I’ve always fantasized about some small toy-like Casiotone with lots of sliders with good and usable sound, well at least in my younger days. (Actually, I think there’s a Casio SA series ToneBank keyboard laying around somewhere at my parent’s house.)
Anyway, now I’ve found one – the great sounding Yamaha CS01. It looks good too, it fits perfectly next to the SH-101.
The CS01 is an analog monosynth from 1982. The sound is much bigger than its tiny frame would suggest. The PWM is just great. It might not be the best synth for bass, but it would definitely produce competitive lead sounds.
The CS01 has an uncommon feature, a breath control, which is an optional mouthpiece controlling the VCF and VCA. I reckon it’s mostly a gimmick, but I don’t have it, so I shouldn’t really judge. Moreover, the synth has a built-in amplifier and speaker, it runs on batteries (or external power). There’s also pins to attach a shoulder strap like on the SH-101.
If I could decide, I’d trade the breath control and speaker for other features, like MIDI or CV gate, or the ability to mix the noise with any of the waves, or sample and hold on the LFO. I would also change the step-wise glissando to a regular portamento (however, it is nearly continuous with a short setting).
Some say the mark II of the CS01 is superior with its 24 db voltage-controlled filter and adjustable slider control over resonance, but I think the original version is good enough, and I usually don’t modulate peak level that much anyway.
I got it pretty cheap, although I had to repair the pitch lever (the pot was broken). Vintage analog synths on eBay can be overpriced, but this should be one of the less expensive.