The super-rare Sony PCM-601ESD decoder

The rarest of the Sony PCM encoder/decoders usually used with Betamax tapes, the PCM-601ESD is the only one to have a factory installed S/PDIF digital output.
Further information since this video was made: I have found that tapes with glitches in the recordings, can trip out the Tascam digital audio recorder with a message about invalid input. But the same tape when played on the 501 with aftermarket S/PDIF output does not upset the Tascam. So to some extent, the 601 solution is not as good as a 501 plus Whistlewood board. This may be because the aftermarket board has more modern ICs.
It's also worth noting that due to the sampling system on this format, the right channel is delayed by half a sample compared to the left, which could be adjusted in software on occasions that it makes a real difference.
Audio and video transfers: www.video99.co.uk/
Please support us on Patreon / video99couk
or Paypal to [e-mail]
Service manual information was from:
freeservicemanuals.info/en/
Music “Let It Run” with permission, copyright Cristie/MacFarlane.

[@3dmaxuser]

I used to use those 601 converters when I worked at a studio in Soho in London. Watching this video really brings back some great memories.. if I remember right we use to like them up to our AMS Audio file machines... we stopped using them once we got a few Sony PCM 7040 dat machines. Great video thank you 😊

[@VCD-Channel]

Greetings from russian PCM collector! Watch your channel with huge interest and I want to say thank you for the video with early PCM processors (PCM-100, PCM-1600), this is very unique content in the Web! I have been looking for a PCM-601 but want to say that these processors not so rare and they really can be found on US or Japanese online auctions. But what is really hard to find that is Hitachi PCM-V300! The Internet has photos of 2 or 3 of these PCM tape recorders, one of which is mine :) But nowadays an old professional PCM machines (such as PCM-1610/1630, DMR-4000 and others) are also becoming quite rare.

[@danieldaniels7571]

Hey VCD! Your last video about PCM processors motivated me to buy one. I just got a Sansui PC-X11. I chose it because it was inexpensive, working, has all standard connections and is switchable NTSC/PAL. Unfortunately it is just 14-bit, but the sound is great and the format is fascinating. Thanks again for opening my eyes to these.

[@VCD-Channel]

@@danieldaniels7571 Wow! I never thought that my video would motivate someone to buy a PCM processor! Super! Glad that your bought it! Sansui made great machines :)

[@peterurbanek2611]

I still have two 601’s cabled in sequence…great equipment

[@Capturing-Memories]

They do show up occasionally on ebay, I was as happy as you are when I got mine.

[@Capturing-Memories]

My serial # is 800XXX

[@prestonsmith783]

There is a common fault on older F1's and 601's that the ceramic resonator, which is part of the clock recovery on playback, goes out of spec. If you listen carefully you can hear a low level noise coming from the clock recovery from video. If you copy the recording to another device via the digital output, you'll find that this noise is gone. It's just an artifact of the measures Sony had to use to recover the audio from the video stream. I worked with these systems very extensively for many years and know many of the quirks. All in all, it was an amazing system for its time.

[@kenfrancis7082]

That lithium tantalate will get you every time, won't it?

[@andrew1479]

I have a useful little unit a FriendChip Pro-Con which is a Digital audio format converter (AES-SPdif/SPdif-AES). It also allows SPdif to SPdif with a switchable SCMS defeat. I think it dates back to the late 1990s.

[@video99couk]

I've found that a balanced to unbalanced cable is all that is required for AES to SPDIF these days since most modern recording equipment (like a Tascam DR-100MKII) accept both protocols seamlessly. But the SCMS defeat might be handy sometimes.

[@Lior1973]

I have one of this at home ! And it's still working.

[@video99couk]

The 601 is quite rare so you're lucky to have one. Strangely though I found that the 501 plus third party S/PDIF output works slightly better than my 601.

[@musk771]

I have mine from year 1989, modified with cannon XLR retro-fit, BNC video connectors and insulated power supply. Still works like a charm with VHS and U-matic recorders, near my PCM-501ES and PCM-1630 with AES/EBU interface. For me these are special things.

[@video99couk]

I'll be doing more on this format shortly....

[@musk771]

@@video99couk What do you exactly mean about better performances of the s/pdif modified 501 against the 601? Less reproduction errors/drops? More stable synch?

[@video99couk]

@@musk771 That's very easy to demonstrate, and perhaps I will in a future video: If there's a corrupt bit of recording on the tape, the 601 sends out invalid SPDIF data causing the Tascam SS-R250N digital recorder to abort. But play the same tape on the 501 with the third party modification, and the Tascam just carries on happily when the tape is good again. I'm hoping my next video (after the one about to release in a few hours) will be about this format again.

[@musk771]

@@video99couk Interesting. Did you tried to record that tape with a corrupted bit via the 601, with another digital recorder, to be sure its not a problem caused by the Tascam? I have encountered various weird behaviors between digital equipments , and most of the time caused by some incompatibility or minor differences on its interfaces. For example the PCM-1630 connected to a MOTU 308 digital interface via AES/EBU does not send any audio. When connected in same way to an Apogee PSX100 ADA converter , the signal pass without any problem.

[@video99couk]

@@musk771 My only other recorder is a Tascam DR-100MKII, I'm expecting that to do the same though I could try it. But since the 501 with the third party board works so well, I've just shelved the 601. I'm yet to find a digital output route for my PCM-1630, what is your connection set up for that?

[@stephan.scharf]

... and here another owner, bought it in late 80s 😀

[@4FrameMusic]

Just acquired a 601 myself. I was running some tests by sending audio to it via SPDIF in, and then recording audio back to my interface via SPDIF out. With my gear slaved to the 601 at 44.1KHz, the clock signal drops every few minutes and forces my interface to re-clock itself, resulting in an audio file with silent spots. Do you slave your digital gear to your 601 when recording? If you do, it could be my VCR causing the issue. Do you recommend any specific VCRs for transfers? I was thinking of going for a Sony editing VCR with a REF-IN so that I could genlock it to the studio sample rate using a video/audio genlock/wordclock sync box for perfect transfers, but not sure if that would make a difference either. It's slightly above my head at times. Thanks for your videos!

[@video99couk]

I don't use my 601 because of problems like this, instead I use a 501 with Whistlewood interface which doesn't throw out the SS-R250N every time there is a glitch. The best players are those where the normal Dropout Compensator (DOC) function can be switched off, such as the SL-C9 or SL-F1. Or you could modify almost any Beta machine to be able to bypass the DOC function by referring to the schematics. I should do a KZbin video about doing that to a Sanyo VTC5000 or similar one day.

[@alphabeets]

Many years ago I had a Toshiba VHS VCR that allowed for PCM digital audio to be recorded on the video track. I still have the VHS tape but no way to play it. I’m wondering if it is possible to somehow extract the digital audio somehow without the Toshiba VCR. Any ideas?

[@video99couk]

I'm not sure what format the PCM would be, but it's likely not to be of the PCM-F1 standard. Do you know what the model number was?

[@arnoldvanheyst6325]

Still have the 601 (pal), for sale.

[@jamesbennettmusic]

Does this use copper buss bars for grounding points on the bottom board? I recently had to repair our studio's Sony R7 reverb which is known to run quite hot, and over time, the board warps and cracks all the solder joints on the buss bars and around the ADC circuitry. Never seen anyone else design a circuit board this way.

[@video99couk]

No, I don't believe so. There are copper strips on the top of the boards which you can see around 7:36.

[@jamesbennettmusic]

@@video99couk yes this is what I mean - rather than a double sided board, they just ran copper strips along the top. Never seen anyone else do that.

[@video99couk]

@@jamesbennettmusic I thought those strips were used as screening, but you are probably right, they could be earthing buss bars (or both functions).

[@KylesDigitalLab]

These were used to master early CDs.

[@video99couk]

Yes they were, though the more expensive (if less robust) PCM-1610/1630 Umatic based format was used more commonly.

[@KylesDigitalLab]

In theory, couldn't you digitize the video at a high bitrate, and then use software to decode the audio signal (undo error correction and other metadata in the stream) based on the pixels and output a bit-perfect PCM stream? I'm not sure if the decoders/encoders do anything with the blanking intervals though. I guess there's not really high demand for losslessly ripping PCM videotapes, but couldn't this be done?

[@video99couk]

There is software available to do this, which I've been experimenting with. At the moment though I'm still getting far too many errors with that route.

[@KylesDigitalLab]

@@video99couk What are you capturing with? What is the software called? I recently just got a PCM-F1, finally. Yeah I really want to mod a SPDIF input and output into it, but like I don't know how to solder lol. I would assume if you have the service manual and schematic you could make one yourself, but would be super hard since you need to undo the encoding and then re-encode as SPDIF. I would also not want to do any permanent damage to the unit like drilling a hole into it for the plug. I believe the DAC they used in the PCM-F1 is the same one they used in the CDP-101 in 1982? Always wanted to put a SPDIF output into a CDP-101. I don't have one but I just love the retro design of the CDP-101. Speaking of SPDIF, I have an old Sharp CRT TV from 1997, I was playing around with it and I found out it will actually display a SPDIF signal as a black and white "moving barcode", similar to these adapters. I have no idea how it does that, but looks very similar. I might upload a video of it.

[@video99couk]

@@KylesDigitalLab The SPDIF circuit is a little complicated, it involves a Phase Locked Loop to recover the clock signal. I have a copy of the software here but I can't remember exactly where it was downloaded from! It's Russian or similar. I'll update this as soon as I find out.

[@KylesDigitalLab]

@@video99couk Ok. Also is there software that does the reverse? (digital audio to PCM-F1). I recently got a PCM-F1 as a companion for my SL-2000/TT-2000 and I think it would be a really good digital audio recorder if I figured out how to get pure digital audio in and out of the unit. The only problem I can see is the 44.056kHz sampling rate. Does SPDIF even support that? Also if the software is Russian you might have got it from rutracker, that's a Russian forum, they have things like that. Hope that might jog your memory :-)

[@video99couk]

​@@KylesDigitalLab The Russian software does not do the reverse as far as I know. 44.056kHz sample rate would be from NTSC tapes I think. PAL tapes are a little easier. But I've captured NTSC tapes via S/PDIF. The software was mentioned and linked to from a forum in English, somewhere! I do wish I had taken notes at the time.

[@seanmangan2769]

I have one of each; 501 and 601. Should probably sell them because I don't have a VCR anymore.

[@video99couk]

The 601 is probably worth big money, though the 501 plus third party board actually seems to work better (it doesn't send an invalid S/PDIF data stream when there's a tape glitch as the 601 does).

[@seanmangan2769]

I have a 501 and a 601.

[@video99couk]

The 501 is quite common but the 601 is a rare beast. However I've found I get better results with the 501 plus Whistlewood add-on, than the 601. The audio capture system aborts if the 601 hits a bit of corrupt tape, but that doesn't happen with the Whistlewood PCB in a 501. So I always use that 501 setup. I now also have a Whistlewood board in my 701.

[@abijeetrs6522]

Can these be used to function as a normal DAC ?

[@video99couk]

Insofar as it has S/PDIF in and audio out, yes I think that would work. Never tried it.

[@dailyraillive1492]

Another amazing video. Sony video 8 does 10 hours at 12 bit right? Sod the video. AUDIO. 🤣

[@video99couk]

Up to six stereo pairs each of up to 4 hours on a long play 2 hour tape. That's all very maximum though.