what are the three jacks at the bottom?
would it be possible to make the VCAs switchable to ring mods?
You can get the same sort of result by feeding two AF signals into a VCA via AM. Route 'signal' to the input and 'carrier' to the CV. Works best if you have a couple of attenuators before this, though. Had a Steiner-Parker Synthacon many years ago, and the final VCA was set up with a switch to use VCO3 for eaxctly this purpose.
Right...the VCA has to be something which doesn't switch off when you get the negative-voltage parts of the AM cycle. Have a look at: http://electronicmusic.wikia.com/wiki/Four_quadrant where the VCA-as-ringmod thing is explained. My bet is that Nyle's output VCA on the Synthacon I had was capable of working in this four-quadrant mode with VCO3's output, allowing for the ring-like results. Anyway, even in two-quadrant modality, you're going to get this half-waved dirty sound, which in of itself could be useful.
AF = yes, audio frequency. Old habit from way too much radio experience.
I understand the differences between ring mods and VCAs and the way they respond to voltage and polarity. I'm familiar with their similar sounds, but I want ring mods for their inverted signals.