[click for larger]
It started as the OrcaSynth (a mod of a HackADay project), turned into the DigiSynth, and now has finished off as SynthZilla!
The final build includes control over pitch, duty, portamento, 2 LFOs, tone, body, gain, vol, 8-step voltage sequencer, and more!
[click for larger]
Below is the schematic I used. Not all the components are labelled and I didn't draw in the bypass jacks for all the knobs, but you get the idea. Let me know if you'd like a cleaner, complete schematic and I will happily oblige.
[click for larger]
A couple notes: I used a quad-amp simply because I was out of single amp ICs. Also, the tone/body filter only works well through headphones or an external amp, not the onboard speaker.