I remember sitting in front of the Commodore 64 around 82 as a kid, trying to figure out the modular synthesis operations possible. With its then quite advanced sound chip, a MOS technology 6581. But it’s better known as the SID 6581. I have been getting busy with some electronics and Arduino stuff lately I might just make myself a midi sound module or such based on that chip. Anyway, it was at that time a big feature one up for it’s intended market audience, the hobbyists. I was somewhat left to my own device to figure things out, mind you we didn’t have Internet then so a trip to the library was the best thing to do. To my chagrin they did not have a single book on hand. So I just did what I do and fiddled with some parameters and quite possibly invented New Wave or Emo doom! Hahaha good fun that was. But this schematic will sum it up greatly for you, know fire up that Oberheim Bristol plugin or the many classics available on Linux and throw some switches and turn those knobs!