Yamaha CS-15

Yamaha CS-15 Image

This synth really has its own sound. The CS-15's got style. Built like a tank with a lot of nice knobs and best of all, not one but two of those funny sounding multimode filters. It's actually a duophonic / bitimbral synth but you have to connect it to CV (Hz/V like Korg not V/Oct) to get the extra voice. Each of the two VCOs has its own CV/Gate control.

Yamaha CS-15 Image

The best things about it are the flexibility of the VCFs and the routings to the filters and envelopes. You can rout VCO 1 to both VCFs and the VCFs to any of the envelopes positive or negative voltage. The VCFs are 12 dB/Oct and are switchable between low, band or high-pass. They are the key to the nice sound of the Yamaha CS family. Other nice features are noise, external-in for processing other sounds, LFO with Sample & Hold for those bubbling sounds and an individual auto-bend for the VCOs.

Yamaha CS-15 Image

The CS-15 is great for strange blips, bass and tiny highpass sounds. The ADSRs aren't as fast as the CS-10 but they are ok. A nice feature is the 'brilliance' slider that can control either or both VCFs. At their extremely low prices, the CS-15 is an analog that's definitely worth checking out for yourself. It has been used by Astral Projection, Somatic Responses, Moog Cookbook, The Human League, and Vince Clarke.

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40 Visitor comments
james pilcher
December 26, 2010 @ 5:55 pm
solved my problem - not a fault - see the cs-5 page for the facepalm-worthy solution
james pilcher
December 16, 2010 @ 6:05 pm
I just bought a CS-15 on ebay for £400. It took an hour of knob twiddling to get a consistent response from it - the pots and switches all seem to be filthy as hell, which is no biggie, but the only vaguely disturbing thing is that it emits a continuous tone, even if you let go of the key. it's like the VCOs are stuck or something. If I have the brilliance slider at 0 the effect is eliminated from VCO2, and if i reduce it to -1 it stops happening on VCO1 as well. I checked to make sure that the Release sliders weren't shorted or something, but you can hear the envelope go through all of the ADSR stages and still this tone remains behind the whole thing. And if you reduce the Envelope depth pots to zero it has no effect on this noise.

Anyone have any clues? I will clean all the switches and pots and if it still hasn't fixed it i supposed i need to start replacing caps. I don't really want to start replacing bits of it in case it affects the character of the synth.
Mats Sjöblom
November 12, 2010 @ 8:34 pm
I have had a CS15 since the early 80s. I used the external input a lot in the beginning, to add resonant filters to my Yamaha PS3 in lieu of a real poly-synth. The external input doubles as an analogue trigger input, so you can mic something up and hit it with a stick to trigger those filter sweep noise swooshes, or do percussive sound replacement. The keyboard action is springy and "Roland-like" and has high note priority, very nice for playing solos. The VCO waveforms are triangle (marginally useful), sawtooth (great sounding) and rectangle wave with optional LFO modulation of pulse width (fantastic sounding) - PWM. PWM based sounds is where the CS15 really shines. PWM appears to be always sine modulated regardless of what LFO wave form you choose (so PWM is still chorus-like with S/H selected), but it is locked to the same frequency as the regular LFO which is a bit limiting. You can't combine a quick S/H VCF bubbling with a slow PWM sweep.
October 25, 2010 @ 3:31 pm
I've had one of these in my attic for years. Also own a 2-year-old Motif XS8. Question #1 is can I connect the two together, #2 is there any reason to try to control one from the other, #3 if I sold it what would the CS15 be worth today? TIA!
October 13, 2010 @ 12:44 am
This synth was also used by Buzz McCoy of My Life With The Thrill Kill Kult
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User Rating

Rated 3.99 (589 Votes)

  • Check Price
  • The link above will take you to an eBay search for this synth to see active listings. If you don't find it there, try looking in our forum marketplace or post a wanted classified.
  • Specifications
  • Polyphony - Monophonic / Duophonic
  • Oscillators - 2 VCOs
  • LFO - One with triangle, saw and S&H waveforms
  • Filter - Two multimode (LP/BP/HP). Controlled by either or both ADSRs.
  • Effects - None
  • Keyboard - 37 keys
  • Memory - None
  • Control - Dual CV/Gate
  • Date Produced - 1978 - early '80s
  • Resources & Credits
  • Images from Perfect Circuit Audio.

    Thanks to Magnus Gladen for providing the review.

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