Network adapter Parallel Serial S-video TV-out USB Video Communications Modem: Type Controller Interface Network adapter Wireless Video NOTE:  Your Dell™ Latitude™ D610 computer has both integrated and discrete video options. Video type: Data bus Video controller Video memory LCD interface TV support Color output Video type: Data bus Video controller Video memory LCD interface TV support Color output Audio Audio type Audio controller Stereo conversion Interfaces: Internal External Speaker Internal speaker amplifier Volume controls Display Type (active-matrix TFT) Dimensions: Height Width Diagonal Maximum resolutions: XGA SXGA+ Operating angle Viewing angles: Horizontal Vertical Pixel pitch: XGA SXGA+ Power consumption (panel with backlight) (maximum): XGA SXGA+ Controls Keyboard Number of keys Layout Touch Pad X/Y position resolution (graphics table mode) Size: Width Height Track Stick X/Y position resolution (graphics table mode) Size Battery Type Dimensions: Depth Height Width Weight Voltage Charge time (approximate): Computer on Computer off Operating time Life span (approximate) Temperature range: Operating Storage AC Adapter NOTE:  The 90-W AC adapter is optional and may not ship with your computer. Types Input voltage Input current (maximum) Input frequency Output current: 90 W 65 W Output power Rated output voltage Dimensions: Height Width Length Weight (without cables) Temperature range: Operating Storage Physical Height Width Depth Weight: With travel module With CD drive Environmental Temperature range: Operating Storage Relative humidity (maximum): Operating Storage Maximum vibration (using a random-vibration spectrum that simulates user environment): Operating Storage Maximum shock (measured with hard drive in head-parked position and a 2-ms half-sine pulse): Operating Storage Altitude (maximum): Operating Storage Philips DCC600 Onderhoud van een Philips DCC600: rechthoekige ladebovenklep eraf schroeven (ligt OP de cassette. TORX 6 nodig) en dan kun je bij de kop: goed schoonmaken met wattenstaafje en IPA. Let op: kop is zeer fragiel. rechthoekige bovenlade heeft 3 witte/gele nylon wieltjes: schoonmaken. de 2 kleine aandrukrolletjes eruit wippen en schoonmaken met IPA en daarna een nacht in verzadigde afwas laten weken. de 2 snaren vervangen: lade en loopwerk. de snaar van de lade is vierkant: 80 mm diameter en 1 a 1,3 mm dik. de snaar van het loopwerk is 3,5x0,5x150mm (breedte x dikte x lengte platgedrukt). de 2 capstans reinigen (IPA). loopvlak (zwart, op de 2 wielen) van de capstan-riemen schoonmaken. loopwerk smeren. eventueel druppeltje olie in de motoren. Het soldeerwerk van de voeding nalopen. -servicemode aanzetten: dolby - play - en dan rec/pause indrukken. Laat o.a. dropouts zien. -Er kan een probleem met de voeding zijn, losse pootjes van spanningsregelaars -Vaak is de print zekering van t3.15ma op het main board defect. Deze gaat erdoor omdat de oude snaar vastplakt aan 1vd vliegwielen. -Het LDU-1000 loopwerk zit in de DCC300, DCC380, DCC600 en de DCC450. -Zie ook de Repair database onderaan de pagina == Modifications Looking at the manual...... PSU board Caps 2215, 2216, 2217 replace with same voltage larger uF caps. These are the PSU reservoir caps. Prob replace 2211 2213 with same value uF. Probably limited by physical size here. Something like Panasonic FR or FC or TSUP if they fit. Digital board On the digital board, replace all the elcos with OsCon SEPC solid polymer much higher uF like 470uf 6.3v unless they are doing a specific job other than PSU. Check with the manual. Analogue output stage 2257, 2258 2259 2260 are elco's in the signal path - replace with 4.7uf film caps like WIMA MKS2 (tiny with 5mm lead spacing) and very good. Opamp 7305 replace with dual opamp of choice (LME49720 is my choice) and see if you can get some local elco's on the PSU pins 2351 & 2352 in the feedback loop with 470 pf Silver mica Obviously do a bit at a time and listen in between........ These mods are suggested based on general experience modifying similar equipment and not the DCC600 directly...... Maintenance of a Philips DCC600: unscrew the rectangular drawer top cover (is located on top of the cassette, TORX 6 required) and then you can access the head: clean well with cotton swab and IPA. Note: head is very fragile. rectangular top drawer has 3 white / yellow nylon wheels: clean. flip out the 2 small pressure rollers and clean with IPA and then soak overnight in saturated detergent. replace the 2 strings: drawer and running gear. the belt of the drawer is square: 80 mm diameter, or 130 mm flat, and 1 mm thick. the belt of the running gear is 3.5x0.5x150mm (width x thickness x length flat). clean the 2 capstans (IPA). clean the tread path (black, on the 2 wheels) of the capstan belts. lubricate running gear. maybe drop of oil in the engines. Check the solderings in the power supply board. -potential problem with the Power Supply. Voltage regulators with loose legs. Resolder. -often the fuse t3.15ma on the mainboard is defect. engage servicemode To engage servicemode : dolby - play - and then press rec/pause. Shows the dropouts etc. OFFICIAL PHILIPS REPAIR DATABASE: MODEL: DCC600 SYMPTOM: The display does not light up at all. CURE: Check the -30V. If not available, check T7201 (4822 130 41327). MODEL: DCC600 SYMPTOM: Totally inoperative. CURE: Check solder joints of mainsswitch S1204. MODEL: DCC600 SYMPTOM: Totally inoperative. (No display and no functions) CURE: Check the main and front uP. MODEL: DCC600 SYMPTOM: No tape transport. The capstan motor does not run. CURE: Check for short circuit in the deck motor PCB. MODEL: DCC600 SYMPTOM: Digital no sound, analog weak, reading and winding all the time. CURE: Clean the head. MODEL: DCC600 SYMPTOM: DCC sound interrupting. CC plays O.K. CURE: Check Dig. PCB (4822 214 33899). MODEL: DCC600 SYMPTOM: On Playback of DCC tapes the Audio drops out. CURE: Set up as per the Service Manual the CASS motor speed (3264) MODEL: DCC600 SYMPTOM: No recording, play back O.K. CURE: Check digital PCB. Codenr. 4822 214 33899 MODEL: DCC600 SYMPTOM: Stops playing DCC tapes after a few seconds. CURE: Check whether connector 1327 is mounted well. MODEL: DCC600 SYMPTOM: Totally inoperative after some time. CURE: Check transistor T7349. MODEL: DCC600 SYMPTOM: The digital sound is sometimes interrupted. CURE: Replacing the digital printed board will solve the problem. The service codenumber of this board reads: 4822 214 33899. REMARKS : All sets from production week 9323 onwards have been modified. MODEL: DCC600 SYMPTOM: First 200 msec. no sound after next and prevous. CURE: Replace main processor to software version V72. MODEL: DCC600 SYMPTOM: Sometimes no sound on right speaker. CURE: Check Dig.PCB 4822 214 33899. MODEL: DCC600 SYMPTOM: Sound distorsion by interfering of a TV set. CURE: When the set is placed in the neighbourhood of a TV set (K40 type) the sound from the DCC is distorted. The distortion disappears as soon as the TV set is switched-off. As all DCC recorder complies the Philips requirements concerning magnetic fields it is advised to rearrange the set-up. It is known that some strong fields will interfere with the head connections. For this reason in the IFU is published: Do not place the DCC...near magnetic fields ... , ..) Placing the DCC at the other side of the TV-set (away from the high voltage transformer) can solve the problem. Adding an additional metal screen is also possible but is not a 'nice' solution in a home set-up. MODEL: DCC600 SYMPTOM: After about 5 minutes, set stops playing and relay starts clicking. CURE: Check IC7711 (PLC) 4822 209 31993. MODEL: DCC600 SYMPTOM: After some time noisy sound. CURE: Check digital PCB. It might be that ADC (AK5326) is heat sensitive. Replace digital PCB. (4822 214 33899) MODEL: DCC600 SYMPTOM: Sometimes middle and right-hand segments of display are failing. CURE: Check solder joints of the front processor and the FTD. MODEL: DCC600 SYMPTOM: Distortion of TV signal when DCC is in Play mode. CURE: Add screening (item 568) between DCC loader part and transformer/supply part. MODEL: DCC600 SYMPTOM: In some cases DCC cleaning cassette SBC3500 does not work properly. CURE: This problem is caused by a too long capstan (marginal difference compared with DCC900) which carries the cleaning cassette from the inside. In this case the DCC sensor switches are not activated and cassette is not accepted. Either fix a piece of adhesive tape at the bottom side of the cassette housing or drill a hole of 4.5 mm through the housing. REMARKS : Existing stock of Philips Service Warehouse is being reworked by drilling the hole. New stock will arrive with a thinner housing at the position the capstan is touching the housing. MODEL: DCC600 SYMPTOM: The player is reading and winding continuously. CURE: Check digital PCB (4822 214 33899) MODEL: DCC600 SYMPTOM: Too much wow and flutter on side A. CURE: Check pressure roller side A. MODEL: DCC600 SYMPTOM: After some time maximum error rate. CURE: Check digital PCB (DDSP IC7506 temperature sensitive ?). Service codenumber digital PCB is 4822 214 33899. MODEL: DCC600 SYMPTOM: Noisy and weak sound on the left channel with ACC. DCC OK. CURE: Tape drive unit defective. Replace tape drive unit. MODEL: DCC600 SYMPTOM: Does not play DCC cassettes. Max. error rate after cleaning head CURE: Replace the tape drive unit. MODEL: DCC600 SYMPTOM: Scratching sound audible when switching on. CURE: Check motor holder pos. 120 (4822 256 92024). MODEL: DCC600 SYMPTOM: Display inoperative. No light in the display. CURE: No -30V. Check safety resistor R3203. MODEL: DCC600 SYMPTOM: Transistor 7355 (BC817/40) in solenoid control circuit defective. CURE: Replace defective transistor by a new one (4822 130 42615). Check soldering of diode 6308 (BAS16) and the functioning of transistor 7205 (BD434) on main board. Check also the cooling of transistor 7205 on main board. REMARKS : Insufficient pressure of transistor clips will cause an increasing supply voltage of the play magnet (voltage on solenoid > 15V), which can destroy transistor 7355. MODEL: DCC600 SYMPTOM: Audio recorded on digital tape, no time or track nr. recorded. CURE: By replacing the tape deck mechanism it was found that this was actually causing the fault. Codenr. 4822 691 20833. MODEL: DCC600 SYMPTOM: Sometimes the use-again marker not found on customer recorded DCC. CURE: (Endless loops during append) Cut off minus lead of Electrolytic Capacitor 2711 on read/write board. Solder wire from minus lead of 2711 to pin 11 of IC 7703 (Read amplifier TDA1317). REMARKS : This phenomenon occurs only on Printed Circuit Boards with production stage .4 and is caused by crosstalk from WDATA to INAUX signal line. MODEL: DCC600 SYMPTOM: Set comes in a hang-up situation. CURE: The reset circuit has been improved to prevent hang-up, by changing item 3419 (refer to service manual page 48, mapping code M12) from 47k into 4k7 (4822 051 20472). (From productionweek 9316 onwards.) MODEL: DCC600 SYMPTOM: At first time cassette plays normally, second time set stops. CURE: Second time set stops in the middle of cassette. Resolder resistor 3263. Maybe this chip resistor 3263 was not good soldered and sometimes it does not make contact. This results in failing of the capstan motor. CAUSE : Temporally this resistor was hand mounted. From week 9312 onwards this mounting process has been changed. MODEL: DCC600 SYMPTOM: Noisy tray, squeaking sound during open/close CURE: Grease guiding parts of drawer pos. 209 resp. catch lever assembly pos. 216. with Molykote, service code 4822 390 20139. MODEL: DCC600 SYMPTOM: Poor loading function CURE: Slider opener (pos. 216-219 of Exploded View) lands on top of cassette. REASON: Shutter (pos. 552) out of form. Left side touches either bracket (pos. 551) or controlling lever (pos. 556). SOLUTION: Bend left side of shutter so, that there is no contact to other parts (min. distance between pos. 551 and pos. 552>= 0,1mm). REMARKS: Loading assemblies, marked with a red cross on the top of bracket 551, are already checked by the factory. MODEL: DCC600 SYMPTOM: Cassette gets stuck behind the front when lifted at left side CURE: This occurs when cassette is lifted at left side in order to remove it from the opened tray. The switch is opened/closed by a ridge, located at the back righthand corner of the drawer. To delay the switch actuation cut off some plastic of the ridge. Attention: This modification also takes an influence on the feature touch to close. If too much plastic is removed the tray might already close while a cassette is inserted ! Try to find an optimal compromise. CAUSE: The drawer (pos. 209) does not open far enough, because the tray-out switch (pos. 1437) is actuated too early. REMARKS: This publication will be followed by a service information. MODEL: DCC600 SYMPTOM: When using an ACC (analogue cassette) the drawer does not open. CURE: Plastic edge inside loading causes an analog cassette to get stuck. Remove the plastic edge. MODEL: DCC600 SYMPTOM: Drawer does not open. CURE: Check pos.212 (4822 403 70851) MODEL: DCC600 SYMPTOM: Gives DCC with CC cassette. Sometimes cass.blocked. CURE: Slide opener lands on top of cassette. Check position of the mounting tape foot. MODEL: DCC600 SYMPTOM: Updating uPs CURE: Updating uPs During the course of production the uP's in 70DCC300, 70DCC380 and 70DCC600 have been modified. Sets produced between week 9302 and week 9331 have old versions. In case one of the two uP's has to be exchanged in those sets, the other uP has to be replaced too, because in spare parts warehouse only the last versions are taken on stock. From week 9331 onwards front uP (item 7410) reads TMP870M70AF-6123 MASK V67 (available with service code 4822 209 32528). Main uP (item 7335) reads P83C528FBP/054 MASK V69 (available with 4822 209 32974). REMARKS: This publication will be followed by service information a93-362 MODEL: DCC600 SYMPTOM: Service Manual correction Electrical partslist CURE: Service Manual correction Electrical partslist digital board Codenumber for A/D-converter AK5339 (pos. 7514) was 4822 209 31622, should read 4822 209 33849. MODEL: DCC600 SYMPTOM: Guidance form CURE: Guidance form - Next Guidance form is enclosed at repairable unit 4822 691 20833. Please notice the wiring which should be included with the returned unit. GUIDANCE FORM REPAIRABLE UNIT 4822 691 20833 Please fill in this form and return it with the defective unit. TYPENUMBER (Unit demounted from set) : Serial number: COMPLAINT DESCRIPTION: INFORMATION GATHERED VIA SERVICE MODE EXTENDED PLAYMODE (selected via PLAY) WITH ERROR INDICATION (On display): MORE DETAILED OBSERVATIONS : YES NO TRAY LOADING OK DCC SOUND OK ANALOGUE SOUND OK MECHANICAL NOISE OK SPEED OK FRICTIONS OK TAPE TRANSPORT OK Return the defective unit complete assembled according to the drawing on the backside of this paper to: Invoice to: Philips Consumer Electronics B.V. 670005 Consumer Service - Price centre 5600 MD Eindhoven building SBP5 The Netherlands Ship to: Philips Consumer Electronics B.V. 676723 Consumer Service 5600 MD Eindhoven building SDM5 The Netherlands ATT: Mr. C. Lieberwirth CORRECTIVE ACTION/SOLUTION (to be filled in at central repair workshop): Report number: MODEL: DCC600 SYMPTOM: Customer problems when using DCC CURE: Customer problems when using DCC In general playing back pre-recorded DCC-cassettes does not bring problems to users, because playback of such a cassette is more or less simular to operating a CD-player. A number of problems are found in the playing back and/or recording of the user-recorded DCC-cassettes, caused by not proper 'initializing' of ALL these cassettes. Initializing is important because this is closely linked to basic customer-expectations of a digital product: - Track number; - Time indication. The DCC-standard distinguishes 2 different formats of user-recorded DCC-tapes: a. Super-user format b. User format But there are also combinations of the 2 user-recorded formats possible: c. Combinations of the 2 formats. And there is the pre-recorded DCC tape format: d. Pre-recorded DCC SUMMARIZED CHARACTERISTICS: a. Super-user format: - continuous absolute time information available (remaining time is calculated by the set) - Track numbering and track title at start of track are possible. (this means that also renumber is possible) - Initialization required - TOC (Table of Contents) possible at start of track 1 For figures see Audio Service newsletter 63.01 On Display when super-user format is loaded at position a: TRACKTIME - -10:51 b. User format: - No continuous absolute time information available on tape - No track numbering/title. (this means that renumber is not possible) - No initialization required The start markers are only used for track access. On Display when user format is loaded at position b: TRACKTIME : Notice: track is blank! Some DCC typenumbers show counter settings, others the estimated time based on the tacho-signals. c. Combination of the 2 formats. - This format usually happens when the APPEND function is not used. - The APPEND function is designed to guarantee the Super-user format in case a recording is made at the end of a partially recorded tape. When a recording is started on a blank area, the result will always be a User-format. Correction by renumbering is not possible. d. Pre-recorded DCC - Continuous time information available (inclusive absolute time, track time, remaining time etc.) - Track information continuous available - TOC information continuous available - Track title information continuous available. - Display will show on what ever position loaded the track and time information. example: TRACKTIME 210:51 MODEL: DCC600 SYMPTOM: Initialising DCC CURE: Initialising DCC NEW DCC CASSETTE: How to initialize the cassette (= making a lead-in recording at the beginning of the tape) is stated in the Instructions for Use. In the various typenumbers the following keys have to be activated: For DCC091, DCC450: REWIND, APPEND For DCC170: REWIND, REC PAUSE For DCC300, DCC380: REWIND, APPEND For DCC600: REWIND, APPEND For DCC730, DCC951: REWIND, REC SELECT/PAUSE For DCC900: REWIND, APPEND For more details: see Instructions for Use of concerned typenumber; chapter recording. After this initialization the track number and (absolute) time information will be recorded on the user-recorded tape. The above shown survey is a simplified universal applyable operation. The most problems are caused by the fact that users are accustomed to apply the record function straight forward, like recording ACC-cassettes. PARTIALLY RECORDED For all typenumbers, except DCC170: Use APPEND to search for end of last recording in case of partially recorded DCC-tape and so proper coupling of old and new recordings is made. For DCC170: Search Manually for END indication of last recording and make new recordings from that spot onwards. OVERWRITING In case of completely overwriting a user-recorded DCC-tape the initializing procedure has to be performed again! CONCLUSION: It is very important to initialize a user-recorded DCC-tape. If a DCC-tape is initialized or not, can easily be seen on the display information in Play-back mode. Starting at the beginning of the tape track time An empty DCC tape:: Not initialized DCC tape (User format) 11 : 24 Initialized DCC tape (Super-user format)312 : 49 MODEL: DCC600 SYMPTOM: Adjustment head current CURE: Adjustment head current - In case the read/write head of the DCC mechancism should be exchanged and/or the read/write IC's are defective the head current has to be re-adjusted. Because at this moment the needed test equipment is not available, this will be done in a central repair procedure. The following codenumbers are resorted in this repair procedure, at Philips Consumer Service known with code (REPARI 1 and 4): For 70DCC900: The complete tape deck mechanism item service codenumber 001M 4822 691 20777 For 70DCC300, 70DCC380 and 70DCC600: The complete loading mechanism item service codenumber LDU4822 691 20833 and The complete digital board (PCB5) item service codenumber 4822 214 33899 In case of a repair one has to ship, without waiting, the defective item to: Invoice to: Philips Consumer Electronics B.V. 670005 Consumer Service - Price centre 5600 MD Eindhoven building SBP5 The Netherlands Ship to: Philips Consumer Electronics B.V. 676723 Consumer Service 5600 MD Eindhoven building SDM5 The Netherlands ATT: Mr. C. Lieberwirth Please enclose a copy of the invoice inside the carton. The rest of the instructions are according to the PCS repair procedure available at the desk of Mr. Lieberwirth, Repair Manager, Phone +31-40-735509, Fax +31-40-734515 MODEL: DCC600 SYMPTOM: Trackselection CURE: Trackselection Direct track access is meant to search a wanted tracknumber by taking the shortest path to get to the track. Due to the differences in possible tapes, this topic is rather complex: * On a pre-recorded DCC tape, the Table Of Contents is always recorded continuously on the tape. This means that direct track access is possible. When jumping from track 3 to track 8. In this case the side is changed (from A to B) This is the SHORT SEARCH. * On a user-recorded tape, the Table Of Contents (TOC) cannot be recorded continuously. The TOC has be adapted all over the tape as soon as the recording on the tape is changed. For this reason the TOC can only be written at the start of track 1. This means that now jumping from track 3 to 8 results in so called SEQUENCIAL TRACK SEARCH. Jumping from track 3 to track 8 is done via track 4, 5, 6, and 7. In practise it has become clear that when a DCC is loaded, it is in many cases not positioned at the start of track 1. This means that the only alternative is sequential track search: The deck will in some cases not take the shortest path as the location of the required track is unknown. IMPLEMENTATION: DCC900 Writing TOC on user-recorded DCC was planned but did not fit into the microprocessor internal ROM capacity. To delete this possibility from the specification was a last minute decision. Unfortunately the Instruction For Use has not been adapted accordingly. That is why 10-key commands are not accepted (NO TOC message). There is no service solution available. DCC600 Writing TOC on user-recorded tape was also not possible because of the limitations of the microprocessor internal ROM capacity. Lessons are taken from DCC900, that is why the sequential search possibility has been implemented. When a 10-key command is issued and the TOC is not known, the deck will perform this above described sequential search. The result is that DCC600 will in only a few cases not respond to a 10-key command. Due to the fact that the microprocessor of the DCC900 is completely filled and no larger memory is available, a service solution which incorporates sequential search like DCC600 is not possible. MODEL: DCC600 SYMPTOM: Modification speed control CURE: Modification speed control In the course of production the temperature stability circuit of the speed control has been improved. This may influence the compatibility of the LDU1000 loading assy (4822 691 20833). This loading has to match with the various versions of the main pcb because components on PCB3 (main pcb) and PCB6 (dcc-indicator) have been changed. Situation Loading marked LDU1000 WT00 and WT01: PCB3: R3262 (12k) with parallel to it potentiometer 3264 (10k). In series with this 3263 (12k). PCB6: NTC-resistor 3160 (150R) in series with capstan motor. Situation Loading marked LDU1000 WT02: PCB3: R3262 (deleted), potentiometer 3264 (4k7). In series with this potentiometer 3263 (15k). PCB6: Resistor 3160 (100k) in series with diode 6601 (kathode at 3263 and - (MINUS) capstan motor, anode at 3160) parallel to capstan motor. Therefore: In case the loading assy with with printed board PCB6 has to be replaced the built-in main pcb has to be matched to the production stage of the LDU1000 delivered. Replacement procedure: 1)When replacing a Loading marked LDU1000 WT00 or WT01 by a WT02 version, R3263 has to be changed from 12k to 15k! When replacing a Loading marked LDU1000 WT02 by a WT00 or WT01 version, R3263 has to be changed from 15k to 12k! 2)Adjust speed control as described on page 28 of service manual. 3)Check Tape up torque, wow and flutter (for limits see page 28 of Service Manual). 4)Check Analog feedback level and bias. (read/write pcb) 5)Check Dolby level if necessary (main pcb) MODEL: DCC600 SYMPTOM: Codenumber information CURE: Codenumber information DCC Cleaning cassette SBC3500 is from now on available with service codenumber 4822 015 20646. MODEL: DCC600 SYMPTOM: Availability of front boards CURE: Availability of front boards Front boards for DCC-recorders with mounted uP are available now: 70DCC300 : 4822 214 52176 front board 70DCC380 : 4822 214 52177 front board 70DCC600 : 4822 214 52178 front board MODEL: DCC600 SYMPTOM: Correction partslist RED1 Tape Transport CURE: Correction partslist RED1 Tape Transport Capstan motor item 1023 was 4822 361 21506 should read 4822 361 21646. 4822 361 21506 is capstan motor of REN and RER tape decks. MODEL: DCC600 SYMPTOM: Corrections to the service manual CURE: Corrections to the service manual - The service test program (page 25-26) Key test : Correct key to enter this test is 'MARK WRITE' Hole test: This test can only be entered if tray is in opened position. In tray test the tray is moved outside. So first start with tray test before hole test. IR test: RC-5 codes of TEXT and TIME have been exchanged in this publication. RC-5 code for TIME should read '11', RC-5 code for TEXT should read '122'. Adjustment table (page 28) Position number of potentiometer for take-up torque should read 3280. REMARKS: This publication will be followed by service information A93-362 MODEL: DCC600 SYMPTOM: Modification CURE: Modification In course of production the power supply circuitry of the read/write board has been changed: * Double-diode pos. 6703 (BAV99 - 5322 130 34337) has been built-in in series to the voltage stabilizers 7701 and 7702. The double-diode reduces the input voltage of the stabilizers and thus the power dissipation of these ICs. * Voltage stabilizer pos. 7708 has been changed to a type with low voltage drop (LM2931Z-5.0 - 5322 209 60749), capacitor pos. 2764 is changed from 10nF to 10æF (4822 124 23179). Both actions improve the plop-behaviour when the set is powered-off during a recording session from an analog source. REMARKS: Modifications have been taken place in read/write boards from production stage .5 onwards. Production stage can be identified by the last digit of the twelve-figure number, located at the lower right corner of the printed circuit board. Reel to reel Teac mixers 5a !!! model3 Model 3 8-In, 4-out 2 Monitor (8x4x2) portable mixer. 1983...M-30 M-35　(8x4x2)an 8-in, 4-out, 8 monitor M-35EX expansion to 28 inputs. M-50 12 input, 8-buss　2 aux M106 (6x4x4) M208 !! (1985 8x4x2) M216 (16x4x4) M308 (8x4x8) Simul rec capture card -> recorder options -> max recordings : 3 is a sensible setting Teac A-3440 As an A-3440 enthusiast, I'm glad to hear you were able to get the issue resolved, thanks to Sam, he's the man! I'm just curious if you can check the serial # on the back of yours, which indicates the manufacturing date (the digits on the right side of the s/n). I believe the A-3440 was introduced in '78 (not sure if was the beginning of the year, or more toward later), along with its matching 2A mixer. (My older brother bought one new back in '79, when I was a teenager). The Tascam 34 came out in '82-'83, but I find it interesting that the A-3440 didnt seem to be discontinued, and was still being made at the same time as the 34. Does anyone recall what the $ price difference between them was?, just curious. I have a collection of Teac/Tascam literature, and it appears that the A-3440 and 2A were still around as late as 1984. Anyone know if the 40-4 made it that far as well? I was also curious if there were any revisions made to the A-3440 during its production run. Is an '83 A-3440 exactly identical to a '78 model, or are any circuit boards and components, etc different? I know the Model 2 (2A) mixer had a few slight changes- the knob colors and fader controls, and also had the raised meter bridge with faux-wood panels... Just a few lil' details I find interesting, if anyone else might also relate. Tapetech,Yes .the two micro swt's that the tension arm makes contact with.The one that engages the pinch roller was bad.Teac p/n is 51300010. Hi BeatleFred, The items in the A3440 that need attention are pots, capstan motor and belt as well as the Pinch Roller Linkage for grease issues. I have had a few electronics failures in the past but I would say that the electronic failures will come more often due to caps than in the past. The changing of a lot of Electrolytic caps by a good technician can not be that hard as the cards pull out the bottom and can very easily be done on the bench. Much easier than an X1000R or A3340S. They should be changed as they are going to be drying up. After 30 years of sitting and power being applied scarcely they can not be that long lasting plus this is not a large investment in parts. Who knows, in 2 or 3 years the current Electrolytic capacitor might be all gone due to lack of manufacturing and then everyone will be scurrying around trying to find some and end up with the Chinese caps that won't be a plus to use. Nobody sees this better than I on the front line. Get them done, date the board as to when and move on using a well operating machine. The RX-9 is a unit that could have problems due to the high use of relays. The real solution is to use the better DX-4D unit as they do both jobs all the time- the is 4 encoders and 4 decoders all the time. The control cable is not needed in that case as it was for encode and decode switching depending on mode. They (RX-9) are going to be costly to repair as well. The dBx units are used for NOISE REDUCTION and nothing else. They do not make the music more dynamic and if they do that is because the deck is out of calibration and is showing a double error in the record process. When you use two track you can get away with no noise reduction, when you strat mixing the noise adds up. When you get to 8 tracks you for sure need it. With 4 tracks that can be a matter of opinion and a part of the recording process. I used it in many demos I did and it worked well all the time- then again my machines were well calibrated at the time unlike some peoples' decks that can be far off and the dBx just makes it worse. The FV cable and circuit in the DX-4D can be removed and circuit disabled- I have done a few and there is no need for that cable anymore. The DX-4D can then work just fine as long as the proper nominal levels are put into it. Output levels and mixer settings. The reason a mixer or tape deck is set at what is called specified output level is that this is a setting which is giving a known output at approximately a 70% gain setting. Most mixers have a grey area on the panel at 70% area. This is put there not to make it pretty but to give indication that this is the unity gain setting of that circuit. The Unity gain setting is one where neither gain or attenuation is used for the signal. Gain adds noise as the signal is too low, attenuation is needed because the signal is too high. Due to power supply rails, it is best to stay inside of the good operating position of the power supply rather than having the decks output at max (again a gain setting) and to allow the deck to put out a sufficient signal without hitting the clipping point or that of exceeding the power supply rails that an Op Amp can handle. In studios I always set my machines up for the specified output position and then leave it there. Tape pack is one thing that the newer better machines do best. They should all be this way but over time the tape deck makers did not start all of their decks out with the most latest technology. The decks like the Tascam 52 can wind tape with little scatter. The spooling mode packs the tape as if it was just played. The Tascam 42 does the same thing but looses some control over the tape due to the arm configurations. That is why the Omega drive was made and included in the 50 and 60 series decks. All you can do on a A3440 is to use good back coated tape and to make sure the reels you use and TZ612 are in good shape and to try and not get the reel tables damaged. The tension arms need to be kept clean and edges to a minimum and polished. It can make a world of difference like when JRF gets done polishing a head stack, there is no tape handling problem when he is done and the overall performance is enhanced due to it. This does not make the tape pack different but it travels across the heads much better. Oh, the electrolytic caps should be changed prior to calibration as the better caps will make gain changes. I don't know of anyone who is willingly using 60 year old Electrolytic capacitors in their circuits. I hope this addressed all the questions you had. --- My older brother bought a 3440 new back in 1979 when I was a teenager and I remember being quite impressed with it. I have two of them, one that I bought in '94 and another that I acquired on Ebay about five years ago. I also have several Model 2A mixing boards (the 2 and 2A being the matching mixer to the A-3440, and its even better if they come with the MB-20 meter bridge). The RX-9 was the matching noise reduction unit that fits directly underneath the recorder if you remove its feet. The Ebay seller had done most of the maintenance on it, but I havent had the free time to use the recorder in a long while, so I'm hoping when I start using it again soon that I wont have to confront any major issues from it being inactive so long, other than replacing the belt which most likely will need to be done. I always thought the A-3440 was a great unit, I just love the way it looks and sounds. I have all the literature on it- brochures, manuals etc. I find it interesting that even though Tascam introduced the 34 in the early 80's, the 3440 was still in production and not discontinued. I have a Teac catalog from '84-'85, and the A-3440/2A are still shown. By the way, you can find the manufacturing date of your recorder from the serial # in the back. There is a sequence of digits and then a two digit # - for example, an 03 would mean the 3rd quarter of 198>0. (1980). A great magazine was 'Modern Recording'- I'm glad I saved all the issues I bought back in the day along with what my brother had when he subsribed- alot of good info in there on various Teac/Tascam equipment. I think the A-3440 is geared more toward home recording/multitracking, rather than as a straighforward recorder like an X-2000/1000 etc... But if anyone desires one, the A-3440 is not that difficult to find on Ebay, people are still buying them for a reasonable price. http://www.youtube.com/results?search_query=teac+a-3440 Tascam history 1979 (cont.)... TEAC introduced the A3440 1/4 inch multitrack, an upgraded 4- track open reel recorder. Even thought the A3440S had the TEAC brand name, it was sold by the TASCAM sales organization through music stores. 1983...TASCAM introduced the 30 series recorders. The TASCAM 38 was a 1/2", 8-track, 10 1/2" reel-to-reel recorder. Introductory price was under $3,000. The 38 filled a niche for the serious entry level recordist. The TASCAM 34 was a 4 track recorder with full frequency response in Sync Mode at an inexpensive price. The TASCAM 32 was a half track master recorder/reproducer using 1/4" tape. 1986- Tascam 34B 1991- The TASCAM 1500 Series were 4-buss recording consoles with 8 directly assignable outputs. The M1500 series included an 8-input version, the M1508, and a 16-input version, the M1516. ===== Full history: Teac/Tascam models list rom our ads and catalog collection 1960 - Teac 505 1961 - Concertone 505 1966 - A-610, A-5050, A-4010S, A-3010, A-1200, A-4020, A-2020, A-1600, A-1500,R-310 1967 - R-1000, R-1100, A-4010, A-4020, A-2020 1968 - A-4010S, AS-200, A-6010, A-1200 1969 - R-310, A-1200U, A-6010, A-4010S, A-4010 SRA Quad 1970 - A-100, A-1200, A-1500, A-1500U, A-6010, A6010U, A-7030, TCA-40, TCA-41, TCA-42 1971 - A-1200U, A-1500, A-6010U, A-7010U, A-7030U, A-3300, 4010SL, 6010SL, 7010SL, 7030SL, 3300-10, 3300-11, 3300-12, 1230, 1250, 4070, A-1200, TCA-40, TCA-41, TCA-42, An-180, AN-80, An-50 1972 - 2340, 3340, TCA-43 (1st Simul-Sync), A-4010GSL, 6010SL, AX-300, AN-300, A-6100, An-180, AN-80, Tascam Series 70, Tascam Model 10 mixer 1973 - 1230, 1250, 4010GSL, 6010GSL, 7010GSL, 7030GSL, 4070GSL, 3300-10, 3300-11, 3300-12, 2340, 3340S, TCA-43, AX-300, AN-300, Tascam Series 70, Tascam Model 10 mixer 1974 - TASCAM acquired by Teac, Tascam Series 70, Tascam Model 10 mixer, Model 5 mixer, Teac 2340, 3340S 1975 - A-2300 SX, A-2300SD, A-3300SX, A-3300SX 2T, A4100, A-4300SX, A-6300, A-7300, A-7300 2T, A-3340S, A-2340SX, Model 2 mixer with MB20 meter bridge, AX-20 mix down box 1976 - Tascam 80-8 (used for Star Wars R2D2 sound), Model 1, Model 10B, Teac A-7300RX, A-3300 2T,A-2340, A-3340, Model 3 mixer, Model 5 mixer, Series 80, 40-4 1977 - Tascam DX-8, Model 25-2, Tascam 80-8 (Star Wars released), 25-2, A-2300SX, A-2300SR, A-2300SD, A-3300SX, A-3300SR A-3300SX 2T, A-4300SX, A-6300, A-6600, A-7300, A-7300 2T,A-3340S, A-2340SX, Model 2 mixer with MB20 meter bridge, Model 5 & Model 5EX, Studio 4000, 40-4, Model 3 mixer 1978 - Model 2 mixer, model 15 mixer, Tascam 80-8 (used for Star Wars R2D2 sound ads), Model 5A mixer, 25-2, Studio 8000, A-2300SD, A-3300SX 2T, A-4300SX, A-3300S, A-2300S, A-3340S, A-2340S, A-7300, A-6300, A-6100 1979 - Tascam 90-16, Teac 3440 , Model 144 Portastudio, 80-8, 40-4, 35-2, 5B & 5BX, Model1, 1980 - Tasccam 85-16, A- 3440 , A-3300SX 2T, A-2340SX, Model 2, MB20, A-6100MKII, GE-20 eq, 80-8, X-3, X-10R, ATR-700 built for Ampex, 1981 - Tascam 80-16, System 20, Model 15SL mixer, 80-8, 40-4, Model 1 mixer, System 20, 22-2, 22-4, ATR-700 built for Ampex 1982 - Tascam Model 15 SL, 80-8, Model 16 mixer, 85-16B, M-30, M-35 mixer, 32, 34, 38, 22-2, 22-4, Teac X-10, X-10R, X-20R, System 20, A-3440 , X-1000R, ATR-700 and ATR-800 built for Ampex 1983 - Tascam 38, Tascam 58, , ATR-700 and ATR-800 built for Ampex, 22-2, 22-4, Series 50 52, 58, 80-16B, System 20, M50 mixer, M-15B mixer, M-16 mixer, Series 30 - M-30, M-35, 34, 38 1984 - Teac X-300, X-300R, X-700R, X-2000, X-2000R BL 1985 - Tascam 388, MS-16, Teac X-300, X-300R, X-700R, X-2000, X-2000R 1986 - Tascam 388, 32, 34B , 38, Series 40, 42B, 44, Teac X-300, X-300R, X-700R, X-2000, X-2000R 1987 - Tascam 388, MS-16, ATR-60, ATR-80/24, Teac X-300 , X-300R, X-700R, X-2000, X-2000R 1988 - Tascam Digital 24 track, 22-2, 32, 42B, M-600 mixer, ATR-60, ATR-60T, ATR-60-8, ATR-60-2N, ATR-60-2HS, ATR-60-16, Teac X-2000M(RO), X-2000(RO), X-2000R, X-300, X-300R 1989 - Tascam MSR/24, MSR-16 1990 - Tascam MSR/24, MSR-16 1991 - Tascam M3000 mixer, MSR/24, MSR-16 1992 - Tascam BR-20, BR-20T Reel to reel tapes info When reel-to-reel tape was still a studio/consumer product, BASF followed a naming convention that defined the product type. In 1984 it became clear that open reel tape was only going to be a professional product in the future, and the naming convention changed with the introduction of "SM 910"--Studio Master 910. The US market named the consumer products differently, and that accounts for addition confusion. The general run down of products and naming conventions follows. The product type was first defined by a two-letter designation describing the playing length, followed by a number defining the total thickness of the tape in microns. If the tape were back-coated, an "R" for "rueckseite" followed the playing length. The final letters, if they appeared, described the type of coating. SP 50 = standard play for 50-micron tape with 1.5 mil base film; 1200' reels LP 35 = long play for 35-micron tape with 1.0 mil base film; 3600'/1800' reels DP 26 = double play for 26-micron tape with 0.75 mil base film; 2400' 7" reels TP 18 = triple play for 18-micron C-60 cassette tape; 15,000' pancakes QP 12 = quadruple play for 12-micron C-90 cassette tape; 23,700' pancakes XP 9 = extreme play for 9-micron C-120 cassette tape; 10,800' pancakes "LH" stood for "low noise, high output" oxide used for better than average performance. "LHL" was a formulation for low printthrough, and "LHS" was an advanced oxide with slightly higher coercivity intended for consumer use at slower 3.75/7.5 ips recordings rather than the more common 15 ips speeds used in the studios. So the SPR50 LHL from the late 1970s was a 1.5 mil backcoated studio tape with lower printthrough than normal. For the US, the names differed a bit: Performance = 3600'/1800' reels of LP35 standard oxide Studio = 3600'/1800' reels of LP35 LHS for slower consumer speeds Professional = 3600'/1800' of backcoated LPR35 LH for professional use In the mid 1980s, it was "clear" to the marketing departments that open-reel was dead as a consumer product. In the US, the product managers tossed out scores of unopened boxes of open reel tape into a dumpster. I climbed in and rescued them all for preservation and my own use. The professional group continued to sell the product, of course, and the naming conventions changed to distinguish the use of the product. LM 920 Loop Master chrome tape in 1- and half-inch width for loop bins LM 921 Loop Master bin tape with an improved formulation SM 910 Studio Master tape in widths from quarter inch to 2 inch; 50 microns SM 911 Studio Master tape with reduced modulation noise that replaced 910 SM 468 Studio Master tape inherited from Agfa; very high coercivity SM 900 Studio Master tape to compete with Ampex 499 and 3M 996 LPR 35 a throw back to the old naming convention for 1 mil tape It should be noted that BASF, unlike Agfa, Ampex, and 3M, never used the polyurethane infamous for breaking down over time and causing sticky tapes. I've used a lot of open reel tape over the years, and there is no other tape that outperforms BASF mechanically. Maxell made a great open reel tape; but in published, independent comparison tests for electro-acoustic properties of consumer open reel tapes, BASF was the regular winner. All of the tapes I salvaged years ago still wind perfectly with no significant rub off and no sign of shedding. The story I heard was that our chemical group refused to use the questionable polyurethane binder, not because of environmental concerns about longevity, but because Agfa-Gevaert held a license for it. They refused to pay Agfa for anything. That's why PEM 469 and 469 had shedding problems and SM 468 and SM 911 / LPR 35 LH(S) did not. If you're not having a problem with the sample you have and all of the others come from the same lot, then you may have product that Agfa produced with a different binder. They caught on quickly to the breakdown and were one of the first to promote the heat treatment for temporary salvage. I'd keep the tape and watch it closely for awhile. If no problems show up, you've got a great tape. After we bought Agfa, I wanted to stay with PEM 469 because it was already in use in some studios. The problem was that Agfa had a very small market share compared to Ampex and 3M, and PEM 469 had a reputation sullied by the binder breakdown. We decided to bring in SM 911 and 900 instead and price it slightly below Ampex and 3M. That was the biggest mistake of my career at BASF. No one was interested. Fortunately, no one noticed either. So I changed my mind and raise the price 15% above Ampex and 3M. That's when the studios got curious. (A "cheap" European tape is not interesting; but an expensive Porsche/Mercedes/BMW/Audio image is intriguing--especially when the client, not the studio, pays for the tape.) That's when sales really began to increase. Once 3M dropped out, we had the future wide open--until BASF sold the tape division off and fired all the experienced people. cassette tape info A data sheet for a tape has almost all the explanations of tape differences. However, they are hard to understand because of all the curves. Tape experts can judge a tape's electro-acoustic performance from a data sheet and estimate what it will sound like on a machine calibrated for a different tape and know what adjustments need to be made in order to align a deck to the tape described on the data sheet. The only quality parameters not mentioned on a data sheet are mechanical ones: rub-off, adhesion to the base film, stiction, surface polish, and so forth. (If I ever get time, I'll finish the paper on how to read a data sheet.) 1) Frequency response curve--although data sheets are full of curves, those curves represent the effect that bias current has on the output of number of signals at different frequencies. None of the curves is flat. If the sheet shows that a sweep of 12.5 kHz is 6 dB below the output for 315 Hz at -20 dB below the reference level, then the record pre-emphasis must be boosted by 6 dB at 12.5 kHz in order for "flat" response. I have nver seen the type of frequency response curve familiar to consumers on a tape data sheet because that type of curve is reliant on the hardware. 2) MOL is a very important characteristic, but it is offset by noise. Metal tapes have very high MOL values, but they also have poor noise levels. Their signal-to-noise ratios are often little or no better than those for high performance Type II tapes with lower MOL values and lower noise. MOL is a function of magnetic pigment, coating thickness, loading values (ratio of pigment to binder), and uniformity of particles and alignment. The values given in remanence figures correspond to MOL. 3) SOL defines short wavelength output at the point where an increase in input level no longer produces any increase in output because the tape saturates, that is, the high signal level begins to erase the output. This point is hard to define, so greater precision is given when two tones having a frequency difference of 6% are recorded simultaneously and the intermodulation between the two reaches 26.6 dB. SOL values are largely dependent on coercivity. The harder it is to coerce or force a particle to switch its magnetic poles, the harder it is for the particle to self-erase. Type IV metal tapes have the highest coercivity and, therefore, the highest SOL values for cassette tapes. For open-reel tape, SOL is less critical because the higher tape speeds increase the room for wavelengths and dramatically reduce the effect of self-erasure. However, note that "consumer" tapes often show slightly higher values of coercivity because they are designed for acceptable performance at 3.75 and 7.5 ips rather than the studio speeds of 15 or 30 ips. 4) Noise--there are several different measures of noise. Bias noise (a function of particle uniformity and alignment), modulation noise (a function of uniformity of dispersion within a coating, particle uniformity, and surface smoothness), and DC noise (particle shape and distribution). These noises depend on the tape design and processing far more than on any hardware. Chromium dioxide tapes are the best for all of these types of noise because the particle is a "perfect" shape--a long, thin glass-like rod with no external deformities. The shape makes the pigment easy to disperse and align in a coating and gives chrome the low noise values it has. Metal particles, although extremely small and nicely shaped, are very difficult to align because of their enormous coercivity. Coercivity gives metal tape the highest SOL values and excellent MOL values, but those values are reduced by the very high noise levels. For standard oxides, lower noise is a function of the pigment processing to reduce deformities of the particles (often called "dendrites"--Greek for "tree" because the uniformities look like branches coming from a tree trunk) and of the milling process to isolate and evenly disperse the particles within the coating. Ions of cobalt can be added to some standard oxide particles to raise their coercivity at the risk of some instability unless processing steps are taken to reduce the risk of lost remanence from physical forces (the magnetostrictive effect). 5) Uniformity is critical for tape, but what you described is a function of physical stability within a cassette housing, which brings up all sorts of other issue. Tape uniformity can mean two things: A) no deviation from batch to batch; and B) no deviation from beginning to end or from width to width. BASF held very tight specifications for batches of tape so that sensitivity at 315 Hz, for example, did not vary more than +/- 0.5 dB and for 10 kHz more than +/- 1.0 dB for millions of kilometers of duplication tape. This was because duplicators did not want to have to realign equipment for every batch that was delivered for their music cassettes. The beginning of a 23,000-ft cassette pancake should have exactly the same values at the end of the pancake so that the first cassette from the roll should sound exactly like the last cassette. In studio production, it was even more critical because the sensitivity across a 2-inch width of tape should not vary at all because multiple tracks had to remain in balance. BASF used a knife coating method, and the knife was controlled by a computer that sensed output of the coating and automatically adjusted thickness for uniformity of output. The values of thickness could change slightly through a reel or pancake, but the sensitivity did not. (I believe that Ampex and 3M also used the knife method while the Japanese used gravure coating. Stories about Nakamichi selecting only "center cuts" from TDK production may indicate why BASF/Agfa, Ampex, and 3M produced 1-inch and 2-inch mastering tapes and not the Japanese. There was a very distinct difference between tapes not only in pigment but also in processing. Now that there are only a few producers making only a few types, the differences are fewer that they used to be. the end BASF AG tried to unload the tape division to RAKS, the Turkish company, in September, 1996; but there was a riot when German workers found out. The deal was called off. In October of the same year, BASF AG convinced Kohap, the Korean chemical company, that buying a magnetic tape company made good sense for vertical integration. The argument was that demand for VHS video tape would remain strong with continuing but slow growth until demand peaked in 2010--that's last year!--with a slow decline in subsequent years. The BASF management actually believed it and forced anyone with a different opinion to keep quiet. Kohap fell for it. Kohap arranged to keep the BASF logo for five years, with the "by EMTEC" qualification in place until such time that EMTEC would appear in the white rectangle in the logo. EMTEC was the subsidiary fully owned by Kohap, except in the United States where BASF management sold rights to distribute EMTEC products to Joseph Ryan (professional products, which was the only profitable division) and Sigmar Tullman (computer products). The reason for this odd approach was that the Department of Justice could not stop these "independent" distributors from their business if BASF were found guilty of price fixing for a third time. Kohap was not aware of this arrangement and was furious when they found out. In 1998 Kohap bought the professional and computer business back, but Mr. Ryan, who had named his company "JRPro Sales" after himself, had in six months brought the professional division to such losses that EMTEC could never recover. Korea fell into a severe recession a few years later, and Kohap was forced to sell off EMTEC to investment bankers. Once these bankers saw the books, they were appalled. It didn't take long for them to break the company apart and sell off whatever they could to anyone interested. Imation and Aurex bought some equipment and raw materials. Most of the rest went to scrap. BASF had an operation just across the German border in France where audio and video tapes were loaded into housings molded and assembled in the same plant. I don't know why these cassettes are labeled "Made in Korea" unless they are part of an arrangement with SKC. SKC, Aurex, and BASF were all engaged in price fixing bulk audio tape in 1994 and 1995, and there were meetings in Seoul, Korea even in early 1997. S.K. Moon from SKC attended the first meetings and was fired for refusing to attend any more. He sued SKC in the state of California, and that's when the U.S. Justice Department got wind of the arrangement. Two weeks after Moon sued SKC, BASF Magnetics announced the fire sale to Kohap and fired Terry O'Kelly, the only BASF director who refused to participate in any illegal meetings at all. Since Kohap had no tape production, loading, or packaging equipment at all in Korea, these cassettes are either from SKC or from Saehan, another supplier to BASF in those days. Even though there was a loading and packaging operation in France, if the cassettes say "Made in Korea," they would have to have come from either SKC or Saehan. The reason for the long story is that it had a lasting affect on tape production. In 1996 BASF Magnetics in the U.S. was expanding its professional division, and a number of Quantegy executives had asked O'Kelly if they could be part of that expansion. They all knew that VHS and audio cassettes had a limited life, but pro audio/video could be based on tape products if there were a reliable source. BASF had hired top sales people from Quantegy, Fuji, and Sony in the summer of 1996; and there was every reason to believe that BASF could easily become the largest and most stable tape supplier in the world. The threat of the price fixing lawsuit destroyed all that. BASF replaced O'Kelly with Ryan, the new sales people quit and sued BASF for "misrepresentation," and what was formerly the most profitable division began to bleed money. 3M had abandoned tape; Quantegy was struggling; and now BASF shot itself in the face. Recording studios watched all of this and decided that a move to digital was the safest bet. Analogue tape recording did not have to die off as quickly as it did. sticky shed syndrome The sticky-shed syndrome is a function of a breakdown in the polyurethane binder used for the magnetic coating due to hydrolysis--allowing water molecules to attach themselves to the magnetic pigment. The "baking" method merely drives the water molecules out of the coating for a temporary fix. Repeated bakings are less effective because the heat itself may stress the coating chemistry. The only association with backcoating that I am aware of is coincidence--the binder used was expensive and used almost entirely on premium tapes that were always backcoated. The problem is the oxide coating, not the backcoating. Calendering is a process of using rollers filled with either hot or cold water or oil--the choices varied depending on the type of coating--that squeeze the magnetic surface of the magnetic coating to flatten and polish it. Backcoating is applied after calendering because the surface of the backcoat must be rough enough to allow air to pass across its surface in order to provide smooth winds at high speeds. I don't know enough about molecular chemistry to offer any expert opinion about the effectiveness of using NuFinish to resolve the problem, but I do know that surface finishes were applied to some tapes after coating and calendering for specific applications. The composition of NuFinish is designed to add a quick-drying lubricant to the surface of paint and to use micro- or nano-particles to fill in scratches so that the paint surface looks smooth. Magnetic tape is little more than magnetic paint on plastic film. In fact, the first tapes were reddish brown because the ferric oxide used was very similar to that used in inexpensive paints. Barns are red or reddish-brown because the color pigment used in those paints is iron oxide--cheap, stable (it's already rusted!), and effective. Applying a paint finish to a magnetic tape is not that far off the mark. Those who have tried it claim that it allows tapes formerly cursed with the binder breakdown to not only run without sticking but to be able to reproduce themselves effectively, even after long periods of time. That would be significant. If that works predictably for every binder-failed tape that needs to be transferred to another medium, it would be a better solution than baking a tape. However, if the treated tape is to be kept as a master, then one must investigate some other considerations: 1) does the treatment work for all the various binders that have failed (Ampex, Agfa, 3M); 2) does the treatment last for all the various binders; 3) does the treatment lead to any other deterioration; 4) does the treatment have any effect on headwear; 5) does the treatment have an effect on gap life? Micro- and nano-particle technology have come a long way since tapes have been manufactured, as has polymer technology. It would not be a surprise to me that developments meant for auto paint finishes would also work for magnetic paint finishes. It's a pity BASF got out of tape so soon because they are also a very large auto paint supplier. The code works this way: SP50/52 = single play on 1.5-mil base film; total thickness from 48-50 microns LP35 = long play on 1.0-mil base film; total thickness from 35-36 microns DP26 = double play on .75-mil base film; total thickness 26-29 microns TP18 = triple play for cassette C-60 tape or super-thin open-reel QP12 = quadruple play for cassette C-90 tape XP9 = extended play for cassette C-120 tape For reels, the lengths are: 7-inch reel 10.5-inch reel 1200 feet 2400 feet SP50 1800 feet 3600 feet LP35 2400 feet DP26 3600 feet TP18 If there is an "R" after the length designation, the tape is backcoated. The next two or three digits designate the type of coating. "SPR50 LHL" was a studio tape on 1.5-mil film with a total coating thickness of 52 microns, including the backcoating. The oxide was Low noise, High output, with Low print levels. The gray cases or black cases were used for a number of different "domestic" or consumer open-reel products. SP52 was a "general purpose" tape with average performance. Although LP35 LH and LPR35 LH would seem to differ only in the backcoating, they used different manufacturing processes so that the former was an average tape while the backcoated version was a much higher performance tape suited for 7.5 or 15 ips recording. LHS tape had a higher coercivity designed for good performance at 3.75 or 7.5 ips recording speeds. Over the years oxides and processes changed more often than the names, so it is sometimes hard to equate performance with just a name. Although BASF did not suffer from binder breakdown, the standard LH formulation--called "Performance" in the U.S.--did have some slight granular rub-off of the oxide. LPR35 and LP35 LHS were as clean as a whistle--I have never found oxide on guides or heads when using those tapes. Ampex and SSS Unlike Ampex, who used polyurethane in their binder mix, when the SSS issue came to light in the early 1990s, in a meeting (organised by Ampex BTW) between the tape manufacturers and the ARP, BASF stated they only ever used polyethylene in their binder and their tests showed it did not suffer from hydrolysis. This tape may be suffering from other break down cased by poor storage. It’s likely to be heading for 40+ years old as it is. The boxes may look ok but if the RH of the storage area is too low or it’s subject to extremes of dry heat or cold, that could affect it. BTW Ampex made more 456 than any other tape from any other manufacturer by a long margin and for a long time. Over that period they bought binder in from a number of suppliers, 3M being one. The issue that causes SSS is hydrolysis. All PE binder suffers from this but the “string length” of the PE strands dictate how quickly this occurs. Test made on short string PE showed it could suffer from hydrolysis within 48 hours. But long stringed PE binder was inconsistent in its coating of the backing making the tape surface bumpy. Medium string was the compromise. But until Ampex installed gas spectroscopy equipment in their production plants in 1981 to check the consistency of string length, the previous binder mixes they used had a variable mixture of string lengths. Hence not all 456 suffers extreme SSS, but due to the late introduction of the GS inspection kit in the manufacturing lifespan of the product, the chance that Ampex products do suffer SSS is likely. Coupled to this is storage conditions: The ideal temp and RH, both or which, the tape manufacturers recognised that the users of their products were very unlikely to have in their tape stores. And you thought reel to reel was just a bit of rust moving over a bit of metal to make a sound! Reference Tapes - Calibration One further question. I have a 185nWb calibration tape. Can I use it for the PR99 or should I get a 250nWb? You can use a 185nWb/m reference tape by calculating the corresponding levels to use - on page6 of this publication, there is a explanation http://home.comcast.net/~mrltapes/choo&u.pdf Plakkende tapes afspelen Gevonden op het audiofreaks forum: Ik heb een goede manier bedacht om plakkende banden nog goed af te spelen. Bakken is mij nooit gelukt. Band twee keer heen en weer spoelen buiten koppen en bandgeleiding om, dus van reel naar reel rechtstreeks. Hierbij het afslagarmpje even vastzetten. Dit doe je door een doekje heen dat vochtig is gemaakt met IPA. Dat hou je om de tape heen, lichtjes aangedrukt met je vingers. Hou de tape in het midden om aanlopen te voorkomen. Spray nu 2 a 3 pufjes WD40 op hetzelfde doekje, en bevochtig het opnieuw met IPA. Spoel nu opnieuw de tape heen en terug door je vingers met het behandelde doekje. Nu kun je de band gewoon afspelen en direct kopiëren of digitaliseren. Banden die niet meer wilden spoelen (Scotch o, a.) kan ik nu normaal afspelen en zelfs weer opnemen. Het zeer dunne laagje WD40, je moet niet overdrijven, vormt een nieuw smerend laagje. Door het afspelen wordt het ook goed verdeeld. Normaal bevat een tape ook een smeermiddel, maar dat is kennelijk na 40 jaar uitgedroogd. Maak vooraf en achteraf steeds ook de koppen schoon om de originele prut te verwijderen. WD40 droogt uiteindelijk volledig in en integreert met het tape oppervlak. Het geeft in mijn ervaring niet af of zo. Experimenteer eerst eens met een onbelangrijke plakkende tape. Zelf heb ik alleen maar succes hiermee gehad. Bron: Sterremuur op het forum audiofreaks.nl Identificatie van reel to reel tapes aan de hand van de aanloopstrook Identificatie van tapes Geen aanloopstrook: tja... wit met paars/blauwe blokjes en 150 = TDK Audua kant 1 wit met rode blokjes en 150 = TDK Audua kant 2 TDK Audua tape is vrij donker van kleur, aanloopstroken vallen er vaak af transparant/wit met zwart raster en LX35 of GX35 = TDK LX of GX kant 1 transparant/wit met rood raster en LX35 of GX35 = TDK LX of GX kant 2 TDK LX kan met en zonder backcoating, erg glad en vrij donker van kleur TDK GX altijd met backcoating, vrij glad en iets lichter van kleur als LX transparant wit met grijze blokjes = Maxell LN/Communicator kant 1 transparant wit met oranje blokjes = Maxell UD tot 1982 kant 1 transparant wit met blauwe blokjes = Maxell UD vanaf 1982 kant 1 transparant wit met blauwe cijfers 50/35/25/18 = Maxell UD vanaf 1988 kant 1 transparant wit met zwarte blokjes = Maxell UDXL kant 1 transparant wit met donkergroene blokjes = Maxell XLI kant 1 transparant wit met donkergroene cijfers 50/35 = Maxell XLI vanaf 1988 kant 1 transparant wit met gouden blokjes = Maxell XLII (EE) kant 1 transparant wit met gouden cijfers = Maxell XLII (EE) vanaf 1988 kant 1 transparant wit met rode/roze blokjes = Maxell kant 2 transparant met kleine, rode stippeltjes: Maxell UD 50/35/25/18 en XLI 50/35 vanaf 1988 kant 2 ruiken allemaal hetzelfde wit met zwarte letters SONY = Sony tape kant 1 wit met blauwe letters SONY = Sony tape kant 1 (blijkt ook voor te komen) wit met rode letters SONY = Sony tape kant 2 groen met zwarte binnenkant en opdruk met cijfers en SPR50, LPR35 of DPR26 = BASF LH Professional kant 1 rood met zwarte binnenkant zonder opdruk = BASF LH Professional kant 2 groen met cijfers en SP50, LP35, DP26 of TP18 met schakelfolie = BASF > zie aanduiding op strook rood zonder cijfers met schakelfolie = BASF kant 2 BASF SP/LP/DP/TP is roodbruin van kleur en heeft een redelijk sterke geur lichtgroen met schakelfolie op de strook = Scotch LP lichtblauw met schakelfolie op de strook = Scotch DP lichtrood/roze met schakelfolie op de strook = Scotch kant 2 Scotch tape is donker/zwart van kleur en heeft een sterke (ietwat zoete) geur. Ook herkenbaar aan de montage van de aanloopstrook aan de tape; deze laat meestal iets los en vouwt om. Dezelfde aanloopstrook komt voor bij Revox tapes. Revox maakt gebruik van Scotch tape en Ampex tape. Plakt het en is het bruin van kleur, dan is het Ampex; plakt het niet of minder en is het donker van kleur, dan is het Scotch tape. donkergroen transparant = Ampex kant 1 donkerrood transparant = Ampex kant 2 geen schakelfolie, tape is bruinig van kleur, met backcoating Bij Maxell staat het getal op de aanloopstrook voor de dikte van de tape in micron. Bij BASF staat het getal eveneens voor de dikte in micron; LP is long play en DP is double play. LPR en DPR: idem maar dan LH Professional. Bij TDK en Sony staat getal voor de lengte van de tape in aantal % t.o.v. een SP (standard play) tape. Standard play lengte bij 26,5cm is 2400 feet, long play is 3600 feet, dus 150% van standard play. (Met dank aan Andreas, die mij dit lijstje ooit eens stuurde ;) ) (bron: analogaudio.nl forum) Tape reference level Old German 320 nWb/m level Reference fluxivity of G320 nWb/m is consistent with the German flux measurements made in the 1950’s that are used in the UK and Europe to this day. The actual fluxivity of these recordings as measured by DIN 45520 or AES7/ANSI S4.6 is 290nWb/m . The original tape flux measurements were made in Germany in the late 1950’s, using a transfer-to-dc method standardized in German Standard DIN 45520. These measurements are the basis for the reference fluxivity of 320 nWb/m used on German calibration tapes made by BASF and Agfa (now a part of BASF). In the late 1960’s Ampex used the ANSI method to measure the German tapes, and found that the German reference fluxivity was not 320 nWb/m, but only 290 nWb/m, which is about 1 dB low. Recent new measurements at MRL have confirmed that flux measurement by the transfer-to-dc method used in Germany gives exactly the same results as the ANSI method. So MRL have concluded that the original (1950’s) German measurement was in error by 10%. The MRL Calibration Tapes made to conform to the old German measurements were previously identified by MRL as “320” nWb/m; this has now been changed to G320 nWb/m, indicating 320 nWb/m according to the original German measurement. Operating Level Flux@1000Hz Flux@700Hz 0dB 180 nWb/m 185 nWb/m +1dB 200 nWb/m +2dB 224 nWb/m +3dB 250 nWb/m 260 nWb/m +4dB 280 nWb/m G320 nWb/m +5dB 315 nWb/m +6dB 355 nWb/m 370 nWb/m +7dB 400 nWb/m +8dB 450 nWb/m G510 nWb/m +9dB 500 nWb/m Magnetic Flux level flux Φ LΦ 520 nWb/m +6.36 dB 370 nWb/m +3.41 dB 320 nWb/m +2.14 dB 250 nWb/m 0 dB 220 nWb/m −1.11 dB 200 nWb/m −1.94 dB 185 nWb/m −2.62 dB 150 nWb/m −4.44 dB 1/4 track machines will respond different that 1/2 track machines. The 1/2 track decks can use 370 nWb/M (+6dB) but the A2300 will not work well with that level. It needs to be no higher than 250 but more correct 200 if you want full bandwidth. Like a lot of guys are oing they get blinded except for one spec and that is flux density. This may enhance S/N ratio but also distortion goes up and bandwidth goes down. So you are better off with a 200nWb/M tape for the A2300 at 7.5 IPS and can also be used on the quad Otari. The 25-2 is not going to like the levels above 250 nWb/M as it is designed and the A7300-2T is better off at 250 as well. If you want to run 370 nWb/M the Tascam 52, 62 and ATR units are more suited and have jumpers for those levels. Higher is not always better! The track width of machines has a lot to do with how much flux you can throw at it. The 1/4 track decks like to have 200nWb/M and on a rare occasion maybe 250 but nothing higher. the 1/2 track machines is where you have many options and depending on the speed you might be able to throw a lot of signal at it. You know the other thing in upping the flux density- the tape has a fixed saturation point let just say +15. If you go and set up a deck for +6(370) instead or +3 (250) then what you risk is a saturation happening sooner as you then do not have +15 headroom but +9. Studer A80 history 1970 "A new generation of the series A80 professional studio tape recorders is introduced in the Spring of this year." * 1971 "A new studio tape recorder, the model A80/R "Broadcasting Version" complements the A80 series. * 1972 "The versatile concept of the professional studio recorder A80 permits its conversion into a quadraphonic model, which is called A80RT-Quadra." * 1975 Studer Canada launched the A80/VU-16-2" at WABE '75 Hotel Vancouver. Bruno Hochstrasser loaned it to Little Mountain Sound (LMS) Vancouver where I worked 1975 Studer Canada A80/VU price list shows "Mk I" 8T-1" and 16T-2" transportable versions 1977 LMS installed the first Studer A80/VU-24-2" Mk II in Western Canada; I worked on this project 1980s A80 Mk III and Mk IV multi-tracks with faster punch-in with a single erase head closer to record head, transformerless I/O, Dolby HX (Mk IV), etc 1989 A80 End of Production ** 1998 A80 End of Maintenance Support by audiohouse.ch GmbH ** I'm unable to find the changeover date from A80/VU Mk I to Mk II, estimate early to mid 1970s as technology and designs improved. Others in this forum might provide more details. I believe serial numbers starting from "10,000" were assigned to Mk II machines to distinguish them from Mk I. A80 VU Mark I has centre-tapped repro heads, black frame VU meters, no removable EQ cards for Rec/Sync/Repro cards as Mk II, etc. Re: A80 sales volume: "The fundamental corporate policy of Studer is to manufacture and market only well-engineered products with a long service life. With over 10,000 sales, the series A80 proves that Studer customers appreciate this policy." *** I'll add that a source of confusion is that the A80 was originally introduced as simply the A80, but was then later re-named the A80/VU. This was done to try to better differentiate it from the subsequently introduced, lower-cost A80/R and A80/RC versions that were developed for the broadcast market. As most readers here know, the A80/R and RC borrowed the earlier developed audio channel electronics from the B62. This was done to make the A80/R and RC versions available at lower cost. Revox PR99 reference level Sam: When I worked at Teac the Technicians had a discussion early on about how the bias should be set and we discussed the two ways to do it. We found and we told later on that the service manual is written for Technicians and often times with the assembly line in mind. Overbias is a fast and sloppy way to do the job to turn out more units from the line. exact calibration It is not found to be the way for exacting calibration. That can only be by either spot frequencies or sweeps as is available on a device like the Audio Precision One plus analyzer. Here the 1KHz and 10KHz are compared and then once those are close to each other further modification allow the frequency response be contoured to go out to extended frequencies such as 31.5KHz at 15 IPS or in some deck 28KHz. Of course you can not hear that but it shows what a machine can do. I have had factory decks come in that would be 3 dB down at 9KHz. factory set Is this what you call Hi Fi? I don't When I got done with the machine it went out to 22KHz at 0 Vu at 7.5 IPS. In all my years of working on decks I have had no negative comments about my calibration process either at Teac or Sony or after. In fact people often tell me they sound better than they were new. I suspect that is correct as they were probably set wrong from the factory which is common. The manufacture only provides you with a deck that works- it does not say it is optimum adjusted. That is why there is such a long list of tape in the manuals as it is set up somewhere in the range of all those tapes- none are perfect. I have not used over bias since 1982. I can send sweep results to those who wish to see them by E mail bit in the past I have already posted some of those. I use plus or minus 2 dB not 3dB. Some machines come out to plus or minus 1dB if it were not for the head bump. NAB vs. IEC NAB The NAB eq curve, used in North America, employs time constants of 3183 usec (50 Hz) for the bass, & 50 usec (3183 Hz) for the treble, at speeds of 7.5 & 15 ips, in playback mode. This spec originated in the early 1950's, when tapes had less HF capability, & bass boost in recording was employed at 50 Hz to avoid LF rumble during playback. IEC The IEC curve came a little later and is a curve which better matches and better utilizes the benefits of improved tapes. It uses an infinite time constant in the bass end (0 Hz), and a 35 µsec (4547 Hz) time constant in the treble region at 15 IPS speed. At 7.5 IPS, bass is the same, but the treble time constant is 70 µsec (2274 Hz) . Again, IEC EQ provides less treble boost in playback (at 15 IPS speed), realizing a slight improvement in S/N ratio over NAB EQ. The difference is about 1.0 to 1.5 dB . At 7.5 IPS speed, NAB provides less treble boost and a little better S/N, 1.0 to 1.5 dB . Compatibility A tape recorded at 15 IPS w/ NAB EQ & played back w/ IEC EQ, will likely sound a little deficient in the treble, as well as in the deep bass. But the amount is not that great, like a dB or so. A tape recorded in IEC, then played back in NAB will have slightly boosted treble & bass. The freq response is not flat this way, but there will always be some listeners who prefer boosted sound at the bass & treble regions. If the recording speed was 7.5 IPS, then IEC provides more playback treble boost than NAB. So the treble response will vary in the opposite direction as above, but still a small difference. Bass remains the same as above. If "flat" is the objective, then it is recommend to play back with the same EQ curve used during recording. Still, the difference is pretty slim, and if the right curve is not available, a parametric or graphic outboard EQ can restore flat response. Use the break frequencies given above and all should be well. Again, if an outboard EQ is not available either, no big deal. The deviation from flat response is too scant to be concerned about. Technics 1500 - 1700 Chris: “The RS-1700 was an update of the iconic RS-1500.” Comment: Just to nitpick, the 1700 was actually kind of an enhancement to the 1506. The RS-1500 and 1502 were near-pro-grade 2-track machines that had a quarter-track play head over on the left side before the erase head. There was a switch on the headblock to control which play head hit the electronics. The machine only recorded in 2-track. The play-head switch was semi-reliable over time but can be cleaned and if it’s treated gently, the contacts just get dirty rather than fail like some 1960’s slide-switches. The RS-1520 was the 1500 with balanced inputs and outputs and bias and equalization trimmers. It was a professional grade 2-track tape recorder, certainly usable for broadcast production and lower-budget music production. The RS-1506 was a quarter-track version of the RS-1500, with a 2-track playback head over on the left above the quarter-track erase head. So then you get to the RS-1700. This was a consumer deck through and through, although a high end one. It was quarter-track (a consumer format) and bi-directions (in other words it would record both forward and reverse, no need to flip reels). It had the same motors and isolated-loop capstan system as the older machines. The heads were smaller and play and record heads were fit in one assembly (not one head like a typical cassette deck, separate heads in one can) so there was room for 6 heads in the same space as the 4 heads on the other decks. I don’t think this was a major compromise as far as performance, I think the 1700 spec’d out close or identical to the 1506. They are really nice decks, just understand they are high-end consumer decks, mainly because of the quarter-track format. Technics reel decks hold their own to this day. They are very gentle on old tapes, but the tension against the heads is low so they are non-ideal for edge-warped old tapes. They are dead-on speed accurate if the motor is working properly. There are electronic tweaks, but making sure all the capacitors are good would be my first repair. By the way, check out this website, showing the OTHER isolated-loop decks Panasonic sold in Japan: http://reeltoreelworld.blogspot.com/2009/02/doc-technics-adds.html The RS-1800 was sold outside of Japan. I’ve heard of some in the U.S. but never seen one. The little 7″ reel deck was only sold in Japan. Note the silver-faced 1700 in one ad. Technics SL-P777 Belt: square. 1,5mm and lenght (flat=7cm) so 14cm, radius=~25mm Laser unit: SOAD70A Technics RS-BX501 belt straal | radius : 36 mm omtrek | circumference : 228 mm diameter | diameter : 73 mm platte lengte | flat length : 114 mm Revox PR99 history The PR 99 is basically the "hot rod" version of the B 77. It's basically the same machine built for semipro applications. XLR connectors and the 19" rack capability as a standard offerings are the most significant differences. Of course, the addition of the auto-locator on the MK ii was a valuable asset for the pro user. It came in 61 versions and were sold for 13 years. A damper pin was added on the right side (the B 77 has only one) and the framed was modified to accommodate the protruding head block. It's widely known that the electronics were fully revised and improved with some features built specifically for pro applications. Marino and his staff were still developing the cassette deck project under constant cost pressure in order to start developing the new project "PR 99". This machine was never designed to be domestic or to be in a living room. It was exclusively called "Revox" and it was highly successful! The PR 99 is the affordable "Studer". It was the bridge between the domestic B 77 and the professional Studer machine. The sales of the PR 99 among the professional circles were really amazing! Three versions were made: MK i, MK ii and MK iii. The MK i and the MK ii, besides the auto locator, are almost the same machine. The MK iii looks different because the bottom panel is gray color and the buttons are plastic. They wanted to give this last version a more "pro console" look, hence the new buttons (they were cheaper, too!). That's all. There's not a significant difference between the ii and iii and built wise has the same frame and construction. People don't understand that many of the so called revisions are in fact looking for improvements and mainly for lowering the production cost as well. That's the case of the MK iii. The 99' came with a metal 19" rack capability, on a cart or in a flight case with speakers for live recording applications. This last version is rare and I have only seen one. It's not of my personal liking as it's bulky, heavy and I wouldn't listen to my recordings through those shitty speakers anyway. The only value I see is from the collector's point of view and nothing else. On the other hand, those with the butterfly heads are more valuable and scarce. From the sonic point of view, it's not better sounding than its 77' cousins and some people insists that the addition of the balanced transformers for the XLR connectors made it worst than better. I don't care as I find both very pleasant and neutral sounding. There's not a significant difference, if any, in sound. That's for sure. Most of the time it just need somebody, from somewhere to say something, and others start repeating the same **** over and over again until soon enough a urban myth is created! 90% of the time people keep saying the same gossip without even hear or confirm it by themselves. That's the usual case in Audio. The other is when Mr. John Doe look at the design and says: "Oh!, there're balanced transformers on the output,so it has to sound bad!", without hearing the machine first. By that time, a prejudice is created and in no time the rest of the world keeps repeating the same **** as well. Period. The latest B 77's were built in Regensdorf at a rate of 175 units daily when the production was in full blast and were branded as "Studer". Many features from the A 77 were still in function in the B 77 and PR 99 as well. The A 77 replaced the now legendary 36 series and came in response to the Japanese market penetration. The A 77 is cataloged as one of the most important reel to reel decks in audio history and no discussion about tape recording in the 70's could be complete without the venerable A 77. Guido Besimo was in charge of the project. Hans Foletti and Herbert Romagna were in charge of the mechanics, Ernst Mathys designed the function control board, the capstan motor was from the genius of Artur Stosberg and the group's leader himself, Besimo, designed the audio circuit. The thing is that this A 77 audio circuit became the ReVox trademark for years to come and it was later used, without significant revisions, on the B 77 and PR 99 ! That's what I call a genuine cornerstone! The real genius of Studer has been to implement professional quality products in domestic models. As a matter of fact: many A 77 and B 77 were constantly used in professional studios and radio stations. Here in Puerto Rico, Radio Oro, kept using their A 77's array for over 30 years when they were finally retired to receive the new digital era. This same story has been repeated over and over again around the globe. I'm sorry but I don't think any model from Japanese brands could ever make the same allegation. I'm not saying those are bad machines. No. That's not what I mean, but there's an imminent truth in all this and that's the fact that ReVox were ahead of its time by far, as the actual longevity and parts availability testifies. You can still order brand new parts for your Revoxes. They were on another league. Revox products were aimed at domestic markets, but most of their machines were used in professional applications. That's how good they are and how much appreciation and acceptance were given by the professionals around the world. Another subject to consider is that, if we take into consideration that perhaps just one model from any Japanese brands were sold in bigger numbers than all the B 77's combined, how many of those still survives today against the Swiss gem? The A-77 and A 700 are still getting refurbished to this date by audiophiles around the world, even after 40 years! Perhaps that's why Studer-Revox products are among the most restored audio components in this hobby and fetching the highest prices in the second hand market. As a matter of fact: many of these machines has been sold for more of what their original prices were 30 years ago! The last B 77 MK ii and PR 99 MK iii left the manufacturing plant in 1997. source: tapeheads.net Otari Mx-55 N-M Tape Transport Track Configuration 1/4" (6.3 mm) Width Tape, 2-track 2-channel, NAB or DIN Stereo Nom. Tape Speed 38.1 & 19.05 cm/s (15 & 7.5 ips) switchableChangeable to 19.05 & 9.5 cm/s (7.5 & 3.75 ips) Speed Accuracy Within ±0.2% Speed Deviation Less than 0.2% Pitch Control ±20% continuously variable control.Percentage or ips readout with 0.01% precision multiturn encoder servo system. Fast Wind Time 60 Hz = 100 s, 50 Hz = 110 s (2,500 ft tape) Reel Size NAB 10.5", 7", 5", EIA (cine), DIN ReelTape Max. Length = 3,280 ft (tape thickness 50 μm) Motor Capstan = DC Brushless Motor, Quartz PLL Controlled Direct DriveReel = AC Induction Motor Head Plug in head block with full access to independent head height, tilt and azimuth adjustment Start Time(Time to reach within twice specified wow & flutter.) 38.1 cm/s = Less than 0.5 s19.05 cm/s = Less than 0.3 s9.5 cm/s = Less than 0.2 s Wow & Flutter(PEAK WTD, DIN45507, IEC Pub.386) 38.1 cm/s = Less than ±0.06%19.05 cm/s = Less than ±0.08%9.5 cm/s = Less than ±0.12% Tape Timer Seven segment LED readout from tachometer/logic measurement circuit; indicates tape time in Hours, Minutes and Seconds. External Speed Control Range -50%, +100% at all speeds (4.8 to 19.2 kHz) VEM Tape Speed +100% with VEM optional accessory and continuous lower speed change accompanying tone change Electronics (Measured with AMPEX #456 tape. 0 dBu 0.775 V)= Line Input 3-pin XL Type Connector (female) Transformerless Active Balanced Input Impedance: 10 kΩ Ref. Input Level: +4 dBu (0 to +10 dBu), -16 dBu (-10 to -20 dBu) Max. Input Level: +30 dBu Mic Input 3-pin XL Type Connector (female) Transformerless Active Balanced Input Impedance: 10 kΩ (20 Hz to 20 kHz) Min. Input Level: -70 dBu Microphone Impedance: 150 to 10 kΩ With Supply Channel (CH1/BOTH/CH2) Selection Switch Line Output 3-pin XL Type Connector (female) Transformerless Active Balanced (bal/unbal. switchable) Output Impedance: 5Ω Ref. Output Level: +4 dBu (0 to +13 dBu), -16 dBu (-7 to -20 dBu) Load Impedance: min. 200Ω Max. Output Level: +26 dBu (bal. load), +21 dBu (unbal. load) Bias and Erase Frequency 150 kHz Magnetic Flux Level MX-55N = 185/250/370 nWb/m (switchable) MX-55D = 250/320/510 nWb/m (switchable) Frequency Response(Rec/Rep. 0 dB = 250 nWb/m) 38.1 cm/s = 30 Hz to 20 kHz ±2 dB (0 dB) 19.05 cm/s = 20 Hz to 18 kHz ±2 dB (-10 dB) 9.5 cm/s = 20 Hz to 10 kHz ±2dB (-20 dB) Frequency Response(Sel-Rep) 38.1 cm/s = 30 Hz to 12 kHz ±3 dB 19.05 cm/s = 20 Hz to 5 kHz ±3 dB 9.5 cm/s = 20 Hz to 2.5 kHz ±3 dB Distortion (38.1 cm/s, 1 kHz, 250 nWb/m) Less than 0.3% Crosstalk MX-55N = min. 55 dB MX-55D = min. 50 dB Depth of Erasure(38.1 cm/s, 1 kHz, 1040 nWb/m) MX-55N = min. 75 dB MX-55D = min. 70 dB Rec/Rep Signal-to-Noise Ratio(30 Hz to 18 kHz BPF, UNWTD) MX-55N NAB 38.1 cm/s, 1040 nWb/m = 69 dB MX-55N NAB 19.05 cm/s, 1040 nWb/m = 71 dB MX-55N NAB 9.5 cm/s, 740 nWb/m = 64 dB MX-55N IEC 38.1 cm/s, 1040 nWb/m = 71 dB MX-55N IEC 19.05 cm/s, 1040 nWb/m = 68 dB MX-55N IEC 9.5 cm/s, 740 nWb/m = 64 dB MX-55D IEC 38.1 cm/s, 1040 nWb/m = 72 dB MX-55D IEC 19.05 cm/s, 1040 nWb/m = 69 dB MX-55D IEC 9.5 cm/s, 740 nWb/m = 65 dB Test Signal Oscillator Frequency 100 Hz, 1 kHz, 10 kHz Sine Wave, switchable Miscellaneous Power Requirement 100/110/117/200/220/240 VAC, ±10%, single phase 50/60 Hz Power Consumption 150 VA Operating Environment Temperature: 5 to 45°C, Relative Humidity: 20 to 80% Storage Environment Temperature: -20 to 45°C, Relative Humidity: 10 to 80% Weight 30 kg Dimensions (W x D x H) 440 x 222 x 488 mm Standard Accessories NAB Reel Adapter 10.5" Empty Reel (MX-55N only) DIN 12" Empty Reel (MX-55D only) Power Cord Fuse 1 A x 2 Fuse 2 A x 4 Fuse 5 A x 1 Fuse 5 A (slow blow) x 1 Lubrication Oil (PZ9E003) Case Foot Operaiton Manual Optional Accessories CB-127-S Remote Controller ZA-81G-S Stand (with Reel Spacer. Tilt Adjustable) ZA-81B-T Stand (without Reel Spacer) ZA-81D-S Reel Spacer (for ZA-81B-T) ZA-5CG Rack Mount Bracket SB-12S Scissors ZA-5CU Fader Control Kit PB-1AXAS VEM (Voice Edit Mode) PCBZA-5CW Proximity Switch Kit ZA-5CX Multi Purpose Phone Jack Kit ZA-5CL Input Transformer ZA-5CM Output Transformer Flux Level Standards JOSEF DORNER From 15 MilliMaxwell to 1,200 NanoWebers Need an explanation? Here's a look at the evolution of fluxivity and level standards. An EYE-CATCHING HEADLINE to attract or confuse the reader? Well, certainly not the latter, because one is often confused enough when trying to understand the data printed on the specification sheets accompanying many tape recorders. We find distortion performance and signal-to-noise ratios referred to 185, 200, 250, or even 370nWb/m. In some cases, flux values as high as 1,000 and even 1,040 nWb/m are mentioned, while Europeans use such odd values as 320 and 514 nWb/m for reference fluxivity. Where do all these different values come from? Maybe some light can be shed on this matter by looking back into the history of magnetic recording. A STANDARD IS CREATED Let's go back about 30 years, to a time when Geman technicians were already talking about a standard tape flux, well before their cohorts on the other side of the Atlantic were. Their definition read something like this: "...for the purpose of program exchange, a reference value for remanent tape magnetization has to be established. When using general purpose tapes, this level shall be approximately 6 dB below maximum output level. (In reality, the span was only 4 dB at that time- author). Fortissimo passages shall modulate the tape up to that reference level. This is of importance for the purpose of program exchange. Only in applications where program exchange is not a criterion, modulation up to 3 percent of third-harmonic distortion may be tolerated; this is in order to achieve a higher signal-to-noise ratio and better utilization of the tape. For class 38 (15 ips) the reference level is set to 200 milliMaxwell and for class 19 (7.5 ips) to 160 milliMaxwell." (Draft for DIN 45 513).[1] Remember this dates back to 1955! In America, all that was known at that time, as far as a recording standard was concerned, was the calibration tape made by a well-known manufacturer of magnetic tape recording equipment (Ampex) with a reference level recorded on it, which was named the "Operating Level." That Operating Level was used to calibrate the VU-meter to obtain a 0 VU deflection. By digging a little deeper, one was able to learn that this Operating Level corresponded to 1 percent of third-harmonic distortion on the then most widely used (general purpose) recording tape in the USA. MOL AND THE VU METER At this point it may be of interest to note that this general purpose tape produced 3 percent of third-harmonic distortion when it was modulated to a point some 6 dB above Operating Level. Many a studio (particularly some European studios) - where the VU-meter started to make its appearance in the early '60s - may have been misled by this fact to think that a VU-meter has to be operated with a 6 dB lead. By 1966, however, the Deutsche Industrie Normen (DIN) had already recognized that this was not quite correct, because it is stated in the explanatory note accompanying DIN 45 406 that "....on average the lead required is about 8 dB (8 VU). Deviations from this average by ±5 dB, however, are not exceptional." If one compares this with the old RETMA TR 105 B standard (1951) for Audio Facilities for Broadcasting Systems, one can read the following in section V.2.a: "If a VU-meter is incorporated, it shall remain as normally connected, and its multiplier shall remain set for a signal which is 10 dB below standard output level" (Standard output level is +18 dBm). Can one not conclude from this that signal peaks, as recorded on tape, produced flux values up to some 8 to 10 dB beyond the 1 percent distortion level, in other words, far in excess of the 3 percent distortion point? Yes, because in 1965 the NAB standard for reel-to-reel recordings has the following to say in a footnote to section 2.04, which relates to the standard reference program level: "It is well established that at least 10 dB margin is required between the sine wave load handling capacity of a system and the level of program material as measured by a standard volume indicator." The NAB standard reference level is described in section 2.03 with a footnote which reads as follows: "The recording was made... at an output level 8 dB below that which produces 3 percent third-harmonic distortion." (This is not contradictory to the above statement because it simply defines a level of tape magnetization which is to serve as a reference.) So, where do we go from here? THE AMERICAN REFERENCE FLUX Fortunately, John McKnight in the United States seemed to have been bothered by this lack of a precise value for recorded tape flux. As a consequence, he investigated this situation and prepared his findings for publication in the Journal of the Audio Engineering Society.[2] A reference flux of 100 nWb/m is mentioned or suggested in that investigation, and one reads for the first time 210 nWb/m for the earlier discussed Operating Level and 165 nWb/m for the NAB Standard Reference Level. Later on, these values were downward corrected slightly, and from a 1972 data sheet of a manufacturer of calibration tapes, one can read 185 nWb/m for the Operating Level and 150 nWb/m for the NAB Reference Level. At this point, we should pause to take a closer look at the units of measurement. UNITS OF MEASUREMENT NanoWeber-per-meter is the value of fluxivity that would be measured if the tape was 1 meter (or approximately 39 3/8 inches wide. Reducing this to a more realistic width, namely 1mm (or 39 mil), the unit became picoWeber-per-millimeter, which was 0.1 milliMaxwell per millimeter in the days before the ST units came into force. In the case of the NAB Reference Level, the result is 15 mM/mm, which explains one of the values mentioned in the title of this article. Since we are already doing some calculations, let's look at the previously mentioned German reference of 200 milliMaxwell for 1/4-inch tape. If we divide that figure by the metric equivalent of 1/4 inch, which is 6.25 mm (tapes today are 6.3mm wide), then we get the figure of 32 mM/mm. Converting this to nanoWebers, we arrive at the standard 320 nWb/m. It may be worth mentioning at this point that in a comparison of U.S. and European levels one must be aware of the fact that the ANSI S 4.6 method of measuring remanent flux yields a value which is lower by 0.8 dB, as compared with a measurement performed in accordance with DIN 45 520. In practice, this means that when comparing calibration tapes of U.S. and European origin, the U.S. tape will yield a higher signal level because what is 200 nWb/m in the U.S. would measure 220 nWb/m in Europe. (This also explains the previously cited downward correction from 165 to 150 nWb/m.) STEREO-MONO COMPATIBILITY After this digression into levels and their history, let's continue on. Magnetic oxides were improved over the years, making higher levels of magnetization possible without adversely affecting distortion performance. This made it feasible to raise the operating level (0 VU) to 250 nWb/m for the so-called High Output tapes. In Europe (more precisely in Germany), the advent of stereo made those exacting engineers reach for their slide rules, because stereo/mono level compatibility was their goal. Music productions were already recorded in stereo, yet broadcasts were still in mono. Such a stereo recording, when played back on a full track head, did not produce the same signal level as that which resulted when playing a mono recording; there was some unused, unmagnetized "land" between the stereo tracks, and left and right signals were not adding up algebraically. One can live with reduced cross-talk performance in stereo, so the tracks were widened until they were spaced only 0.75mm apart, making each track 2.75mm wide. As a result of this, the core sections of the head spread out at an angle to accommodate the windings. With this, the Butterfly Head was born (see FIGURE 1). Figure 1. Butterfly head The tape's width was utilized to a possible maximum, but stereo/mono level compatibility was still not reached. A few quick calculations and one can see that a stereo recording has to be modulated to 514 nWb/m in order to produce the same signal level as that which is obtained from a 320 nWb/m mono recording when playing the stereo tape on a monophonic reproducer. Total flux, mono on 1/4-inch (6.25mm) tape: 320 nWb/m x 6.25 = 2000 nWb/m Stereo played on full track head: Formula.gif The goal was reached: The fader on the mixing desk did not have to be moved, regardless of whether mono or stereo recordings were played! At the time it was a bit strange, perhaps, to see blank tape appearing on the market which was labelled "stereo," though this simply meant that such a tape could be modulated to the higher stereo level without any increase in distortion. Stereo/mono compatibility - which is not of much interest anymore - is thus explained, but what about universal compatibility of recorded levels in general? VU VS. PPM AND PEAK FLUXIVITY In America the VU-meter is still favored while in Europe the peak program meter (PPM) is predominant. The performance characteristics of the latter are described and specified in IEC 280-10 and in DIN 45 506. It is a quick-acting meter, and because of this, it is also called a "quasi peak-reading meter." However, as suggested by the word quasi, it is not a true peak-indicating device. A closer examination of its characteristic behavior suggests that short modulation peaks may overshoot by 1 to 4 dB.[3] A graphic presentation (FIGURE 2) of the maximum output level performance (MOL) of various tapes, including the most modern oxides, shows how tape performance has improved over the years. The point of maximum modulation, which is universally considered to be the level at which the third-harmonic distortion content measures 3 percent,[4] has shifted gradually to higher flux values, with 1,200 nWb/m being reached by at least one state-of-the-art tape. This explains the second figure in the title. Quite a wide range from the NAB reference of 150 nWb/m via the high-output operating reference to the German DIN levels for mono and for stereo, up to the MOL which is possible today. Figure 2. Maximum Output Level (MOL) performance of magnetic recording tapes at 15ips. O= Theoretical peak flux values when aligning VU meter or PPM as described in text The dashed line (1955} represents the performance of the old U.S tape if flux values were measured in accordance with DIN. Attempts to establish references of even figures have been repeatedly made. For example, there is the EIA standard RS-400/1972 containing a reference to CCIR 79-1/1966 at which time the value of 100 nWb/m was recommended, and in more recent times, one finds 400 nWb/m mentioned in a newer EIA standard. But all this is of little help to a studio's maintenance engineer when faced with the decision of how he should calibrate his level meters. So, in analyzing this historical retrospect it comes almost as an automatic conclusion that 250 nWb/m (or even 320 nWb/m) would be a good reference for calibrating a VU-meter to its 0 VU reference deflection, as it would allow the modulation peaks to reach up to 800 or 1,000 nWb/m. In the case of a quasi peak-reading meter or PPM, however, the 510 nWb/m (or 500 for simplicity's sake, being twice 250) would be an equally good reference because its assumed 4 dB overshoot would again result in a peak magnetization in the range of 800 nWb/m, still well below the accepted MOL of 3 percent third-harmonic distortion. It's up to the individual engineer's discretion, of course, as to how hard he intends to drive his tape into saturation. It should be borne in mind, however, that for every dB gained in signal-to-noise, one must pay with a disproportional increase in distortion, a fact which was discovered long ago by a pioneer in the development of new recording techniques.[5] Analog recording may still be around for a while, and so it is hoped that useful conclusions can be drawn from this article which help to ensure that the inherent quality of analog is not given away unwisely, as may all too often be the case. Output Level vs. Flux (taken from the Studer 820 Service-Manual) References 1. Krones, Dr. F. "Herstellung und elektroakustische Eigenschaften der AGFA Magnetbander, Filme und Bezugsbänder." Sonderdruck aus den Forschungslaboratorien der AGFA Leverkusen. Band I. (Nov. 1955), Seite 304. 2. McKnight. John G. "Absolute Flux and Frequency Response Characteristics in Magnetic Recording." Preprint 447. 31st AES Convention. Oct. 1966. Published in revised form: Journal of SMPTE Vol. 78. (June 1969), pp 457-472. 3. Silver. Sidney L. "VU-Meters vs Peak Program Meters." db (Jan. 1980). pp 46-49. 4. DIN 45 511. "IEC Draft 94-5." NAB Magnetic Recording And Reproducing Standards (1965), Section 2.11: Distortion. 5. Langevin, Robert Z. "Intermodulation Distortion in Tape Recording." Journal AES (July 1963). Vol. 11. pp 270-278. aus: db magazine July 1984 pp 36-38 Use NAB test tape to calibrate IEC deck and vice versa Use an NAB test tape to calibrate an IEC deck Play the NAB tape on the IEC deck. I am assuming a 15 ips speed. Play a 1K test tone on the deck and make that your zero reference. Play the 8K tone and adjust for -2.5dB relative to your 1K tone. Play the 50Hz tone on the tape and adjust for a +3 dB level if your test tape has fringing compensation. If no fringing compensation, adjust for +4 dB level. or the opposite Use 1K or 500Hz for your zero reference. Play 8K tone and adjust for +2.5 dB Play 50 tone and adjust for -3 dB (if your tape has fringing compensation. If no FR, adjust for -2 dB) (+2.7 dB for 10K) Revox B215 De Revox B215 is een cassettedeck die van 1985 tot ongeveer 1990 door Studer werd geproduceerd . Een professionele versie met een andere bedieningsindeling en audiopadelektronica werd gelijktijdig geproduceerd als de Studer A721 . Een later verbeterde versie werd op de markt gebracht als de Revox B215S . Omdat hij duurder was in vergelijking met andere consumentenmodellen en uitzonderlijk goede mechanische prestaties en duurzaamheid had, werd de B215 voornamelijk gebruikt door professionele klanten: radiostations, opnamestudio's en realtime [ a ] cassette-duplicators. Revox B215 cassette deck De B215 maakte gebruik van een beproefd, betrouwbaar bandtransport met vier motoren, afgeleid van het eerdere model B710. De B215 onderscheidde zich van de B710 en concurrerende decks uit die tijd door een ongebruikelijk, computerachtig bedieningspaneel en uitgebreide automatisering, uitgevoerd door drie Philips- microcontrollers . Het deck was uitgerust met automatische bandkalibratie, microcontroller-ondersteunde instelling van opnameniveaus en niet-vluchtig geheugen . De objectieve, onafhankelijk gemeten en geverifieerde specificaties van de Revox evenaarden of overtroffen die van de beste concurrerende decks; vergelijkende tests plaatsten de B215 op hetzelfde niveau als de Nakamichi Dragon en boven de vlaggenschipmodellen van ASC, [ b ] Harman Kardon , Tandberg of TEAC . Recensenten prezen de Revox om zijn voorbeeldige mechanische kwaliteit en de verwachte duurzaamheid van zijn tapetransport, maar bekritiseerden hem om een ​​lager dan verwacht dynamisch bereik en tekortkomingen in bruikbaarheid . Ontwikkeling en productie Studer AG , een particuliere Zwitserse fabrikant van professionele audioapparatuur, begon eind jaren zeventig met de ontwikkeling van high-fidelity cassetterecorders . Willi Studer aarzelde om te diversifiëren naar de zeer concurrerende markt voor cassettedecks; gedurende het grootste deel van het decennium beperkte de ervaring van het bedrijf op het gebied van cassettetechnologie zich tot betrouwbare, maar low-fidelity apparatuur voor in het klaslokaal. [ 1 ] [ 2 ] De daling van de verkoop van spoelenrecorders , het commerciële succes van Nakamichi en de " designermodellen " van Bang & Olufsen , in combinatie met druk van binnenuit het bedrijf, overtuigden Studer er echter van om te investeren in het cassetteformaat. [ 2 ] Marino Ludwig, ontwerper van de Revox B77 spoelenrecorder, [ 3 ] onderzocht de beste cassettedecks op de markt en adviseerde Studer over een handelwijze. [ 2 ] Studer ging akkoord met het voorstel en benoemde Ludwig tot hoofd van het cassetteproject, op voorwaarde dat de reputatie van de merken Studer en Revox op geen enkele manier in gevaar zou worden gebracht. [ 2 ] In september 1980 presenteerde Studer AG zijn eerste cassettedeck, de Revox B710 ; in 1981 werd deze vervangen door de bijna identieke Revox B710 MKII, die Dolby C- ruisonderdrukking toevoegde. In 1982 introduceerde het bedrijf een professionele versie, de Studer A710, uitgerust met gebalanceerde ingangen en uitgangen . [ 4 ] In de Verenigde Staten kostte de B710 MKII $ 1995, [ 5 ] meer dan de rivaal Nakamichi ZX7 ($ 1250), maar minder dan het vlaggenschip Nakamichi 1000ZXL ($ 3800 voor de basisversie, [ 6 ] of $ 6000 voor de "gelimiteerde" editie. [ 7 ] ) De B710 met drie koppen werd ontworpen en gebouwd volgens de normen van professionele reel-to-reel decks; zelfs het frontpaneel en de bedieningselementen werden geleend van de B77-recorder. [ 2 ] De B710 onderscheidde zich van de concurrentie doordat hij een echt viermotorig direct-drive tapetransport had : elk van de twee capstans en de twee spoelen werden aangedreven door hun eigen elektromotor zonder tussenliggende riemen , tandwielen of meelooprollen . [ 2 ] Er waren geen remblokken , riemen, katrollen of tandwielen in het hele transport; zelfs de tapeteller werd aangedreven door een opto-elektronische encoder op de spoelmotoren. Mechanisch gescheiden opname- en afspeelkoppen waren elk instelbaar, maar er was geen voor de gebruiker toegankelijke azimutregeling . De B710 was mechanisch solide, maar miste functionaliteit; belangrijker nog, het deck miste voor de gebruiker toegankelijke tapekalibratieregelaars. Over het algemeen was het ontwerp zeer conservatief. [ 1 ] Marino Ludwig schreef dat de ontwikkeling samenviel met een stortvloed aan nieuwe functies ( Duits : der Flut von Neuheiten ) geïntroduceerd door de Japanners, en slechts een paar, zoals automatische tapetypeherkenning, konden binnen de deadline worden geïmplementeerd . [ 1 ] Niet-geteste nieuwigheden die het product in gevaar konden brengen, zoals dynamische voorspanning , werden van begin af aan afgewezen. [ 1 ] In 1984 ontwierpen Ludwig en Meinrad Liebert een opvolger van de B710, de B215. [ 2 ] De eerste pre-productiebatch werd eind 1984 geassembleerd; de eerste productiedecks werden begin 1985 naar dealers verzonden. [ 8 ] Een professionele afgeleide, de Studer A721, leek sterk op de B215, maar was uitgerust met gebalanceerde in- en uitgangen en traditionele draaiknoppen voor het volume in plaats van omhoog-omlaagknoppen. De pers plaatste de B215 op gelijke voet met de beste concurrerende decks, en beoordeelde de geluidskwaliteit als hoog, of bijna zo hoog als die van het nieuwe referentiedeck - de Nakamichi Dragon . In de Verenigde Staten kostte de B215 aanvankelijk 'slechts' $ 1390, [ 9 ] lager dan zowel de B710 als de Dragon. 'Betaalbare' prijzen en robuust transport maakten de B215 het deck bij uitstek voor real-time [ a ] ​​cassetteduplicators; Zo exploiteerde het in Vermont gevestigde Revolution Audio in april 1986 een vloot van 200 B215's, 24 uur per dag, vijf dagen per week, en was het van plan er nog eens 200 aan te schaffen. [ 10 ] Het Duitse audiotijdschrift gebruikte een stapel van tien B215's om zijn eigen testcassettes te dupliceren. [ 11 ] Ludwig schreef dat de prijsdaling de kostenbesparingen weerspiegelde die bereikt werden door het gebruik van grotere printplaten en geautomatiseerde assemblage . [ 12 ] De introductie van de B215 viel ook samen met een recordlage wisselkoers van de Zwitserse frank ten opzichte van de Amerikaanse dollar, die in februari en maart 1985 een historisch dieptepunt bereikte. [ 13 ] Vervolgens steeg de wisselkoers van de Zwitserse dollar gestaag, [ 13 ] en zo ook de Revox-prijzen in Noord-Amerika. In 1989 kostte de B215 $ 2400, [ 14 ] en in 1991 $ 2600. [ 15 ] De verbeterde, cosmetisch herontworpen B215S, geïntroduceerd in 1989, kostte $ 2800–$ 2900 [ 14 ] [ 15 ] — meer dan de Dragon, en drie tot vier keer meer dan hedendaagse vlaggenschipdecks van Onkyo , Pioneer of Sony . [ 15 ] Tegen die tijd was Willy Studer met pensioen; in 1990 verkocht hij het bedrijf en in 1994 werd het een dochteronderneming van Harman International . [ 16 ] De nieuwe cassettedecks van het merk Revox die onder Harman-management werden verkocht, de consumenten-H11 en de professionele C115, [ 17 ] waren in feite omgedoopte Philips FC-60 / Marantz SD-60-modellen en hadden niets gemeen met de Revox-modellen uit het verleden. [ 18 ] Klassieke vlaggenschipdecks uit de jaren tachtig, zoals de B215, de Dragon of de Tandberg 3014, werden niet meer geproduceerd zonder vervanging. [ 19 ] Verdere verbeteringen van het cassettegeluid vereisten, indien überhaupt mogelijk, aanzienlijke investeringen in onderzoek, maar de bedrijfsmiddelen waren al toegewezen aan digitaal. [ 19 ] Ontwerp en werking Uiterlijk en ergonomie Achteraanzicht van het bandtransport. Twee bronzen vliegwielen onderin zijn rotors van de capstanmotor. Daarboven bevindt zich de solenoïde die het kopsubchassis (midden) optilt en de bijbehorende demper (links, zwart). De B215 is, net als alle Revoxes uit de B-serie, groter dan het typische hifi-onderdeel uit die tijd. [ 20 ] De behuizing meet 45 bij 15 bij 33 centimeter (17,7 inch × 5,9 inch × 13,0 inch) [ 20 ] en is een standaard Studer geperste stalen kast met twee interne verstevigingsrails die het tapetransport dragen. [ 21 ] [ 22 ] Het ontwerp van het voorpaneel volgt de stijl van de B200-serie, die in 1984 werd geïntroduceerd met de release van de B225 cd-speler. [ 23 ] De bedieningselementen voor het tapetransport en de opnamemodus, die op de bovenste aluminium strip zijn geplaatst, zijn visueel gescheiden van secundaire knoppen. [ 23 ] Het laden van de cassette in een open transport gebeurt in twee bewegingen: eerst wordt de bovenrand van een cassette ingebracht, vervolgens wordt de onderkant van de cassette ingedrukt totdat deze vastklikt. [ 21 ] Dit levert geen probleem op bij dagelijks gebruik. [ 21 ] Open tapetransport is minder gevoelig voor azimutscheefstand dan typische gesloten-dekseltransporten, en vereenvoudigt routinematige reiniging en demagnetisatie. [ 21 ] [ 24 ] De opnameniveaus, de opnamebalans en het hoofdtelefoonvolume worden elektronisch ingesteld met behulp van omhoog-/omlaagknoppen. [ 25 ] [ 26 ] Er zijn geen microfooningangen; ontwerpers achtten die overbodig voor een consumentenproduct. [ 22 ] De markering op het paneel is volgens recensenten van het tijdschrift Audio (USA) exemplarisch: zwarte letters op geborsteld aluminium en witte letters op donkergrijs plastic zijn groot genoeg en vanuit elke kijkhoek gemakkelijk leesbaar. [ 27 ] Het belangrijkste lcd-scherm met achtergrondverlichting is daarentegen te klein, te donker en te moeilijk leesbaar. [ 28 ] [ 24 ] Een ander gebrek aan bruikbaarheid is de afwezigheid van controlelampjes op het voorpaneel; zelfs het kritieke rode lampje 'Record On' ontbreekt (het werd later toegevoegd aan de Studer A721, maar niet aan de B215). [ 28 ] Door deze eigenaardigheden is het lastig om de Revox in een donkere kamer te gebruiken. [ 28 ] Recensenten merkten ook op dat het gebruik van digitale bedieningsknoppen in plaats van draaipotentiometers over het algemeen onhandig was [ 24 ] ( dit laatste kwam weer terug op de Studer A721, maar niet op de Revox-decks). Bandtransport Typisch dubbel-capstan-bandtransport uit de jaren 80 gebruikte alleen directe aandrijving voor de voorste (trekkende) capstan; [ 29 ] de achterste (remmende) capstan zou door een riem worden aangedreven op een iets lagere snelheid om de tapespanning binnen de gesloten lus te garanderen, [ 29 ] waardoor er nauw contact tussen alle drie de koppen en de tape wordt gegarandeerd (de drukpad van de cassette kan slechts één kop bevatten), en de tape mechanisch wordt losgekoppeld van de behuizing van de cassette. [ 29 ] Een Revox-deck werkt anders en drijft elke capstan rechtstreeks aan met zijn eigen motor, uitgerust met een enorm vliegwiel en een 150-polige snelheidssensor. [ 30 ] De snelheid van elke motor wordt geregeld door een fasevergrendelde lus ; beide lussen zijn gesynchroniseerd met een gemeenschappelijke kristaloscillator . Volgens Studer werd elke capstan bewerkt met een precisie van 1 μm (0,001 mm of 0,000039 inch), om zeer lage wow en flutter te garanderen. [ 31 ] [ c ] In 1985 was het enige andere dek met een soortgelijke directe aandrijving de vijfmotorige Nakamichi Dragon (de dichtstbijzijnde concurrent, de viermotorige Tandberg 3014, gebruikte één enkele kaapstandermotor). [ 32 ] Twee andere motoren van de B215, diep in het mechanisme begraven, drijven de spoelen van de cassette rechtstreeks aan. Motoren, capstans en spoelspindels zijn gemonteerd op twee spuitgietchassisplaten, stevig aan elkaar geschroefd; koppen en aandrukrollen zijn gemonteerd op een bewegend spuitgietsubchassis. [ 31 ] [ 33 ] [ c ] Alle vier de motoren worden elektromagnetisch geremd; er zijn geen mechanische remblokken of frictiewielen. [ 33 ] [ c ] Autostop wordt geactiveerd met een opto-isolator die de aanwezigheid van transparante aanloopband detecteert . [ 27 ] Het opwinden van een band van 90 minuten duurt niet langer dan 75 seconden, [ 20 ] [ 28 ] bij een constante lineaire bandsnelheid. [ 34 ] Als de microcontroller om welke reden dan ook een abnormaal hoge bandspanning detecteert, verlaagt hij onmiddellijk de opwindsnelheid. Aan het einde van de spoel wordt de bandsnelheid geleidelijk verlaagd om impact op het einde van de band te voorkomen. [ 34 ] [ 22 ] Volgens Howard Roberson van het tijdschrift Audio (VS) was de werking van een nieuw B215-transport "...erg stil, zelfs in de afspeelmodus - misschien wel het stilste van alle tot nu toe geteste decks... zeer goed gebouwd, met een duidelijke uitstraling van betrouwbaarheid op de lange termijn". [ 21 ] De B215 gebruikt sendust- en ferrietkoppen van Canon (de B710 gebruikte Sony-koppen, de Revox reel-to-reel-koppen werden door Studer zelf vervaardigd). [ 35 ] De afspeelkop heeft een smalle magnetische opening, de opnamekop heeft een brede opening, maar de exacte breedtes van de openingen zijn niet bekendgemaakt. [ 2 ] [ 22 ] In tegenstelling tot de B710 zitten de opname- en afspeelkoppen van de B215, en een isolatiewig ertussen, strak tegen elkaar aan en kunnen niet afzonderlijk worden afgesteld. [ 22 ] Recensenten van Audio and Modern Electronics merkten een exemplarisch laag faseverschil op tussen het linker- en rechterkanaal (interchannel time error, ICTE), wat een teken was van een zeer goede uitlijning van de opname- en afspeelopeningen en een verwaarloosbaar lage relatieve azimutfout. [ 36 ] [ 37 ] Audiopad Het audiopad beslaat drie printplaten, die elk de volledige diepte van de behuizing beslaan. Van boven naar beneden: opnameprintplaat, afspeel- en besturingsprintplaat, Dolby-printplaat. Het signaalpad van de B215 is vanaf de grond af ontworpen voor gebruik met Dolby C- ruisonderdrukking. [ 12 ] De gebruikershandleiding adviseerde dat "het selecteren van ruisonderdrukking voor nieuwe platen eenvoudig is: gebruik [alleen] Dolby C". [ 38 ] Het deck maakt gebruik van vier Hitachi HA12058 Dolby B/C IC's in een "dubbele Dolby"-configuratie met onafhankelijke coderings- en decoderingskanalen. [ 39 ] Het tapetype wordt automatisch gedetecteerd, maar de gebruiker kan het tapetype handmatig overschrijven en selecteren. Dit omvat een optie om Type II (maar geen Type IV) tapes op te nemen met een equalizer van 120 μs, [ 40 ] wat wellicht de voorkeur geniet bij het opnemen van signalen met sterke hoge tonen, ten koste van meer ruis. [ d ] De B215 replay head-versterker gebruikte een discrete JFET- ingang en een bipolaire tweede trap; deze stuurt de equalizertrap aan - een actief filter gebouwd rond een operationele versterker in inverterende configuratie . [ 41 ] Subtiele fasecontrolenetwerken in het actieve filter werden afgestemd op de best mogelijke staprespons ; Ludwig schreef dat ze " blokgolfreproductie van de tape van werkelijk professionele kwaliteit" mogelijk maakten. [ 12 ] Het signaal gaat vervolgens door een CMOS- schakelaar naar de Dolby-decoder en vervolgens door een andere CMOS-schakelaar naar de uitgangsbuffertrap. [ 41 ] Een derde set CMOS-schakelaars wordt ingeschakeld om een ​​tijdconstante van 70 μs te selecteren in plaats van de standaard 120 μs; als gevolg hiervan gaat het signaal tijdens het afspelen door twee of drie CMOS-schakelaars, plus de schakelaars in de Dolby-decoder. [ 41 ] De schakelaars injecteren onvermijdelijk hun eigen vervormingsproducten in het signaal; hun prestaties kunnen worden verbeterd door vervanging van de standaard 14000-serie schakelaars voor nieuwere pin-compatibele IC's met lage impedantie. Het lijnuitgangsniveau is vast en ongebruikelijk "heet" voor consumentenaudio: 775 mV RMS voor een nominaal magnetisatieniveau van 250 nWb/m. [ 42 ] De hoofdtelefoonuitgang heeft acht selecteerbare volume-instellingen, wat voldoende is voor praktisch gebruik. [ 20 ] Het opnamepad van de audio, dat een eigen printplaat in beslag neemt, is veel complexer. Er zijn drie elektronische niveauregelaars, in serie geschakeld. Continu variabele fade-in en fade-out wordt uitgevoerd door een analoge transconductantieversterker . [ 43 ] Signaalniveaus bij de ingang van de Dolby-encoder ("opnameniveau") en bij de uitgang ("tapegevoeligheid") worden geregeld door 8-bits vermenigvuldigende DAC's . [ 43 ] Ten slotte selecteert een CMOS- multiplexer , gekoppeld aan een laag-Q banddoorlaatfilter gecentreerd op 4 kHz, de gewenste middentonen- equalisatie-instelling. [ 43 ] Nog een andere set 8-bits vermenigvuldigende DAC's, gekoppeld aan een niet-uitschakelbaar Dolby HX Pro- circuit, stelt de gewenste biasstroom in. [ 43 ] Dolby dynamische biasing verbetert, volgens Stereo Review , de verzadigingsniveaus van de hoge tonen met ongeveer 6 dB. [ 44 ] Microcontrollers en embedded software Drie Philips MAB8440 microcontrollers en EEPROM (rechts, met papieren label) De besturingsfuncties van het deck zijn verdeeld over drie identieke Philips MAB8440- microcontrollers [ 12 ] , die worden geklokt met een gemeenschappelijke6 MHz kristal . [ 45 ] Elke microcontroller draagt4 kB programmageheugen en 128 bytes RAM . [ 45 ] De eerste microcontroller controleert het frontpaneeltoetsenbord, de infraroodafstandsbedieningspoort en een optisch ontkoppelde RS-232- poort; de tweede bestuurt de motoren en berekent realtime tapetellerwaarden. De derde microcontroller beheert de digitaal-naar - analoogconverters , CMOS-switches, multiplexers en de opnameniveaumeter; hij voert het tapekalibratieprogramma uit en slaat de huidige instellingen op in niet-vluchtig geheugen . [ 12 ] Het EEPROM wordt bijgewerkt bij elke overgang naar de stand-bymodus of wanneer de gebruiker op een speciale "store"-knop drukt. [ 46 ] [ 47 ] De microcontrollers, display en DAC-drivers zijn verbonden met de I²C seriële bus, [ 45 ] die begin jaren tachtig door Philips werd geïntroduceerd; volgens Ludwig was een gestandaardiseerde bus een vereiste voor een project van een dergelijke omvang. [ 12 ] De B215 is uitgerust met een unieke realtime tapeteller. [ 48 ] Nadat de gebruiker een cassette heeft geplaatst (teruggespoeld of niet) en op de afspeelknop heeft gedrukt, schat de ingebouwde software de huidige tapepositie door de hoeksnelheden van de cassettespoelen te vergelijken. [ 48 ] De eerste schatting duurt 5–8 seconden. Het deck schat ook de volledige speelduur van een cassette, zij het met onzekerheid; om de foutmarge te verkleinen, kan de gebruiker de speelduur handmatig instellen op 46, 60, 90 of 120 minuten. [ 48 ] Met deze prompt, volgens recensenten van Audio magazine, bedraagt ​​de absolute fout niet meer dan één minuut voor een C90-cassette. [ 20 ] De transportbesturingssoftware van de B215 heeft een eigenaardige eigenaardigheid waardoor het volledig terugspoelen van de tape onmogelijk is. Nadat het deck het terugspoelen heeft voltooid, of nadat de gebruiker een reeds teruggespoelde cassette heeft geplaatst, controleert de B215 op de aanwezigheid van ondoorzichtige magneetband in het tapekanaal. Als de opto-elektronische sensor transparante aanloopband detecteert, spoelt het deck de tape langzaam vooruit totdat de sensor ondoorzichtige tape tegenkomt; deze functie kan niet handmatig worden uitgeschakeld. Het deck is dan klaar voor afspelen of opnemen, hoewel het uitvoeren van automatische kalibratie aan het begin van de magneetband ongewenst is; de gebruiker moet de tape handmatig doorspoelen naar een willekeurig punt halverwege de rol, daar kalibratie uitvoeren en handmatig terugspoelen. [ 49 ] [ 20 ] Tape-kalibratie In 1985 werd tapekalibratie, die ontbrak in de Revox B710, de facto de standaardfunctie in de industrie voor topmodellen. [ 50 ] [ 51 ] Reel-to-reel recorders hadden dit niet nodig omdat de kwart-inch tapetechnologie zich langzaam ontwikkelde, de tapes op de markt zeer vergelijkbare magnetische en elektroakoestische eigenschappen hadden, en omdat opnemen op hoge snelheid per ontwerp minder gevoelig was voor variaties in de tape-eigenschappen. [ 50 ] Cassettetapetechnologie ontwikkelde zich daarentegen snel en nieuw ontworpen premiumformules verschilden consequent van IEC-referentiebanden of de oudere, goedkopere tapes. [ 50 ] Het probleem bestond al in 1983: de B710, die in de fabriek was afgestemd op TDK SA-X ferricobalt Type II-tape , had een uitgesproken hogetonenverval bij opname op zuiver chroom IEC Type II-referentiebanden . [ 52 ] Meinrad Liebert bekritiseerde de IEC omdat deze geen strikte normen had opgelegd: de organisatie volgde simpelweg de markt en paste periodiek haar set referentietapes aan willekeurig gekozen "industriegemiddelden" aan. [ 50 ] De ongecontroleerde verspreiding van incompatibele cassettes maakte traditionele cassettedecks met vaste bias vrijwel onbruikbaar voor opnames; dit verklaarde volgens Liebert de plotselinge vraag naar kalibratiefuncties die in de jaren zeventig niet bestonden. [ 50 ] Het ontwerpteam van Revox koos voor geautomatiseerde kalibratie, hoewel de toen gangbare handmatige kalibratie niet alleen goedkoper, maar ook robuuster was. Een menselijke operator heeft een inherent voordeel bij het omgaan met onvermijdelijke drop-outs, transiënten en langzame fluctuaties in de gevoeligheid van de tape; [ 53 ] [ 51 ] volledig automatische kalibratie kon vaak niet omgaan met willekeurige onregelmatigheden en kon verschillende "optimale punten" voor dezelfde tape genereren. [ 53 ] Van de drie of vier beschikbare kalibratiestrategieën koos Liebert de meest flexibele en robuuste benadering van constante hoge tonen-equalisatie - waarbij de bias en het opnameniveau werden aangepast terwijl de equalisatie van het opnamekanaal ongewijzigd bleef, met een extra aanpassing van de frequentierespons rond de 4 kHz. [ 53 ] In tegenstelling tot de meer gebruikelijke tweetonige opstelling gebruikte de Revox dus drie testtonen [ 12 ] (de exclusieve Nakamichi 1000ZXL gebruikte er vier [ 7 ] ). Hoewel Studer er de voorkeur aan gaf deze functie alignment te noemen , heeft dit alleen invloed op de elektronica van het opnamepad en voert het geen mechanische uitlijning uit. [ 47 ] In het voorjaar van 1985 werd de kalibratiesequentie door testers van het tijdschrift Audio reverse-engineered , [ 21 ] en twee jaar later publiceerde Liebert een beschrijving van het algoritme uit de eerste hand: Grove aanpassing van de bias (17 kHz testtoon); Gevoeligheidsinstelling ("niveau") (400 Hz testtoon); Fijne afstelling van bias (17 kHz testtoon); Aanpassing van de middentonen-equalisatie (4 kHz testtoon). [ 53 ] De B215 past de bias en gevoeligheid afzonderlijk aan in elk kanaal, en de midrange-equalisatie wordt gelijktijdig in beide kanalen uitgevoerd. [ 54 ] De bias en gevoeligheid worden ingesteld met 8-bits DAC's met behulp van een binair zoekalgoritme , zodat elk van de zes aanpassingen slechts acht elementaire metingen in beslag neemt. [ 53 ] Bij 400 Hz duurt elke meting ongeveer 0,4 s: 0,1 s om de tape van de opnamekopopening naar de afspeelkop te laten lopen, en ongeveer 0,3 s om de detector tot rust te laten komen . [ 53 ] Bij 17 kHz duurt de meting nog langer, omdat de testtoon wordt opgenomen in korte bursts van 120 ms (om ongewenste overspraak van de opnamekop naar de afspeelkop te onderdrukken). [ 53 ] De volledige testsequentie duurt volgens Liebert ongeveer 25 s; [ 53 ] onafhankelijke reviewers hebben zelfs lagere tijden van ongeveer 20 s geciteerd. Dit was nog steeds veel langer dan de typische 4 tot 8 seconden die andere auto-kalibratiedecks van dezelfde generatie bereikten, [ 51 ] en bijna de 30 seconden die volgens Liebert "het geduld van de gebruiker op de proef zou stellen". [ e ] Tests en beoordelingen Onafhankelijke metingen Specificaties gepubliceerd door Studer waren zeer conservatief en onthulden niet het ware potentieel van het deck. [ 55 ] Directe vergelijking met Japanse concurrenten was onmogelijk, vooral wat betreft tape transport parameters. De wow en flutter rating van 0,1% van de B215 is bijvoorbeeld een maximale waarde geïnterpreteerd volgens DIN 45507 / IEC 386 , [ 56 ] terwijl de concurrenten doorgaans veel lagere root mean square (RMS) getallen gaven. Onafhankelijke tests uitgevoerd door de pers in de jaren 1980 maten van 0,01% tot 0,042% RMS, en van 0,016% tot 0,07% maximum. [ 20 ] [ 57 ] [ 26 ] [ 36 ] [ f ] Zelfs de hoogste RMS-waarde van 0,042% werd beschouwd als "opmerkelijk laag"; [ 36 ] de B215 overtrof de concurrentie of evenaarde deze met de Nakamichi Dragon. [ 44 ] [ 36 ] [ 28 ] [ 58 ] Craig Stark van Stereo Review gaf toe dat de cijfers zo dicht bij de grenzen van testinstrumenten lagen dat gemeten verschillen tussen de decks in deze klasse waarschijnlijk niet van belang waren. [ 44 ] De absolute snelheid op de lange termijn, typisch voor alle kwartsgestuurde dubbel-capstan-transporten, [ g ] was consistent 0,2–0,3% sneller dan de standaardsnelheid en vrijwel ongevoelig voor schommelingen in de netspanning. [ 20 ] [ 26 ] [ 57 ] [ 28 ] Het dynamische bereik van de B215, begrepen als het verschil tussen het A-gewogen bias-ruisniveau en het maximale uitgangsniveau bij 400 Hz, was vergelijkbaar met dat van de Tandberg 3014, maar consequent slechter dan dat van de Dragon of de Onkyo 2900. Het dynamische bereik in het slechtste geval, gemeten met kwaliteitsband van Type I zonder ruisonderdrukking en spectrale weging, was slechts gelijk aan51 dB vergeleken met de Dragon's54 dB . Beide decks hadden ongeveer dezelfde ruisvloer, bepaald door de bias-ruis (gesis) van de tape in plaats van elektronica; de Revox verloor door lagere maximale uitgangsniveaus. Volgens tests van Audio and Stereo Review bereikte de B215 met Type I- en Type IV-tapes 3% vervorming bij slechts 3–4 dB boven het Dolby-niveau, terwijl de Dragon Type IV-tapes kon opnemen en reproduceren tot wel +10 dB. Howard Roberson van Audio opperde dat de smalle overbelastingsmarge van de Revox een prijs was die betaald werd voor zijn brede frequentierespons. [ 37 ] Nederlands De B215-gebruikershandleiding specificeerde een frequentierespons van 30–18000 Hz (+2/-3 dB) voor Type I-tapes en 30–20000 Hz (+2/-3 dB) voor Type II en IV. [ 56 ] Opnieuw lieten onafhankelijke tests zien dat de prestaties de conservatieve specificaties van Studer ruimschoots overtroffen. De lage frequentierespons, gemeten door het tijdschrift Audio op -20 dB ten opzichte van het Dolby-niveau, strekt zich uit van 9–23100 Hz (± 3 dB) voor Type I- en Type IV-tapes, en tot 24500 Hz (± 3 dB) voor Type II-tape. [ 37 ] [ h ] Op Dolby-niveau, waar de frequentierespons grotendeels wordt beperkt door de tapeverzadiging in plaats van door de speler, mat de Revox 23–14100 Hz voor Type I, 23–16000 Hz voor Type II en 24–17000 Hz voor Type IV. [ 37 ] [ h ] Het gebruik van Dolby C verbreedt de schijnbare bovengrens op Dolby-niveau tot 21–23 kHz. [ 37 ] [ h ] Over het geheel genomen is de Revox-treble-extensie lager dan het record dat is gevestigd door de Nakamichi 1000ZXL (26–28 kHz [ 6 ] ), maar is typisch voor alle vlaggenschipmodellen van midden jaren tachtig. [ 55 ] Het belang van deze parameter werd vaak overdreven door hifi-enthousiastelingen en de op consumenten gerichte pers; professionals vonden het niet belangrijk omdat elk professioneel deck gemakkelijk de 20 kHz-grens overschreed. [ 55 ] De kwaliteit van de kalibratie, een vereiste voor een goede treble-respons, werd als zeer hoog beoordeeld; [ 20 ] [ 44 ] [ 28 ] De B215 wist gemakkelijk de verschillen uit te wissen tussen tapes die zo verschillend waren als BASF CR-M (multilayer chroom, aanbevolen door Studer [ 55 ] [ 44 ] ) en TDK SA (enkellaags ferricobalt). [ 44 ] De lage frequentierespons van banden die zijn opgenomen en afgespeeld op de B215 vertoont een opvallend kamvormig patroon onder de 30 Hz. [ 59 ] [ 26 ] [ 60 ] Deze "kopbobbels", die wijzen op een sterk contoureffect , verschijnen alleen tijdens het opnemen. [ 21 ] [ 61 ] De frequentierespons van de afspeelband, gemeten met testbanden, is exemplarisch vlak, [ 21 ] [ 61 ] vergelijkbaar met die van de Nakamichi Dragon, en merkbaar beter dan die van de Tandberg 3014. [ 61 ] Algemene evaluatie Recensenten tussen 1985 en 1988 gaven de B215 unaniem uitstekende beoordelingen, met name voor de kwaliteit van het bandtransport. Len Feldman van Modern Electronics schreef: "... over het algemeen ... is het werkelijk een Rolls-Royce onder de cassetterecorders. Zijn merk ontloopt prestige. Bovendien is hij gebouwd om lang mee te gaan en om na vele jaren gebruik aan alle gepubliceerde specificaties te blijven voldoen of deze zelfs te overtreffen." [ 28 ] In vergelijkende tests door Stereo Review (Verenigde Staten, 1988) en Audio (West-Duitsland, 1985) werd de B215 gerangschikt als een van de twee beste decks op de markt, de andere was de Nakamichi Dragon. [ 58 ] [ 62 ] De B215 overtrof de Dragon op mechanisch gebied, met een eenvoudiger, robuuster en duurzamer bandtransport. [ 58 ] De B215 verloor van de Dragon op het gebied van dynamisch bereik, subjectief niveau en het spectrum van ruis; andere subjectief gedetecteerde verschillen in sonische handtekeningen waren onbeduidend en konden in het voordeel van beide deelnemers worden geïnterpreteerd. [ 58 ] Op klankgebied overtroffen zowel de B215 als de Dragon de eveneens dure ASC [ b ] en Tandberg decks en de veel goedkopere vlaggenschipmodellen van Harman Kardon , Onkyo en TEAC . [ 58 ] [ 62 ] De Dragon had een voorsprong op de B215 en alle andere concurrenten vanwege het automatische azimutcorrectiesysteem. [ 63 ] De Dragon kon gemakkelijk banden "verteren" die waren opgenomen op andere, vaak verkeerd uitgelijnde, apparatuur. [ 63 ] Zijn zeskanaals, azimut-sensorische afspeelkop bleef een eenhoorn, een ongekend hoogtepunt van cassettetechnologie. Afgezien van een kortstondige poging van Marantz heeft geen enkele concurrent ooit geprobeerd deze te kopiëren. [ 64 ] De productie en aftermarket-service van azimut-sensorkoppen bleken zelfs voor Nakamichi te moeilijk, en in plaats van de Dragon-lijn te ontwikkelen, begon het bedrijf met de productie van unidirectionele automatisch omkerende decks die de cassette fysiek omdraaiden in plaats van het transport om te keren. [ 64 ] Notities a. Voor het dupliceren van grote volumes en goedkope cassettes werden industriële machines gebruikt die 16, 32 of zelfs 64 keer sneller draaiden dan normaal. Duplicatie op hoge snelheid was goedkoop, maar ging ten koste van de geluidskwaliteit. Een realtime duplicator gebruikte normale cassettedecks van hoge kwaliteit die op normale snelheid draaiden. Deze tapes konden zo goed klinken als de cassettetechnologie toeliet, maar realtime duplicatie was duur en alleen geschikt voor kleine oplages. b. ASC (Audio System Components) was een kleine Duitse fabrikant van hifi-apparatuur voor thuisgebruik, beter bekend om hun spoelenrecorders op basis vanBraun-transportbanden. Na de teloorgang van de hifi-industrie schakelde het bedrijf over op industriële dataregistratiediensten en is het anno 2020 nog steeds actief onder de naam ASC Technologies AG. c. Referentie beschrijft de B710 d. Overschakelen van 70 μs naar 120 μs verhoogt het A-gewogen ruisniveau met ongeveer 4 dB en verhoogt het schijnbare verzadigingsniveau van de hoge tonen met dezelfde 4 dB. Het werkelijke verzadigingsniveau, in termen van tapemagnetisatie, blijft ongewijzigd, maar het schijnbare niveau wordt versterkt door een equalizerfilter. e. Liebert schreef dat alles wat langer duurt dan 30 seconden “het geduld van de gebruiker op de proef zal stellen”. [ 53 ] f. In alle gevallen hadden de getallen betrekking op één specifieke steekproef. Deze getallen zijn slechts indicatoren van de prestaties van het deck en gelden niet voor de gehele populatie. g. Fabrikanten maakten nieuwe decks opzettelijk 0,2–0,5% sneller dan de standaard. Naarmate de decks ouder werden, zorgde slijtage van de kaapstander ervoor dat de snelheid geleidelijk terugliep naar de standaardsnelheid. Kleine snelheidsverhogingen werden als veel minder schadelijk beschouwd dan kleine snelheidsverlagingen. h. In alle gevallen gebruikte AudioMagazine de beste, duurste tapeformules - Maxell UD-XLI, TDK HX-S, TDK MA-R. [ 37 ] De Type II TDK HX-S was in feite een tape met metaaldeeltjes, ontworpen om te werken op een Type II bias. Testers selecteerden doelbewust de tapes die de beste resultaten opleverden met de B215, terwijl andere premiumformules niet zo goed presteerden. [ 37 ] Otari NAB Adapters There are several types of Otari NAB adapters, but this article is about this one: These adapters have a rubber belt along the side that is often broken after all thee years. I measured the dimensions of the belt and here it is: width: 7 mm thickness: 1,5 mm folded in half:  ~ 100-105 mm diameter: ~ 64 mm circumference: ~ 200 mm radius: ~ 32 mm Also beware of the 6 (3x2) small pucks that can -and will!- fall out when you remove the rubber belt. Revox NAB Adapters The classic and often most wanted Revox NAB adapters have a rubber O-ring with the following dimensions: diameter: 65 mm width: >3 mm