[sdiy] Korg Volca Bass service manual

[Roman Sowa]

The VCF is taken from early Korgs. This is more or less what's inside 
those Keio submodules.
Using logic Schmitt inverter is not such a bad idea and seen in many 
simple designs. Although not even specified in datasheet, the trippoint 
of modern Schmitt devices is pretty stable.
What's more interesting is the use of the-cheapest-of-all LM324 for 
everything except when low Ib is the key factor

Roman


W dniu 2026-10-26 o 22:00, Sean Ellis via Synth-diy pisze:
> https://cdn.hackaday.io/files/1698407266434560/korg_volca_bass_sm.pdf 
> <https://cdn.hackaday.io/files/1698407266434560/korg_volca_bass_sm.pdf>
> 
> Not sure if this has been shared but here's the manual, as usual some 
> interesting circuits from Korg. Schmitt-trigger in the VCO and a very 
> low parts count on the VCF, not a trimpot on board! Has anyone heard one 
> of these? I'd be interested in how the filter sounds.
> 
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