Yamaha CS-80 Synthesizer Sound Selection Circuit Analysis

[@alex97594]

"it was simultaneously the apex and the death gasp of a certain synth design paradigm" - poetic and absolutely correct. Your channel is awesome!

[@pthelo]

I'm consistently blown away by the depth of your knowledge in every one of your videos!

[@BellToneSynthWorks]

aww thanks!

[@calinguga]

just discovered the channel, this is a treasure trove.

[@pthelo]

@@calinguga They are cool people- good vibes - and incredibly skilled in their work. I'm a fan!

[@lights80088]

What a smart lady. My hats off to you.

[@andrak5946]

I just found this video, please i need to see a second part!!!!

[@totallyunmemorable]

Astonishing how much effort went into an instrument that would be rendered virtually irreparable as a result of the ultimate complexity of it all. Hammond organs same thing, simpler technology (in a way) but just an amazing amount of work went into the design and the building of the thing. Thank God there are still some around that rise to the challenge of restoring these things.

[@guitarstringman7403]

I am floored by your videos. I've done some elementary electronic repairs on my gear, but now my brain is hurting by knowing everything I DON'T know. Thanks so much for this insight. Another great video.

[@reflexivmusic]

How can someone be so damn cool, I AM IN AWE

[@fugamantew]

Lovely in-depth explanation of a mystical type of troubleshoot for us mere mortals… This is a gem of a video-thanks for sharing!

[@richardhines8622]

This was a instrument for gifted musicians. It’s response was unmatched. It’s ring modulator was the finest even to this day.

[@sea-saw2654]

My tiny mind can’t comprehend how anyone can understand complex electronics like that as far as to repair what’s presented in front of you let alone design it from scratch 🤯 superb video 👏

[@JorbLovesGear]

Excellent insight on the service manuals, (on a much smaller scale) I had a great experience with the moog/realistic mg1 service manual. Really straightforward troubleshooting steps. Great video, looking forward to more.

[@BellToneSynthWorks]

that one is unique because due to the fact that the MG-1 was a mass market product sold at Radioshak and targeted to people who had never used a synthesizer before, the service manual likewise seemed to be targeted at technicians who had never worked on or possibly also even used a synthesizer before. So it really goes back to basics and doesn't assume you already know any of the basic synth-specific concepts, which makes it a great resource for synth-tech beginners!

[@ssssssssssss885]

Must have been that the CS80 was probably designed/built by a division with a VERY specific set of skills and tooling. The harness is pure manual labor horror. Great insights and knowledge!

[@dastafford]

I just discovered your videos, and I know nothing of anything withing these videos, but I find it all absolutely fascinating. I hope you are able to release more videos.

[@georgeray3492]

There are few technicians willing to dive into the CS-80. I will follow along. Mine is in need of a check-up in the future. Your comment chain with Scott is enlightening and fascinating. Loved your explanations. While the P-5 did offer digital recall, the CS keybed and the ribbon controller put it in a different type of instrument. The P-5 is closer to an organ, where the CS-80 goes beyond what was possible with even a piano, with aftertouch- and poly aftertouch at that.

[@randelosborne6409]

What a fantastic video! I appreciate your understanding of this iconic instrument, and your willingness to share your knowledge in a clear, articulate manner. I especially liked the analysis and animation of the IG00157. Great work!

[@peekpen]

Hello. Multi-sampler/Songwriter here who just DLed the schematics of the "notorious" convolution/inversion/induction _feel_ of the Yamaha cs-80. I sincerely hope you keep going. Thank you for continuing to pursue this project.

[@djfredmiami]

Her degree of knowledge is fascinating.

[@mr_whyy]

wait this channel is a god damn gold mine !

[@jeffrogers210]

Bless anyone who works on CS-80's! I may need y'all soon.

[@robarkskillie960]

Awesome walkthrough... definitely a public service. Thank you.

[@shanedunne8488]

Definitely my favourite among the videos of yours I’ve seen so far. Thank you for not being afraid to dig into details!

[@richardkell4888]

Fabulous presentation, much appreciated here!

[@leeselectronicwidgets]

That’s awesome Alison, thankyou! As mentioned at the start of the video, the old circuit operation descriptions from the like of Sequential and so on are beautiful to read. This video (and I hope a load that follow) are wonderful to explain the arcane designs in a lot of synths. Thankyou again!

[@pete3897]

Hi Alison from a fan in New Zealand. What a wonderful endeavour to document the undocumented! Bravo.

[@jsomoya8368]

This is great! I was always curious how the CS-80 did what it did outside of the CPU/DAC paradigm. One wonders if Tom Oberheim ever contemplated going down this road before Sequential's CPU breakthrough and just thought the complexity was a nonstarter. Japanese manufacturing had a unique culture during this period (mid 60s to mid 80s). Everything from instruments and electronics to motorcycles and cars to bicycles. I have several Yamaha instruments from this period (synths and drums...). Great quality instruments that still work perfectly. Lots of unique problem solving that went the extra mile to squeeze every bit of functionality out of the technology they had.

[@properginko]

You are very good in explaining these complicated things.

[@ewanstefani]

Fantastic! Definitely interested in seeing more about the inner workings of these unobtanium synths, and the broader implications for synth design. Thanks :)

[@davida.p.9911]

With all those wires, it's amazing that something doesn't short out constantly. And I imagine dust and dirt getting inside there does a number on it as well. I have a 1983 Yamaha that uses the play card system, unfortunately it's monophonic and not as near as complex as that one.

[@kevinnolan3592]

Amazing video! And this CS80 looks impeccable - not a spec of dust - quite incredible.

[@IvanStepaniuk]

I became fascinated with the Mellotron since your videos on its internals. Great content!

[@martijndekeijzer]

me to! haha ;)

[@sawsquaresinetube]

Yamaha’s are beautifully organized inside ❤️

[@BellToneSynthWorks]

it is just an illusion!

[@sawsquaresinetube]

@@BellToneSynthWorks 😁

[@infindebula]

@@BellToneSynthWorks aww come on, something can be archaic and beautiful at the same time! When I see the inside of something like a CS80 I think of the perfection of all those string-tied wire looms. It is a technological cul-de-sac; the end of an era without microprocessors; and a triumphant example of what could be accomplished without them. Akin perhaps to Space Invaders - but somehow so much more.

[@BellToneSynthWorks]

@@infindebula ok fair enough, the fact that wires aren't ripping off constantly is certainly a testament to their wire dressing skills! as I said in the video, it was both the apex and the death gasp. It was Yamaha willfully hitting a wall!

[@Muselectron]

I'm not familiar at all with electronics, but I really feel that this kind of videos is a treasure vault and they might be really helpful and important, so please keep 'em coming! And thank you for sharing your experiences and knowledge!

[@DestroyER82]

Im die hard fan of Yamaha CS synths (for me they simply are the best sounding and most musical analog synths ever made). And exactly as you said, they are pretty simple to understand (even me, as quite an amateur in electonics, can understand pretty well what is going on), but the practical part (how is everything connected / wired and handled) is real madness for only the best techs out there. Looking forward next video, this is awesome and keep up the great job!

[@funkster007]

Fascinating stuff. I think we had one of these beasts in our Electronic Music Repair class back in the 80's. (We had access to many Yamaha products). I forgot how much of a nightmare this was to delve into lol. Great breakdown of this synth though, and my teacher would have been impressed.

[@Fluxwithit]

Very interesting video. Thank you!

[@KeritechElectronics]

Whoooooooa, just look at all those cable looms and assemblies... So intricate! "Very simple" on the module level, but way more complicated on the device level. Diode logic FTW.

[@DavidLee07]

Very cool to see an in-depth view of certain aspects of CS-80 design. In this case, the price of sounding great is high in every sense, from the pocket book to the potential for breakdowns from a single resistor... But I still love CS-80s!

[@EvilDragon666]

Definitely interested in more videos about famous synth innards! :)

[@MikeFox1]

Wonderful video. Would definitely like to see more...

[@infindebula]

I found myself scratching my head as to why Yamaha would go to the trouble of designing and fabricating something like the IG00157 when it’s basically just a couple of flip-flops. I presume the semiconductor market then was very different - ICs, even simple logic ones, were likely much more expensive and less reliable than they are today, so Yamaha decided to be in control of their own supply. Yamaha had many custom ICs that seem to be little more than simple logic and/or mux/demux circuits. They’re just different enough from today’s commodity parts to be a pain in the ass! I know just enough about electronics to be dangerous, and I don’t yet have the skill to devise substitutions for this type of stuff. This is why I plan to bring you my ailing CS40M from Toronto once the pandemic BS is over :)

[@Scodiddly]

They might have already built those chips for a motorcycle or something. ;)

[@kaitlyn__L]

Really looking forward to the next more general overview video! Though this was still fascinating. It really is a ton of patch leads in wire harnesses and selection logic to connect or disconnect them, huh? Also calling that bank of sliders “memory” reminds me of dip switches connected directly to specific memory addresses in early computers.

[@bubuAudio]

I'm fascinated by the topic and by this woman !!! nice videoo

[@gregoirearmaos7944]

Great video! At 11:20 you say you'll other cs80 vids. Have posted them yet? 😀

[@pushpull76]

...what i've found! Thanks for sharing the knowledge!

[@buddhabillybob]

Fascinating channel!

[@KeytarKris]

Awesome classic synth🎹🤟

[@jimfischer4703]

Excellent. Thank you.

[@matthewwilson3673]

great technical knowledge

[@clowtanne]

Thank you Allison!!! Great video!!👏👏

[@hindleygj]

Lovvve your channel and music !

[@trevsie7]

Very interesting, thank you for recording this. I take it modern synths encapsulate all this and more in just a few integrated circuits and are much more reliable. Why would anyone want one of these old unreliable synths restored to working order?

[@GunnerVFox]

They sound fantastic, and have been used by many skilled musicians to produce iconic music. Vangelis, the composer for Chariots of Fire and Blade Runner said the following about the CS-80: "the most important synthesizer in my career - and for me the best analogue synthesizer design there has ever been ... It needs a lot of practice if you want to be able to play it properly, but that’s because it’s the only synthesizer I could describe as being a real instrument, mainly because of the keyboard - the way it’s built and what you can do with it." If you are in to this kind of thing, there is nothing else out there that quite has what the CS-80 has.

[@ish233]

Neat, the video was like a mind massage and I'd be interested to see more. But the question who lifted it up on the table? Is it really that heavy?

[@stopthephilosophicalzombie9017]

@Bell Tone Synth Works. Where did you learn all the electronics needed to work on these machines? Are you self-taught or did you get a degree in EE?

[@danielpirone8028]

Thanks for sharing! More like this!

[@lunarthyme]

brilliant video, thank you :)

[@dls895]

muy clara la explicación, espero con ansias los próximos videos!

[@jamesmarchione170]

When I was dropping my prophet off the day before easter you were really ragging on the CS80 and now I know why. This is the goofiest 'logic' circuit. It just seems like its designed to fail. Okay, there ya go "if you have just 1 shorted transistor..." I think if I had one of these I would just have you disable the preset system, Its not like you can gig with it. Bring on the next video!

[@blimolhm2790]

wow what a privilege and head spin of a task!

[@splitradix]

I've got a CS60 which works fine apart from being stuck on "Sustain II" mode even when I switch it to "Sustain I". The switch itself looks alright, is there any IC that might be faulty that could cause this? I'd pefer it stuck permamently on "Sustain I" mode if it had to be stuck!

[@olafwagner]

Wow, fascinating video thank you. My overriding thought is though, if one were to physically remove all the presets (which arguably are the weakest part of the CS-80 anyway), and just keep the panel sliders and 2 sets of 'memory' sliders, the synth would be significantly simplified.

[@bborkzilla]

No wonder those things cost a fortune. That harness must have taken days to install!

[@BellToneSynthWorks]

I know! The inefficiency of the design also made it inefficient to manufacture.

[@sonikboom007]

Every time i see the inside of a cs80 my brain says... well ya... thats why theyre sooo damn pricy haha

[@davidgonzales720]

May I ask what tools you use for your animated circuit illustrations and diagram highlighting? Really enjoy your content. Thanks.

[@BellToneSynthWorks]

the schematic highlighting is just me running a screen recorder while I highlight PDFs in Acrobat reader! The schematic animation was done with the circuit simulator at falstad.com/circuit

[@skrie]

I quickly had to close this video so my wife didn't catch me looking at woman who can also fix my CS80.

[@fa0179]

Very cool

[@Gildermesh]

Very intresting, looks like you no longer post video's saddly

[@Mark_Ocain]

Nice synth was the CS80. I hear it came with a truss for use if you chose to move it LOL. It was a HEAVY beast! The wiring reminds me of an IBM S360 mainframe CPU and peripherals LOL...miles of spaghetti.

[@davidliddelow5704]

Would be a real pain to fault find with that amount of wiring. Usually in industry when you see that many wires they number them with tags at each end. Also you get problems with corrosion in the connectors adding resistance which can cause intermittent faults.

[@HazeAnderson]

Yet people revere these synths as some kind of marvel of quality. 😂

[@Pauleyh2]

Your amazing you know your synths from a-z

[@billywaters.as.billythekid8498]

real cool your friend billy

[@JedShura]

I was wondering how difficult it would be to interrupt the circuitry of the CS-80, to add "control-voltage" of the oscillators? It isn't on the market yet, but I'm hoping that the new Behringer DS-80 (an analog circuit exact clone of the CS80) will be able to be "hacked" to add frequency and sync cv inputs.

[@toppobrillo]

cool video !

[@GNeuman]

Clever lady! 👏👏❤️❤️❤️

[@xoio]

Wooooosh! How'd my head look as you did your flyby? :-D

[@jamesshort9750]

It's wasn't too quick at all. I'm no tech and can barely read simple schematics, but I got it. Thanks.

[@wajobu]

An interesting contrast is that Yamaha Service Manuals for their audio equipment of this era are VERY helpful and descriptive. I wonder if the opaque nature of the CS80 manual relates to them wanting to protect their proprietary design.

[@empowers67]

where does one go to learn all of this stuff?

[@toddmarshall7573]

I have a Yamaha Montage. It has a KApro CS80 library. I wonder how close that sound is to the CS80. It has just over 150 presets.

[@andrewp1400]

How do you have so many amazing synths 😅

[@jaggass]

I'm holding a minutes silence for all those roadies that had carry them around and set them up night after night and the engineers that had to repair them.

[@StrangeQuarkStar]

How practical would it be to replace these parts with a digital solution? Wouldn't one "just" need a digital potentiometer per parameter per voice?

[@BellToneSynthWorks]

Not quite! Also, a digital potentiometer is not a standalone thing, it's just a term people use for a potentiometer being encoded digitally. here's what you would actually need: - multiplexers with enough channels for every slider - a digital to analog converter (DAC) - a microcontroller running custom firmware (presumably also hosting ROM and/or RAM for the preset data) - an analog to digital converter (ADC) - demultiplexers with enough channels for every CV destination - a sample and hold circuit for every CV destination it's a pretty big redesign!

[@ЕвгенийСветлов-й8е]

Я в 1983 году стал владельцем Ямаха CS5 Вещь!🎉❤🎉

[@busywl69]

she could build her own TARDIS 🙌🙌

[@morphoice]

This rather simple design in theory would make it possible to change presets by putting in different resistors!?

[@mattm3729]

Do you make any music?

[@fabiancardenas6604]

great vid : )

[@CeZero4]

I love girls when they into technology. I wish to marry some once, unfotunately probably it never happens. Please add some videos more often. Simple repairs or even just box openings would be interresting.

[@schitlipz]

Need its sound playing in the background. Otherwise, neat.

[@BlondieSL]

It's sad that often, Yamaha's "service documentation" is sub-standard as well as them no longer stocking parts for older equpiment. I had a Yamaha HS8. I was able to find the service manuals, parts list and schematics for it. The schematics were "not too bad" but not 100% either. But using my DSO scope to monitor digital channels at one time, I traced the problem to a main processor for the pedals and keyboards. I won't go into details. I called Yamaha and other places only to find that they no longer had this processor chip or any other parts for the HS8. I hunted around, but no one had evne used parts. That was a sad day when I had to accept that this wasn't going to be fixable, all due to 1 main chip! uggghhh! So, I disassembled it for parts as the 2 main keybeds and the pedal boards will be used for another project I have in mind. I then was able to pick up a Yamaha HS4, which is better than nothing, but not feature-packed like the HS8. Oh what fun!

[@Peste_noire]

❤❤❤!!

[@RolandElliottFirstG]

Fran from fran lab lives in your city also

[@adeptus2022]

Это круто ) сам радиомонтажник 4 разряда !

[@goldmanfox]

🧐😳😮❤️❤️❤️❤️👍👍👍

[@jaggass]

The CS-80 makes the human brain look simple.

[@fjfrancois]

Wow, I wish I had at least one desktop clone of this beast. 😞

[@xKatjaxPurrsx]

Give Behringer a few more years and we'll all have cs80 clones at dirt cheap prices.

[@HazeAnderson]

I hope that as the video series continues you will learn that the interface is what makes the CS-80 ... all of those controls have to be cloned too. ;)

[@stopthephilosophicalzombie9017]

Why "Bell Tone"?

[@Goearthtour]

Spaced out here.... Hahaha you make Rube Goldberg look like a simpleton.

[@MePeterNicholls]

We need more women in electronics. 👍🏼💕 your channel is fantastic

[@mr_whyy]

80 bucks for such a chip is so expensive even if i understand why they are so expensive 😅 I just wonder if using a modern MCU is a possible replacement given some re-wiring ?

[@crebegea]

Fascinating, although I am not into electronics and practically neither into synths!