I've just finished another board of my PS-3200 clone project.
This contains the "common signal" part, i.e. everything after the
49 individual voices: Keyboard balance, a very crude Ring Modulator,
the famous Resonator (MOTM-410 owners will find this familiar),
a VC Ensemble send/return and two VCAs. All Vactrol-based. But
I'm using the Vactrols differently than Korg did, building "real"
potentiometers from 2 vactrols each.
http://www.oldcrows.net/~jhaible/polykorg/jh_polykorg_clone.htmlJH.