Another Akai: GX-77

Today I picked up a mint condition Akai GX-77


This photo is from the internet; I will upload a real photo later.

The unit does not work; the two pinch rollers won’t come down all the way and the tape loader roller in the middle is stuck at the top so I will have to fix that. The middle roller is necessary for tape loading and unloading.

auto reverse

This unit is a real beauty. It is an auto-reverse deck, and is capable of playback AND recording in both directions. Therefore it has 6 heads and two capstans. The capstans are always spinning, in opposite directions and only the pinch roller associated with the current playing direction is engaged. The result of this is that switching tape direction takes only 0,4 seconds.

other features and specs

  • It has user adjustable bias through a dial on the front
  • capable of using EE tape (chrome)
  • L+R recording level knobs have a 3rd ‘master’ knob which controls both channels
  • output level is adjustable from the front
  • digital tape counter with optional backup adapter

Here are the full specs:

  • Track system: auto reverse, 4-track, 2-channel, stereo system
  • Heads: 2 x GX record, 2 x GX playback, 2 x erase
  • Motor:
    • 1x FG servo direct-current capstan motor
    • 2x direct-current reel motor
  • Reel size: up to 7 inch reel
  • Tape speeds: 3 3⁄4 7 1⁄2 ips
  • Wow and flutter: 0.03% (7 1⁄2 ips)
  • Fast forward rewinding time: About 80 seconds
  • Frequency response:
    • 25Hz to 33kHz ±3dB (19 cm/s) 
    • 25Hz to 25kHz ±3dB (9.5 cm/s)
  • Signal to Noise Ratio: 63dB
  • Total harmonic distortion: 0.5%
  • Input: 70mV (line), 2mV (DIN)
  • Output: 0.775V (line), 0.3V (DIN)
  • Dimensions: 440 x 244 x 227mm
  • Weight: 17kg
  • Power consumption: 28W

work begins

The first thing I did after opening up the unit was checking the belts. It has three: one capstan belt and two for the spooling motors. The capstan belt was ok, it was still feeling like it should, but it was probably a little stretched because it didn’t feel very tight to me. I ordered a new set which included the 2 spool motor belts for €12,-

Once I had the belts replaced, it still would not engage the middle roller. It is supposed to go up and down.

akai gx-77 with the roller stuck in top position

akai gx-77 with the roller stuck in top position

Searching on the internet I found that there is a large white gear wheel located behind the 2 flywheels which controls the up/down movement of the roller. When I manually engaged this wheel, everything worked. Tape was loading fine. But I had to help it every time. So what could cause this?

old dried out grease

The answer is: old grease. Old grease is grease that, over the course of 35+ years, has started to dry out and instead of lubricating, it starts clogging things. So I had to take the unit further apart to the point where every gear wheel is removed and cleaned.



akai gx-77 plunger arm dried out grease

akai gx-77 plunger arm dried out grease

This plunger arm was very slow returning to it’s default position and probably missed the next turn when the hook had to engage. So I fixed that.

Also the right flywheel (as seen from the back) has a gear on it. This was also very loose on the spindle and could be turned quite easy. I put it in a ultrasonic bath and tried to clean it with IPA. Now it moves a lot rougher.

flywheel with gear

So after almost completely removing all moving parts and cleaning and re-lubing them I carefully put the unit back together to try a cautious test. Here is the result:

As you can see the unit works smoothly now. At the moment the deck is still mostly disassembled but I will put it back together again and then start the mechanical adjustments and followed by the electrical calibration.

Akai gx-77 weer in elkaar

As you can see the beauty is put together again and is recording and playing like new. Very happy with it!

A Quadraphonic 8-track player: National Panasonic RS-845us

The JVC, my first 8-track

jvc ed-1240     IMG_20141125_161052

I possess one JVC 8-track player, the JVC ED-1240, a very nice and featureful deck.

The main reason I am interested into the 8-track world is, of course, the fact that aside from 4 track reel to reel tape, this is the only format that has discrete quadraphonic. I realise that the quality of the sound is not up to par like the Studer, or even a normal tape deck, but it will have to do 🙂

The first time I heard this 8-track deck i was very disappointed with the sound. So I found myself a challenge at hand. I have cleaned it, repaired it, refurbished the motor, changed the belt, demagnetized it, changed all the caps on the power board etc. etc. and eventually it performs quite well.teaser


I cleaned and repadded the 8-track cassettes that I have. I even found it necessary to lube the inside axis a little bit to prevent squeaking and to lower the rumbling and the mechanical noises from the cassettes while playing. The end result is quite pleasing I must say.

But there are still some issues with the player, so if anyone has the schematics, or the service manual, please contact me!

Quadraphonic 8-track

But this post is not about this deck. The JVC is just stereo. This post is about a new one I just bought. A few weeks ago I ran, quite to my surprise, into a quadraphonic 8-track player from National Panasonic, the RS-845us.

Here it can be seen on top of my JVC. At the moment the picture was taken, it was playing a quad tape as you can see by the ‘4 channel’ indicator light. In this mode there are only 2 programs, not 4 as you would find with a stereo tape.

problems ahead

But, alas, this player also came with its problems. I tested it before I bought it, and it was ok as far as I could test it at the time. Coming home, when I could test it for a longer period, I found the same issues I had with the JVC, like irregular tape speed etc. Also the sound was not as good as I was used to from the JVC.

So I did my usual fixup things, like cleaning everything, oiling etc. No good. I quickly found out that the voltage over the motor was dropping several volts at times. I suspected the power circuit board. So i tested the diodes, they were ok. I tested the caps and replaced them all nevertheless, although they were not really out of spec. Unfortunately, that did not help much. New belt. There was some improvement, yes. But still the voltage drop at times, from 12-13V all the way down to 6-7V. The motor would almost stop turning then. And it would squeak a lot.

motor fix

The solution would be to open up the motor and fix it there. That is always a bit tricky but I did it before and I therefore have some experience with the procedure. It went surprisingly well. There was some dust (powder) from the magnets and from carbon brushes. I also scraped clear the spaces between the 3 parts of the rotor (I think it’s called) so there would not be any more shortage. I reassembled a clean motor and lubricated it. When I tested it it it ran very smooth and silent. Cool! The tape speed is also a lot more constant than before. Also the sound seems to have some more punch to it. Maybe it has to do with improved tape-head contact, or with a more stable power supply to the audio board due to the changed caps.

audio fix

But I also have the capacitors ready for a complete overhaul of the audio prints. So somewhere in the next few days I hope I will find time to replace them and see if that will fix the muffled sound. I don’t expect a lot from that action, but hey, that’s what this hobby is all about.


Yesterday I did the recapping of one of the 2 audioprints, i.e. the print for the front channels. This is the result:

When I tested the audio after the process, I found that there was very little, if any at all, change in sound quality. I had made a ‘before’ recording so I could compare the sound.

So I am a little disappointed about that, but I guess the 8-track format was never intended for good audio quality, At least I didn’t break it. 🙂

So while I have all the caps here to replace the rear print also, I will not do that; too much trouble for little or no result…..

Anyway the unit is reassembled now and it playing happily.

spotify on openSUSE

Hello all,

UPDATE 25/8/2018: for tumbleweed users, you can find the latest package HERE, and then you will also need to install a dependency (libgcrypt) that you can get HERE.
After downloading the 2 packages you will need to install them with:
# zypper in ./spotify-client- ./libgcrypt11-1.5.4-2.289.x86_64.rpm

If you’re looking for a binary to install Spotify on your openSUSE installation, you can download a linux client from the spotify site, but that is a .deb file for debian/ubuntu.

I recompiled this client for openSUSE (tested on 13.2). So I build it for you and you can download it here. (binary from march 2015: spotify-client-


Studer A80-R

So, the inevitable has happened.
I have bought a Studer A80-R.

Studer A80

Studer A80


This is a beast. The unit is 70x60x84 cm, and is the size of a washing machine. And it weighs around 100kg. That is even heavier than a washing machine. It has wheels though. So you can roll it around.
This is the studio recorder that the artists from the seventies used to record their material on. It came in several configurations, from 1/8” (cassette tape) to 2” (24 track). Mine is the A80-R (for ‘rundfunk’ i think) 1/4” 2 track, speeds 7½ and 15 IPS (19 & 38 cm/s). Every studio in the world had one, or several. The most prominent artists that used the Studer A80 are Pink Floyd, Alan Parsons, etc.
I came in contact with someone who has access to professional studio equipment and repairs them on a regular basis, often in his spare time. Sometimes studios get rid of these machines that are in the way, and then he takes them in and repairs and refurbishes them.
I have visited him to look at the machine that I would buy and the second time I went there, the machine was all done and I took it home. Which was not a simple task. It fitted the back of my car fortunately.
After I got it home I wheeled it inside, where it would stay in the living room for the time being. It was simply impossible to get it upstairs.

Here is a short clip:


The Studer gave me some challenges. First, the inputs and outputs are the balanced XLR type. I already have adapters to/from RCA which I used for my Revox PR99, but the problem is the line level. My other equipment is home use stuff, so it’s line level is -10dBV. The Studer, being a professional piece of equipment, uses +4dBu. This box fixes the level conversion and the physical connections.

xlr-rca lveveller
Second, the Studer was simply too heavy to carry up the stairs to the first floor where my audio room is. So it sat in the living room, happily enjoying the family life. And, between you and me, it sounds so good in the room.


Unfortunately, after a few weeks, the left motor, the supply motor, was giving problems because the tension was not there in play. Also, rewind was not possible anymore. A search on the net and my supplier both revealed that on the board 1.080.383 there are 2 transistors that control the 2 motors.P1010315

They are BC141-16 with heatsink on them. On my deck the one for the supply (left) motor was broken. I replaced him twice, but that was not the cause of the problem. The problem was elsewhere. The transistor blows as a result of that other problem.
Further investigation revealed that there could be problems with the tension potmeters that control the tape tension (the A80 has a sophisticated tension control system) or with the motor capacitors that could be faulty after 30+ years. I tested the potentiometer and I could not find anything wrong with it. So I removed and tested all the motor caps (9 pcs.) and found they were not entirely up to spec anymore.

A80 rear - motor caps

A80 rear – motor caps

I replaced them all, and installed a new BC141 just tot be sure. And so far, it works flawlessly again. Fingers crossed.

mechanical calibration

So now that all the caps were replaced, i though that the tape tension was a bit off. So i grabbed the service manual and started the mechanical calibration of the deck. This involves setting the (emergency) brakes, the tape path, the capstan pinch roller, and of course the tape tension and edit mode characteristics back to the desired specification. I have bought spring scales just for this! It was fun to do and the end result is here:


So I had a Studer A80 in my living room. Now who can say that? It was always clear that it would have to be moved to the upstairs room eventually. When my brother-in-law heard about my problem, he thought it would be a challenge to get it upstairs. So one day he showed up on my doorstep. Long story short, an hour later it was done. Actually, it took almost an hour to do the preparations like attaching the rope appropriately (and carefully!), and it took just 10 seconds to go from the bottom of the stairs to the top of the stairs! So now it has reached its final destination, my “audio room”.


Being hooked up to some good sounding equipment, my trusty Technics amp and my new KEF Q700 speakers, and using my Philips SACD player as source, I made test recordings and played them back. My tape of choice was BASF 911 and SM900. The results were nothing short of spectacular! The level of OEMPF that his recorder is able to put on tape is astounding! And, those of you who are familiar with analog recording equipment will know that there is always noise (tape noise, vinyl groove noise, FM-noise, cassettes!) when working with these machines. Not so with the Studer! It is so quiet! And that is a piece of equipment that was made around 1970. Incredible.

I am still enjoying this beast. I am tempted to do the technical calibration as well to calibrate it for BASF 911 or 900, but it sounds so good already i’m not sure it would get much better, and there is always the risk of f***ing it up. So for now, i think I’m good.

Latest server uptime record

The last uptime record of one of my linux servers was around 350 days. Today I found another server that has even more uptime: 428 days. Another new record!!

The screendump is as follows:

filezilla:~ # uptime
16:01pm up 428 days 6:48, 1 user, load average: 0.13, 0.10, 0.10


Today I found that the server is still up and going strong!! Updated screendump:

filezilla:~ # uptime
 15:29pm  up 697 days  6:15,  2 users,  load average: 0.30, 0.19, 0.15
filezilla:~ #


I found another one that is still going strong!!

[root@cygnus2 ~]# uptime
 14:14:19 up 833 days,  4:09,  2 users,  load average: 0.02, 0.01, 0.00

A Quadraphonic Akai 1730D-SS

My new addition to the collection is already a few months old, but here is the blogpost anyway.

It is an AKAI 1730D-SS Quadraphonic tape deck that I received from the first owner.

[picture shamelessly stolen from the internet]

When picking it up I tested the deck and only 2 of the 4 channels worked. Only the REAR. Strange. And one of those 2 channels failed intermittently.  When I got home I opened up the deck and had a look at it. I put on one of the many quadraphonic tapes that came with the deck. Quickly I found out that cleaning and fixing the 2ch-4ch switch solved that problem. That was easy.

But the FRONT channels still did not work. At all. No sound, no noise, no click when the deck was powered up, no nothing. I sure hope the playback amp hasn’t died. It appeared there are 4 audioprints in the machine, see picture. At the left of the picture you see the 2 playback prints, at the right the record prints. Each print is stereo. FRONT at the top, REAR at the bottom.

[picture showing the 2 right audio prints removed from their slots]

By turning the pot on the prints I found out wich print was unresponsive (I am going to recalibrate it anyway, so that did not matter). I took it out of its slot for further inspection.

Unfortunately I could not find anything wrong with the print or the components. No burned components, fused caps, burn marks, loose contacts, nothing. I was beginning to feel that I was reaching the end of my knowledge because I have not got expert knowledge of electronics.

When I was going to put the print back into its slot, I noticed something odd about the slot. The slot is a kind of very crude ISA-style slot type, like in the first IBM PC. I saw that the plastic of the slot was broken! That caused the print to not make good contact with the pins in the slot. See the pictures.

When I carefully with my hand pressed the slot so that the print made contact, everything started working! Eureka! ‘There, I found it.’ 

Now how to fix it. Glueing was no option. I soon thought of a tight tie-wrap, that might do the trick. I pulled the tie-wrap as tight as I could. See the pictures.

Then came the next issue. The deck did not want to record at all. I soon found out that the other slots were damaged too (duh). So another set of tie-wraps to the rescue. I put tie-wraps around everything and reconnected it all.

It worked ok, but not reliable. Even when just looking at the recorderprints weird effects on the signal were noticable. First I doubted my tie-wraps, but that solution DID work reliably at the playback prints. Just to be sure I sanded the contacts on the prints and voilá: everything worked flawlessly! So I put the print in and secured them thoroughly. ‘There, I fixed it again’

This is a machine from the early seventies, that has been idle for who knows how long, and I’m surprised at the audio quality.

Now I need to demag it, and calibrate it. Then it will probably sound even better!

Although it sounded good at first hearing, further test revealed there was noise in the left front channel ,even when it was not playing. Same on the right rear.

So I replaced the 2sc458 transistors on all the audio prints. After that, I eagerly turned on the machine.

No signal at all!

Remember that I am only doing this as a hobby, I am not a professional guy and I know very little about electronics.

Searching and searching and searching again I found out that the new transistors I had ordered, had a different pin-out than the ones that came of the print. I had put the new ones in with the same orientation as the old ones, that seemed logical but that was incorrect. :) They simply needed to be turned around, so that was relatively simple. I did not need to cross their legs.

After that it worked again, fortunately! Apparently these guys can withstand some rough handling haha. And the best part is, that the deck is silent again now, the noise is gone. I recalibrated it and it sound great!

A problematic Teac X-2000R

2014-03-31 18.59.39

Recently I obtained, for a fair price, a Teac X-2000R. It is a stereo reverse deck, with 6 heads, which means it will record also in reverse. It has dbx built-in, and it can use (chromium) EE tape. A digital counter in hours, minutes and seconds and bias fine tuning on the front panel is also provided. It has 9,5 and 19 cm/s speeds.

Dual capstan

Another prominent feature that is has, however proved to be a very problematic one. The deck is equipped with 2 capstans. This feature was introduced into the later tape deck models, almost towoards the end of the tapedeck-era, to further improve tape-head contact and wow&flutter. These assumptions are correct, and they work well when the deck is in new condition and everything is well calibrated and up to specifications.

On this deck however, things were not new and not up to specs. The dual capstan design is a challenge in itself, but things are further complicated by the fact that it has to function in reverse as well. On this unit that is accomplished by a belt that ‘travels’ across different parts of the flywheel that varies in diameter.


After the initial cleaning, optical and technical/mechanical, it soon became apparent that the tape handling was not up to par. Sometimes the tape would ‘run away’ from the heads a bit, resulting in loss of audio or worse: tape jam. Things were even worse when playing in reverse. I soon found out (through the service manual) that there were adjustments to be made to the tape tension.

Tape tension

But the increased tape tension was not the solution. When it was ok in forward play, it was bad in reverse. Or vice versa. Or it differed when loading large reels (26 cm) compared to 18 cm reels. Or it was different with different brands of tape. And that wasn’t even reproducible across sessions. And the next day it would be different again.


Of course the first thing I did was to change the belt. I have a blog of that action, but it is in dutch. So here it is, sorry only in dutch:

====== BEGIN OF DUTCH TEXT ======

Nou, de siem-snaar was snel binnen, en vanochtend was het toch regenachtig, dus aan de slag gegaan met het vervangen van de Teac X-2000R snaar.

Ik heb de uitbouw gedaan volgens de foto’s in deze thread, daar heb ik heel veel aan gehad:

Daar wordt behandeld een X-1000R, en die blijkt toch niet helemaal hetzelfde van binnen. Ik kwam meteen al een grote print tegen die in de weg zat, deze is er niet in een X-1000.
Hierdoor kon ik niet bij de bovenste schroeven komen van de plaat waar de capstanmotor op vast zit. De print moest dus los en daarna omhoog gelift worden, er zitten helaas te veel kabels aan vast om hem compleet uit de weg te krijgen.

Na wat kabelbomen losgeknipt te hebben, kon ik de print opbeuren en omhooghouden met een plakbandrol.

Hierna kon ik er wel goed bij.

Nog even de plaat losknippen van de motor zelf:

Er zitten alsnog wat kabels in de weg, maar die zitten gelukkig vast met connectoren. Loshalen die hap dus.

Eindelijk uitgebouwd. De 2 vliegwielen in de achtergrond:

De 2 vliegwielen verwijderen. Goed links en rechts uit elkaar houden.

Overigens viel me meteen op het grote verschil tussen de snaren: de oude is een stuk langer dan de nieuwe. Dus of de oude was wat uitgerekt, ondanks dat het rubber nog vers aanvoelde, of de nieuwe is ietsje te krap. Of allebei.

Toen heb ik alles losgehaald en schoongemaakt en opnieuw gesmeerd: de vliegwielen, de aandrukrollen en het aandruk mechanisme. Oud vet verwijderd, nieuw vet er op. 

Alles zeer grondig schoongemaakt. Vliegwielen er weer op, meteen de washers aan de voorkant weer over de capstans gedaan. Nieuwe snaar er op:

En toen alles in omgekeerde volgorde weer vast. Het was een beetje pielen om de snaar weer over de motor te krijgen, maar het ging uiteindelijk wel. Als laatste de print weer laten zakken en vastgezet.

====== END OF DUTCH TEXT ======

Unfortunately this was not the solution that fixed it completely, although the situation improved a bit. Even increasing the tape tension to incredible heights (or incredible lows) did not fix it. So I went online to find a solution.

Several fora messages suggested that everything in the tape path was relevant to my problem. From tape guides, to the rubber idle rollers, to lubrication of the tension rollers, to the state of the rubber of the pinch rollers. From the tape tension to the smoothness of the tape in question. It seems that everything was related to weather the dual capstan principle would function correctly.
So I soaked the pinch rollers in detergent for one night. The rubber was much softer and grippier after that treatment. Again, a little improvement, but no permanent fix.
I switched the pinch rollers from left to right, to see if that would improve the situation. No way.
I lubricated all the moving parts, I installed the little O-rings that were required for the rollers to function correctly (expensive little buggers!). Still there was no definitive solution that worked all the time.


In April I went to a meeting of fellow tape deck enthusiasts where there was an opportunity to work on decks. I tagged the deck along, and fortunately there was an expert who was willing to take a look at the Teac. Immediately he found one problem: I had put the tape tension way too high. We measured more than 100 gr. when 50 was required. He used a Tentelometer, a very rare instrument which he posesses. It looks like this:

After we adjusted the tension to 50 grams, the tape handling was still not good. In fact, it was worse. Then, the guy helping me thought the problem might be in the capstan motor, of which the carbon brushes would have degraded over the years resulting in less powerful drive. So, on the fly he opened the capstan motor, removed the old brushes and (he had them available) installed new ones.20140412_145008 20140412_144659After this, still no good. But I had new carbon brushes! Jeey!

At the meeting we came to the conclusion that maybe the new belt I had put in was not an original Teac spare part but a fake. So I went to an official Teac repair center and got myself an original Teac approved belt. After I installed that belt, still not any better. Grrrr.

The solution!

Eventually, as a sort of last resort, I took the Service Manual and went through all the mechanical adjustments mentioned there. Some I could do, some I couldn’t. For instance, I haven’t got a spring scale necessary to measure torque. And then, finally, after I adjusted the pinch roller pressure to a much lower value, it suddenly all seemed to come together.
When I adjusted for a very, very low pressure of the pinch rollers on the capstans, even to the extend that I could very easily stop the tape when playing, the tape would indeed run fine along the heads and reverse play was no problem. So I adjusted for a little more pressure but anyway now it works great and I haven’t got any more tape issues.

Great sound

After that, I planned to calibrate the deck. This also proved to be not as easy as I thought. The service manual mentions a lot of steps and I think I did them all 4 or 5 times. The problem was that the record calibration required EE or Chrome tape, which I did not have. Fortunately I could borrow a Maxell XLII tape from a friend.
Bu after I calibrated the deck using the EE tape, it did not sound good. The level was way too low. And when I recorded at a higher level, the amount of distortion was unbearable. Something was not right here. After advice given to me on my favorite forum, I used normal tape to do the calibration. It still wasn’t to my expectation. I’m not sure what fixed it, but I repeated the calibration procedure several times, and after that I found the recording to be very good!

EE (chrome) tape

So the deck was performing as it should, reversing as it should, handling tape as it should and now I was to test it with EE tape and with the dbx noise reduction and dynamic expander on.
The result was, well, as close tot the original sound as you can hope for. The high tones were beautiful, and the sound was quiet as a CD. Out of nowhere the music starts. This is tape technology at it’s finest. I am very happy with my new tape deck.

Installing new Ortofon 2m red cartridge in the Technics SL-1900

Yesterday I received my new cartridge: the Ortofon 2m red. It came with a brush, some screws and a little screwdriver. All in the package for €84,-

2M Red Verso hifisiteI couldn’t wait for a day off to try it so I installed it yesterday evening. I have never before installed a cartridge, and I must admit the thought of doing so was a bit daunting.

I had read a lot about installing and adjusting phono cartridges in the past few weeks so I understood the basics. I had downloaded the Technics protractor from, printed it and checked the scale of the print. But now it was time to put the theory into practice.


My old-style head shell

I soon realized that this new cartridge wouldn’t fit in the headshell I had designated for it. This is an old style Technics head shell with one screw on the top.

Although only one screw is visible in the picture, it has an additional mounting bracket underneath that should fit the 2 screws necessary to mount normal cartridges. But my Ortofon needs to have the heads of the screws on the topside and that is not supported in this headshell.

But fortunately I have two headshells, the other one is the newer type which has the normal two screwholes at the top. Using the screws which were provided in the package I was able to quickly attach the cartridge provisionally to the headshell.


new style headshell

new style headshell

So that was fairly easy. Next was the task of adjusting the ‘contraption’ 😀 I took my protractor and put it on the turntable on top of a record.

I soon learned that when I moved the cartridge all the way to the front of the shell that the needle followed the ‘arc’ on the protractor perfectly. Yes!


using the protractor

But when I tested the alignment of the cartridge on the two gridline patterns on the protractor, I found that it was not perfect in line. So I adjusted it very slightly to the point that it was in line on both patterns and then secured the screws. Pfew! Job done!




Yes – 90125


Then came the testing. I must admit I was a little but afraid, or better anxious. I tried it out with a record from Yes – 90125.

I put the needle down very very carefully.

I put on my headphones.

But as soon as the first tones from the song (Owner Of A Lonely Heart) were played, I relaxed. It sounded very very good!


The Ortofon happily playing in my sl-1900

There is a lot of definition in the sound. There is also a lot of ‘punch’, which I like. HF tones are also ok. Bass is tight and well defined. Overall, I have never ever heard a record sound so clear. True, in the past I have not had good quality turntables. In fact, they were rubbish. But I never thought a record could sound like this. It is so close to a CD. I’m also very glad that I treated my records carefully in the past, I didn’t play them a lot (I immediately recorded them onto tape) so that I now have old, but ‘like new’ records that sound wonderful!

I continued to listen to albums from ELO, Marillion, Tchaikovsky and 12-inch’s from Chaka Khan, Unique (What I Got IS What You Need). Those were the first records I found for grabs. It was a good experience. I am pleased. In the coming evenings I will listen to some other albums.

I was surprised how quickly and how easily an inexperienced person like myself could do this task. It took me a little over an hour including the adjustments. I can recommend it to everyone.

Coming up next: cleaning the records with a LP cleaner

New arrival: Technics SL-1900 turntable

This week I picked up a Technics SL-1900 turntable


Technics SL-1900 (image borrowed from internet)

I was actually looking for a more high end model, like the Technics SL-1600Mk2, SL-1700Mk2, 1800Mk2 or even an SL-5300. But, those are hard to find, and when found, are very expensive and could cost more than €200,-. I found a very inexpensive SL-1900. It still had the original Technics 270 cartridge installed. And it came with an additional 270 cartridge without a needle. So I thought ‘oh, what the heck’, and I went to get it.

I was not disappointed. Not at all. In fact, I was very impressed. For the last years I have used a Dual cs-607, so that was my reference. And although the Dual has more definition, this one is more agreeable to listen to because….well, it has less definition. It doesn’t reveal all the noises and scratches and clicks and pops from the record so much as the Dual does. Compared to the Dual it lacks highs though.


Please read the next post on how I installed an Ortofon Red cartridge in this turntable.

Some information from internet:


The Technics SL-1900 is a 2-speed, direct-drive turntable with fully automatic single disc playback. A one-chip IC, incorporating 321 elements, controls motor speed for superb accuracy with servo control. The tonearm mechanism gives convenient automatic set-down, lift-off and stop. Memo-repeat control permits up to six repeated plays of the record, or continuous play. The heavy monolithic bas and isolator system protects against external vibrations. The SL-1900 comes complete with an EPC-270C-II moving magnet phono cartridge.

Some specs:

  • Brand: Technics
  • Model: SL-1900
  • Manufacturing year: 1977
  • Made in: Japan
  • Colour: Braun
  • Power: 4,5 Watt
  • Dimensions: 137 x 430 x 334mm
  • Weight: 7,2 kg
  • Original price ca.: $400,-
  • Direct Drive
  • Fully automatic operation
  • Platter: 310mm aluminium diecast
  • Speeds: 33 and 45rpm
  • Wow and flutter: 0.03% WRMS
  • Rumble: -73dB
  • Tonearm: universal, static balanced
  • Effective length: 230mm
  • Overhang: 15mm

und auf Deutsch:

Technische Daten

  • Antrieb: Direktantrieb
  • Motor: Gegenelektromotorische-Kraftfrequenz-Generator Servo Gleichstrommotor
  • Drehzahl: 33 1/3 und 45 U/min
  • Gleichlaufschwankungen: 0,03% WRMS (JIS C5521), ±0,042% bewertet Null-zu-Spitze (DIN 45507)
  • Rumpelgeräuschabstand:
    • DIN 45539A: 50 dB
    • DIN 45539B: 73 dB
  • Plattenteller: Aluminium-Spritzguss, 310 mm
  • Betriebsart: Automatisch oder manuell
  • Pitch: ±5%
  • Tonarm: Rohrarm, statisch balanciert
    • Nadelauflage: 0 – 3 g
    • effektive Achslänge: 230 mm
    • Überhang: 15 mm
    • Kröpfungswinkel: 21,5°
    • Reibung: 7mg (horizontal und vertikal)
    • Spurfehlwinkel: Innerhalb + 3 (145mm vom Mittelpunkt), + 1 (55mm von Mittelpunkt)
    • Gewichtsbereich für Tonabnehmer: 5,5 – 9,5 g
    • Gewicht des Tonarmkopfes: 9,5 g
  • Tonabnehmer: Technics EPC-270 C-II (MM)

Besondere Ausstattungen

  • Aufsetztpunkt: Einstellbar für 12″,10″ und 7″ Schallplatten
  • Memo-Repeat: wiederholtes Abspielen von ein- bis sechsmal, oder dauernd wiederholendes Abspielen einstellbar
  • Schwergewichts-design: Schweres Polymer-Unterchassis auf Viscoelastisch gedämpften Stahlfedern
  • Motor-Rotor ist direkt mit dem Plattenteller verbunden (war damals von Technics entwickelt worden)
  • Elektronisch gesteuert mit damals revolutionärem One-Chip-IC AN 630
  • hochempfindlicher Tonarm mit Kardan-Aufhängung in Präzisionszapfenlagern. Damals ebenso aussergewöhnlich.
  • Viscogedämpfte Tonarmsteuerung und Anti-skating – damals ein Novum ebenso wie die dicken, kapazitätsarmen Phonokabel.

Information about the cartidge:


  • Hersteller: Technics
  • Modell: EPC-270C-II
  • Baujahre: zum 1976
  • Hergestellt in:
  • Farbe:
  • Gewicht: 6,0 g
  • Neupreis ca.:

Technische Daten

  • Prinzip: MM
  • Frequenzgang: 20 – 15.000 Hz (±2 dB)
  • Kanaltrennung:
  • Kanalbalance: 2 dB (1 kHz)
  • Übersprechdämpfung: 25 dB (1 kHz), 20 dB (10 kHz)
  • Ausgansspannung:
    • 1 kHz, Höchstamplitude: 3,2 mV
    • DIN 45500: 6,4 mV
  • Abschlusswiderstand: 47 kOhm – 100 kOhm
  • Induktion:
  • Nadeltyp: Diamant elliptisch
  • Empfohlene Auflagekraft: 1,75 ±0,25 g
  • Nadelnachgiebigkeit: 12x 10^-6 cm/dyn

Checking out dbx encoded discs (vinyl)

The other day I received two dbx encoded 7″ singles, demonstration discs by Technics. These are supposed to have superior dynamic range and almost no noise/hiss/rumble whatsoever.




First some background:

dbx was also used on vinyl records, from 1973 until around 1982, and over 1100 albums were released with dbx encoding, which were known as dbx discs. When employed on LPs, the dbx Type-II system reduced the audibility of dust and scratches, reducing them to tiny pops and clicks (if they were audible at all) and also completely eliminated record surface noise. dbx encoded LPs had, in theory, a dynamic range of up to 120db.[3] In addition, dbx LPs were produced from only the original master tapes, with no copies being used, and pressed only on heavy, virgin vinyl. Most were released in limited quantities with premium pricing. [wikipedia][

Well, the accompanying sheet suggest that you hook your equipment up to a dbx capable (cassette) deck, but I didn’t. Instead, I connected my dbx model 150 unit. Better!

On all 4 sides was music, mostly jazz-like. On side A of the first disc was an impressive dynamic piece with flute and big drums. I was very surprised when the drums reached full power! And they go very loud! It is an extremely dynamic experience. Even on headphones.

Clicks and pops  and other vinyl noise are so unnoticeable, the whole listening experience is very, very enjoyable. Even the dropping of the needle was hardly audible. Now, I need to find me some other dbx encoded discs!

edit: while writing this down, I’m thinking about what would happen if I record this on a tapedeck with dbx encoding.
Or better: skip the decode and encode step, and record the disc as-it-is on tape, and the play it back through my dbx unit….interesting experiment. I should try that some time.



Solving famous cracking sound problem: replacing all transistors in mainboard Philips N4520

A few months after my purchase of the Philips N4520 tapedeck, it developed a nasty fault: during playback there would be cracking sounds coming through the music, or even when not playing at all. Also when touching the knobs, there would be pops and clicks.

An intensive internet search revealed that there were more decks affected with the same symptom. Fortunately, a remedy was also given: replace the transistors on the main circuit board with new ones. Gulp. All 19 of them.

I have some experience with soldering, but this was a completely new level for me. I happen to be in possession of a very good soldering station with temperature control, and I have used litz wire once or twice, to remove solder of the component you want to remove.


So, I ordered the necessary components on-line:

 7x BF245A : TS2 TS5/TS105 TS4/TS104 TS3/TS103
 1x BC547 : TS11
 4x BC548 : TS8 / TS108 TS9 / TS109
 2x BC549 : TS1/101
 1x BC557 : TS10
 2x BC546A : TS6/106
 2x BC556A : TS7/107
My new friends

Total number of transistors: 19 pcs.
Total cost: around € 10,- excl. transport.

Then, the scary part started.

Taking apart the biggest monster in taperecorders known to mankind.


Well, almost. And, as I found out, the bottom part slides out fairly easy to the front. And it is connected to the rest of the machine with connectors. So in the end you have the bottom part which contains the ‘mainboard’ as I call it as a separate unit on your workbench.

Locating the components on the printboard was difficult, but doable. Then soldering started. Using the litze wire to remove the solder from the board, I was able to remove the components.

Don’t shake!
My old friends. Well, not my friends anymore!

Working methodically through all components, I replaced all 19 of them. Double-checked the joints for good contact. Cut away the excess pins. And I was left with this:Then it was time to test. To do that, the mainboard had to be reinserted into the recorder and reconnected.

It worked! Yay! I now have a N4520 that plays back and records beautifully! It took about an afternoon’s work and about ten euro’s, but Then you have successfully restored a very very nice machine.

The glorious Philips N4520 in action 

See a video of this beast in action on my YouTube channel:

Update 20210116: I also made a handy ‘layout quick reference guide’ for the audio main board (also better known as Panel 1) which comes in handy when you are troubleshooting or calibrating the deck.

Picture is below, you can download it here in PDF format.

20220415: Another updated version is here in PDF.
And here is a diagram of the faceplate. Also handy!

BETTER STLL: visit the Quick Reference Guide section of my website, for new and updated QRGs all the time.

Servicing the new ReVox PR99 with new VU lamps and roller bearing

Hello all,

Today I have been busy servicing my new ReVox PR99. This deck is built like a tank (to use an too often heard metaphor regarding tape decks) and it is working well. It is a 2 track deck which is designed for heavy use, like in studios and broadcast facilities. It is world famous for that.

But when I received it – actually I fetched it from way across Holland – I immediately noticed three small things wrong with it:

  • the VU meter lights were not working
  • the left tape guide roller bearing was making noise
  • and the infrared tape sensor incorrectly identified tape as being leader tape and switches off. This happens with some tapes that are apparently too thin 🙂

So I ordered and received 2 spare bulbs (from a webshop) and one new roller bearing (from ebay Germany) and opened the unit up.


rear view



P1020841 P1020842 P1020843 P1020844 P1020845 P1020846 P1020847 P1020848 P1020849 P1020850



without case







First I removed the siderails and the frontplate knobs




Then I removed the face plate all together.






Get the meters and the controls out





Remove old and insert new bulb





Testing….yes! Part 1 is done!





Remove the bits around the heads.
Also a good time to do some cleaning.





Remove the old roller bearing





And put the new one in place. Part 2 done!






Also put the unit on 240 Volts






This is the test point where the tape sensor should be measured





And this is the potentiometer that should be adjusted.






All done! There is light in the dark!

New arrivals: Philips N4520 & Teac X-300

New decks

All of a sudden the tape recorders are pouring in. At almost the same time I got hold of a Teac X-300, a small 18 cm reel deck from one of the last series made by Teac around 1987, and a Philips N4520 from around 1978, which is THE kick-ass deck to have from Philips if you want to do serious business. It is really monstrous.

Philips N4520

The Philips N4520 has some unique features not found on other decks or only on very expensive studio decks, like

  • bias adjustable from the front panel
  • wind speed is adjustable on the front panel
  • electronic tape counter in 1/10 meters
  • Selectable equalization (at 38 cm/s) after NAB or IEC
  • cue buttons for fast winding&play without using the stop button
  • peak hold (yes, on analog VU meters!!) with peak leds as well
  • mini input mixing console with master fader
  • constant tape tension, so no reel size switch needed. Even when winding!


After listening to my first test recording on the 4520 with new and fresh SM911 tape through my Sennheiser HD-600 I was really blown away by the depth of the sound! It appears the 4520 has a build-in headphone amplifier that is very very good! It adds a lot of OEMPF to the sound. I did not know a good phone-amp was that that important to the overall sound. Also the sound quality on the line level is astonishing. The only difference when comparing the recording to the original is the tape noise, which is by the way very low. But that can be solved by using my newly bought (I haven’t told you yet. Sorry about that) DBX units.


Anyway, this Philips is the top of the line from all Philips tape decks. Among audio enthusiasts it is a very sought after model. It has some weaknesses, but mine has been under repair and is now ready for use. Also some modifications only found on later produced machines have been done. Sonically, I think it is my best sounding machine. But a comparison between my Tascam 34B and this baby will probably happen in the not so near future.

Teac X-300

Not forgetting the other new deck, the Teac X-300. It is a compact built unit, as it only carries 18 cm reels. It is one of the last series built by Teac, and it shows. It has a plastic look and feel, however, when you operate it it feels very robust. It is capable of handling the new EE tapes (or chrome) with superior audio characteristics which unfortunately have not been very successful when they came out in the mid 80-s. I do not own such a tape, so I can not test it.

This unit came very cheap, only €50. It is in e very new state. I don’t think it has many hours on it. Everything on the deck feels new and fresh, like the brakes and the controls etc. When comparing the sound quality using SM911 with the new N4520 it came sooo close, I was really surprised. This is definitely a keeper, if I can live with the small reel limitation.

Tomorrow I will add some photos to this article

Some simple math…..proving 0,999999999 equals 1

I am going to prove to you, using standard algebra, that

0,99999999999….. equals 1.

Now I know that if you have even a basic understanding of maths you say: ‘I know for sure that’s not true’, but I will show you otherwise.

So here is the breakdown:

    1. let’s start by substituting 0,99999999999….. with the letter a, so

a = 0,99999999999….. 

That is easy huh?

 2. now say 10 times a would mean

10a = 9,99999999999…..

that is still right, right? I don’t believe that there is any need for discussion here.

3. if we substract a from that, of course you have to do that on both sides of the equal sign, we get:

10a – a = 9,99999999999…..  – a

still a correct formula.

4. 10a – a is of course 9a, so:

9a = 9,99999999999…..  – a

 5. but since a = 0,99999999999 the right side of the formula could be written as 9

9a = 9

6. and that means that a must be 1

a = 1

7. combining step 1 and step 6 I have proven to you that

0,9999999999….. = 1

The surprising Teac A-3340S

From a friend of mine I recently received a Teac A-3340S in good condition. Here is a picture of it:


Teac A-3340S in good condition

My friend had just acquired it and asked me to take a look at the levels and to do an overall adjustment of the deck for him. This is I believe the first 4-track quadro deck by Teac, introduced in 1973. The deck is very very heavy and very very well built. This particular deck is also very well kept, there are no signs of usage and it looks like it has just come out of the shop. Remarkable as this deck was in production from 1973 until 1978.

IMG_20130802_090704 IMG_20130802_090722












After I serviced it, it sounded wonderful! It was a pity I had to return it to my friend, but well, it was his deck.

I found a fine new tapedeck: Philips N7300

A few weeks ago I found an interesting tape deck online. It was a deck from Philips. It was close by so I immediately e-mailed the seller and after some conversation I fetched it with the car. It was a good price. Although Philips are not well known for the quality of their consumer decks (whereas their professional decks ARE good) I was interested because this was their last model that they made before production stopped because of the changed market conditions, everyone wanted a cassettedeck.

I believe it was produced in 1983, so it is fairly modern in its technique. It has controlled tape tension amongst other things.3 speed: 4,75 & 9,5 & 19 cm/s. It takes the BIG reels. Pitch control.

P1020407The problem with this deck is that it is entirely made of plastic. And I mean not just the front and the chassis, but even the cog wheels and everything inside. The result is that it is very light, especially compared to some of my Teacs and Tascams. So far nothing has broken. This would be a big problem as it seems to happen a lot and the plastic parts are, well, impossible to find or replace. Fingers crossed! The only thing that didn’t work was the on/off switch, but I managed to secure it in the ‘on’ position and I just unplug the unit to switch it off. Works for me!

Philips N7300 with tone generator

Philips N7300 with tone generator

So, after the holidays I managed to find time to do my adjusting and tuning. The Service Manual was quickly found on the net and then I started work. Unfortunately the SM is, well somewhat vague in some parts. It was quite the struggle I must confess. I could put my new oscilloscope (also from Philips BTW!) to good use. In the process I found out I still need to learn to use the scope better. But I managed.

I just finished the work recently and did some tests with test signals and some music. I must say that the results are very, very good. Did I mention that this is a very good sounding deck? Switching between source and tape it is very hard to hear any difference at all. I use new BASF LPR35 tape. Especially at the middle speed of 9,5 cm/s it performs remarkably, delivering very close to the same audio quality as at the highest speed. I was really surprised.

Even at the slow speed, at 4,75 cm/s it was very acceptable. One could use that for parties where the music will not be played loud, for background use. A full reel 26 cm with 35 micrometer tape has 1100 meters on it, giving a playing time of almost 6 1/2 hours! Using the thinner tripleplay tape of 25 micrometer gives even longer playing time of 8 1/2 hours.

Overall I am very pleased with it. This will probably become my main deck for 4 track stereo recordings, where the TASCAM 34B is the main deck for 4 track quad recording.


English text follows below:

Hier een filmpje van onze huiskoolmezen. Eigenlijk zijn het geen echte koolmezen, maar een andere mezensoort. Welke dat is, dat weten we niet 🙁 Ze hebben een kuifje….

Sinds enkele weken hebben we jonkies in ons vogelhuisje. Op dit moment staan ze op het punt van uitvliegen. Ik heb hiervan een filmpje:

English text:

This is a clip of our domestic tomtits. They’ve got a tuft….

For some weeks now they are in our birdhouse. At the moment they are on the verge of fledging. I have got a clip of this:


Another server uptime record!!

The last uptime record of one of my servers was around 300 days. Today I found that the server still hasn’t rebooted and that has even more uptime: 353 days. Another new record!!

The screendump is as follows:

fotoserver:~ # uptime
 08:35am up 353 days 16:55, 1 user, load average: 0.14, 0.05, 0.06

New project: Sony TC-378

Sony TC-378

Sony TC-378

This is my new project, the Sony TC-378. This is the ’tilted’ tape recorder, the front plate is hanging back, although is is not very visible in the pictures. The message given to me when I got it was that it worked ok and the pause button was missing.

Well that is both true. It plays nice and the pause button is indeed missing. It is possible to use the pause function however. This unit has the nice feature of a pinch roller that is moving out of the way when the tape is not playing. That is very clever because the tape path is clear when loading the tape. No fiddling the tape in between the capstan and the pinch roller. How this construction will last over the years is of course another question. And pinch roller pressure is of course also an issue.

TC-378 open

TC-378 expanded

The only thing that is in need of fixing at the moment is the supply reel. When rewinding, it makes a screaming sound that is impossible to bear. I guess there is something wrong with the bearings. I will have to look into that.

Finally calibrated my Tascam 34B

Teac A-3440

The ‘older’ Teac A-3440


This past week I finally got round to working with my recently bought Tascam 34B. Ever since I got it a few months ago, I haven’t been satisfied with the sound at all. And surely not for this kind of machine. The tape transports are ok, very good exactly. The overall look and feel is excellent, working with it is an absolute joy.

But the sound was not ok. The sound was a little bit muffled, and some highs were absent. My older Teac A-3440 sounds a lot better. But of course, that deck I have already tackled. Using some other decks I finetuned my skills over the last few months, and now I felt the time was right to take on the big mighty TASCAM 34B.

Fortunately I had the service manual (recently purchased on the internet for a few euros, it was not freely available) so I used that as a guide. Other tools I used were my trusty calibration tape, a blank tape of LPR35, my old Philips scope (which will be replaced by a better scope, more on that later), my Philips analogue voltmeter PM2505, and software called Visual Analyser (for spectrum).

On the workbench, my 34B looked like this:


TASCAM 34B with face plate removed


TASCAM 34B bottom view. Notice the adjustment ‘knobs’

So, after a lot of fiddling with the potentiometers, measuring levels, changing tapes, etc. etc. I was done. So I eagerly recorded my first music onto it, played it back and …………..


The sound was really, really great! I used CD recordings of Dire Straits, Donald Fagen, and 4-track surround (quad) music of Pink Floyd, The Doors, Doobie Brothers and Queen – Bohemian Rhapsody to test, and I could hardly, if at all, distinguish between de CD and the tape.

This is truly amazing. I did not know a tape recorder could reproduce sound this good. As you can notice, I’m happy with the modifications I have done.
I don’t think this baby will go anywhere anytime soon, it will stay with me.
tascam 34b small

Server uptime record

Today I noticed a new uptime record on one of my servers. The screenshot follows:

Have a lot of fun...
fotoserver:~ # uptime
 09:17am up 301 days 17:39, 1 user, load average: 0.00, 0.01, 0.05
fotoserver:~ #

301 days, a new record for a server.

A New Finding

I recently found an old, but rather unused Akai 4000DS Mark 2.

Akai 4000DS Mk II

My Akai 4000DS Mk II, head cover removed, here in play mode

I got it for 25 euros from a first owner, who clearly was careful with his equipment. The only thing it suffered from, was a lack of maintenance and the fact that it had been sitting idle for a long time. I got it with one old and worn tape. This tape contains mostly 70-s music, like Abba and Steelers Wheel.

I really wanted to start working on Akai decks, because here in Holland, there are a lot of Akai reel-to-reel decks sold in the past decades. And I mean A LOT. I guess that for every 2 decks, one is an Akai. You see them everywhere. So, while it is not my favourite brand (that would be Teac/Tascam) in the future I will encounter them a lot and this will be a learning experience, and I wanted to get some hands-on.
This deck is a budget deck from Akai, so I can really try things out without the risk of messing up a more expensive deck. I will try that later on :). I already downloaded the servicemanual for this device, so that will be my guide during the repair and calibration process. My goal will be to fix this deck up so that it will perform like new, functioning to the best of it’s abilities.

The quality is well, let’s say, not entirely up to standard. Although the unit is fairly clean overall, the heads were covered in a lot of dirt. Unfortunately I haven’t got a picture of that. I was wondering at that moment if I would ever get them clean again, or whether it may be corrosion and thus irreparable  besides fitting in new heads.
I cleaned the heads and the entire tapepath with 96% denaturated alcohol. Then I tried to make a recording. That worked, and listening to it using ‘source – tape’ switch it sounded remarkably good! This was promising. I noticed that the odd ‘equalizer 3 3/4 – 7 1/2’ switch really does make a difference: when set on 3 3/4 (inch/sec) the audio contains too much high frequencies.
Another fun fact about this deck is that there is no speed switch: to make the deck run at the higher 7,5ips/19cm speed, you have to use an add-on to the capstan, that is stored on a storage post on the faceplate above the heads. Here’s a picture to make it clearer:

capstan with on the left above the head box the additional piece that goes over it.

When applied, the capstan is thicker and the tape runs at the higher speed. The capstan motor never changes speed!

Next, set the deck to 240V, the new line voltage here. As the deck only has one motor for all tape transports like play, fast forward and rewind, there’s a lot of mechanics going on inside. Greased that all up. Demagnitised the heads and tape path. Cleaned that with IPA too, and the rubbers also. The deck runs smoothly now.
A test recording confirms the new found audio quality. Then, loaded a calibration tape and adjusted the playback head’s azimuth with the 1 & 10 KHz tone using a scope. Here is a picture of what that looks like:

Akai 4000DS 10 KHz azimuth

Akai 4000DS 10 KHz azimuth

After that, made a picture of my trusty scope while playing back an 18 KHz tone from the calibration tape:

18 KHz toon vanaf referentieband op Akai 4000DS

18 KHz tone refererence tape Akai 4000DS

That’s not wrong at all. So far, so good. Next up is the further calibration of the electronics on this deck and calibrate it to use the newer 320 nWb/m tapes, but the service manual is a bit, well, let’s say, unclear about some things.


Well, I have gone further with this deck. I could not figure out some parts of the Service Manual (I think it may be a bit incomplete or in error, but anyway who am I) so I finished it of with adjusting it as best as I could. And I must say, it sounds far better then I expected from such a low-end deck. I am really, really surprised!
I hope I can sell this deck to someone who will appreciate it and shows some love for it.

Another update:

The deck has been sold, at a good price I may add, to a customer who is going to use it in a reproduction studio where mainly videotape is being digitized. They needed a good sounding compact deck for an upcoming job digitizing reel to reel tapes. Well, they got a good one. I’m happy the deck is being put to good use and it will be working in a production environment. 😀 🙂