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.