[sdiy] Simple VCA schematic, anyone?

[JH.]

>Jürgen, you mentioned a single-transistor VCA in the Korg PS-3200.
>Is it in the signal path ? That machine sounds marvelous.

http://jhaible.heim.at/polykorg/PS3200_Voice_Cards_orig.gif

The single-transistor VCA is right after the VCF. (Q401 ... Q412)

The single-diode(!) VCA is in the feedback path of the VCF. (D401 ... D412)
(Ok, the latter is more like a VC shunt resistor, and doesn't go to zero.)

JH.