Vintage Audio
this section covers some restoration work that I did on my vintage HI-FI gear
Article #1 | 08:24 PM Sunday 03/01/2016

Introduction: Vintage Audio Restorations

This board presents technical information regarding the vintage gear that I restore from time to time.
Just to mention that I work slowly and most of these restorations span over many weeks or even months. Updates will be infrequent.

If you would like to view my work on audio amplifiers, please follow the links below.

AKAI Electric Company Ltd. SANSUI Electric Company Ltd. PIONEER Electric Company Ltd. Miscellaneous
AKAI AA-5210 #1
AKAI AA-5210 #2
SANSUI AU-6500 #1
SANSUI AU-6500 #2
SANSUI AU-8500 #1
IEI A-350

If you are into tape decks then check my work in this field.

AKAI Electric Company Ltd. SANSUI Electric Company Ltd. SONY Corporation STUDER / REVOX
REVOX B215 #1

And if you want to see restorations of other audio devices please check the following articles.

ACCUPHASE Laboratory, Inc. SANSUI Electric Company Ltd. DENON SANSUI Electric Company Ltd.

Tip: To return to this page, always click the title of this site.

Legal: You are not allowed to use any of the images presented in this web site without my written consent. Also, I would not be happy if I would see my images on auction sites backing-up restorations of sellable HI-FI gear. However you are allowed to use the images on repair topics in technical forums provided that you credit me as the source of the images and original work.

Article #2 | 11:12 AM Sunday 17/02/2019

About Vintage Audio Equipment

Driven by a growing frustration regarding the maintenance of various cassette decks, I have decided to write an about... section for each class of vintage HI-FI gear that I have an interest into. While it is true that, in pictures, you can see these marvels and make yourself a surreal idea about them, you should also know that all this equipment is very hard to maintain. If you want factory-like performance, that is. Otherwise, they will work anyway, albeit in a degraded manner.

About Preamplifier and Amplifiers

Most vintage preamplifier and power amplifier units are still working by now. Even if not within their full mental faculties. But you can still enjoy their vintage sound. However I would say that almost all of them have drifted working parameters and should be restored.

Thankfully, restoring such units is fairly simple because there is no precision mechanism to align and tweak. I would say fairly simple but people perceive simplicity vastly different. What I consider simple could be complicated for somebody else and recto-verso.

Normally, restoring signal amplification devices is limited to replacing electrolytic capacitors, possibly small-signal transistors and diodes, but rarely power transistors. In some isolated cases, you need to perform debugging and reverse engineering of several unobtainable circuit sections. Sometimes, oscillation tracking and damping is also carried. Finally, idle current adjustment and DC offset output -- if available -- are the last steps before declaring the restoration over. It is funny that up until recently (early-2020) I was still convinced that small-signal (and not only) transistors actually contribute to the sonic signature of the unit they're part of. However, I have changed my mind after lots of replacements that ended only with improvements.

Of course, cleaning switches and mechanical controls is a tedious operation which in some cases cannot be overruled. Thus, one must disassemble fragile mechanical components for thorough cleaning. I am absolutely against cleanup sprays and chemical substances.

Sure, once restored, preamplifier and power amplifier units are rewarding and worth keeping around. In most cases, they will not directly compare with similar new HI-FI gear -- think McIntosh or Accuphase; forget the sinister supermarket audio equipment. But these vintage units have their charm. They are still worthy of your audio rack.

About Cassette and RTR Decks

These units contain two main sections inside that are indispensable for a quality sound recording and reproduction. There is the high precision mechanism and the electronic circuits. Both sections need to be fully operational in order to deliver the expected specifications. Cassette deck peak was in 1988-1993. They were overruled with the introduction of the digital audio tape (DAT) and the compact disc (CD). Normally, after all these years either the mechanism or the electronics are suffering. Or both at the same time. And what do you know: both require the right tools for alignment. If you don't have them, decks can and will sound like crap.

So where does my frustration come from?

Let me explain. Over the time, I owned around fifty different cassette decks, and I parted ways with almost all of them. The truth is that I had these over the time they were pretty much standard audio equipment. This means I have not experienced problems with most of them. I finally settled down to only a few cassette decks and just one reel to reel tape deck. I believe these are going to be my last decks. However, all of them had issues, more or less severe. Nothing that cannot be corrected, though. On the other hand, scarcity of precision mechanical parts, can quickly render these machines as inoperable; expensive paperweights, in other words.

Let's take the machines one by one for a brief enumeration of some initial issues.

  1. AKAI GXC-760D: Main transmission belt, worn out pinch rollers, dry capstan bearings, severe wow & flutter, dried out or cooked capacitors, burnt out light bulbs, direct-drive reel motor faults.
  2. SONY TC-K850ES: Main transmission belt, mode belt, worn out pinch rollers (especially supply side) and leaky capstan motor controller filtering capacitors.
  3. SONY TC-K555ESA: Main transmission belt, worn out supply side pinch roller, leaky capstan motor controller filtering capacitors, misaligned tape path -- this is again, bad.
  4. REVOX B215: Dry capstan bearings, worn out pinch rollers, dried out or shorted capacitors, broken IR tape detector.
  5. STUDER B67 MKII: Dried out or shorted capacitors, worn out pinch roller, burnt bulbs, several other minor defects on various printed circuit boards.

Whenever I wanted to listen to a tape, I got angry, because neither of these decks was in a 100 % functional state. You can't even imagine the frustration arising from loading a tape and after 10 minutes or so, the machine started meowing with loads of wow & flutter. Of course, there was nothing that I could not fix. But the amount of time involved in these repairs is, simply, outrageous. I have other daytime duties as well. Often I find myself running out of time and the thought of maintaining these decks, just for listening to old mixtapes, is slowly eating me from inside. I often think about digitizing all these old recording and sell all the decks. But then I remember the good old days when I spent my time sorting music and recording it on cassettes. And I almost forgot: a tape recorded on one deck, almost always doesn't sound the same on another deck. And I am not referring to sound qualities but alignment. Almost all of my decks have factory aligned heads. So head wear should be taken into consideration. Once heads are off course, there is almost nothing that can be done to restore them. New heads are practically unobtainable. Sure, GX heads are slow wearing. But they already have quite a lot of running hours, by now.

This leads me to speak about cassettes. I had a lot of them over the time and now I have less than one hundred. Mostly CrO2 tape formulation. Music is mainly Italo Disco ('80s) and Eurodance ('90s) but also some other genres. I don't want to destroy these old tapes with misaligned machines. Disaster waiting to happen: tape chewing is a real issue and the deck is stalking me. When I'm not aware, it will happily eat the tape, ruining my precious audio memories.

Sure, once restored and properly aligned, decks are exceptionally rewarding. Seeing the precision mechanism at work, combined with hearing the exceptional -- for the late '80s that is -- electronic circuits, is a mesmerizing experience. As long as it lasts; if it lasts. These are old machines and issues are waiting for around the corner. Compare them with old cars, if you want. Would you risk driving a '60s car on the highway, for a couple of hours, at a steady 130 km/h? Even if properly restored, I probably wouldn't. I reckon maintaining these decks is already a dying art.

So there you go. Keep these lines in mind, should you ever want to buy a cassette deck.

About Tuners

HI-FI radio tuners are very nice devices, as long as they work, and there is a quality radio station around you. If they are misaligned, realigning them is difficult, even with adequate test equipment. And if there is no quality radio station around, there is absolutely no point in owning a radio tuner.

Possible easily fixable defects include, but are not limited to, burnt scale bulbs, crack and pop noises from bad transistors, and faded flat sound due to bad capacitors. These issues are easy to fix.

If I were to choose a radio tuner, I would search for a 4-gang variable capacitor analog tuner. I have had top of the line quartz locked digital tuners from AKAI and Sony; while they were incredibly well built machines, oozing technological advancements, they sounded different than analog ones. Not bad, but different.

I am lucky that I can listen to at least two nice FM stations and at least one AM station. Emission quality is not that good but the musical program is very nice. News programs are of good quality. But when these stations will cease emission, I will retire the tuners forever. Unfortunately this will happen, some day.

About Turntables

This is a different category of audio devices. I am not very experienced in this domain and I have not serviced more than three turntables in my entire life. Sure, I owned various models in the past, but I ended up parting with all of them. Now I only have a single turntable and I consider that it fulfills my needs with minimal maintenance. It is a very old model that is still working well, give or take. Before I restored it, once it heated up, speed drifted upwards a bit. I used to correct this via the RPM control knob. In the meantime, I fixed it.

As a general advice for the casual turntable buyer: avoid junk. Better wait and raise funds to get a good turntable. These are very picky machines and sound quality suffers a lot if they are misaligned. Needless to say that cartridge quality plays a serious role in audio signal reproduction.


Owning and maintaining vintage HI-FI gear is a time consuming task. You need to clearly think about it. Does it worth the time you invest (loose!?) in maintenance for a few hours of use per week? A computer could deliver constant audio performance at any time in the day or night. There might be better uses for your time.

But if vintage audio equipment is your call, then I can guarantee you will enjoy every moment you spend with this hobby. Otherwise, I am issuing a simple warning that could save you a lot of time: raise funds and buy quality new gear. Sure, the price is several orders of magnitude higher but the cost of replacement parts for the vintage devices quickly adds up to the lower acquisition price.

You know better what suits you. Don't let yourself fooled by what people say on forums or auction sites. Judge for yourself, experiment, and only then take your decision.

your help matters

Please note that all the work presented herein this site is non-commercial. This is my hobby and I am doing this in my spare time. Through this page I freely share my knowledge with you. But if you like my work, please consider helping me buy a transistor or a capacitor for my projects.

Thank you!

Copyright © 1998- Alexandru Groza