Steve writes: "I thought you might get a kick out of this: It's a Compumedic Sciences Incorporated Modular Analog Computer from 1970." It's not really a music synth, but it processes control voltages. The auction says: "This unit would be suitable for use in experimental music as, electrically, it is compatible with any modular system (+/-10V)." It's currently $255 with two days to go. If nothing else, it would make a very impressive coffee table... More.