I've been experimenting with Monotrons since around the time of the original's release. I took an interest in the Duo model more recently though. The extra oscillator opens up some modulation options, and paraphonic possibilities. I thought it would be fun to digitally control as many parameters as possible.
After experimenting with using OTAs to control things, I determined that digital potentiometers would be easier. Unfortunately, there has been an ongoing shortage with the digipots that the project calls for. Because of this, the project has been shelved for some time. While working on this, I developed some modifications that don't require digipots though:
- Oscillator sync
- XOR ringmod
- Squarewave anding
- Sub oscillator
- PWM
- filter HP input
- VCF crossmod
I'm posting now to at least keep the schematics from sitting on my hard drive. I hope to follow this up with a breakdown of each mod.
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| Full schematic |
