Technically it wouldn't be too hard to make a 2 voice paraphonic synth with digital waveforms, a nasty analogue filter and distortion, so I'm going to look into that. To keep things fairly simple there would be no presets, each knob would be immediately active like a Juno 6 or 303 or a modular.
I like complicated synths as much as the next guy, with plenty of mod options and the ability to store a heap of patches, but sometimes I just want something really simple, distinctive sounding and fun to play. Anyone else in the same boat? A lot of my favourite patches on the Evolver have so much distortion on them that you can't hear what the subtle modulations are doing anyway, this would be a synth for that kind of stuff.
Depending on how it goes I'll document everything I've done and release it as open source, so anyone who's interested can make one themselves.
This is what I'm thinking so far:
2 digital oscs, with a few different waveforms. Messy digital waveforms. They'll play in (carefully detuned) unison if you play monophonically or if you play two notes they'll split. That way you can play power chords.
(Or maybe I could get them to play octaves if you played mono... Hmmm, I'll have to return to this thought)1 digital envelope for the filter.
1 digital LFO, routable to either the oscs or the filter. Maybe with some kind of tricky blend knob.
1 Analogue LPF, something with a bit of character. Pre-filter drive mandatory.
1 Analogue VCA, fed with a CV out from the digital control. I'm thinking with an overdrive control.
Due to the way the Atmel chip works the digital section could only have 8 analogue (ie pot) controls. The LFO would have to have rate and amount, the Envelope would need some controls too, at least Attack and Decay, or maybe full ADSR.
That leaves either 2 or 4 controls for the oscs. What do reckon would be useful? Portamento? Detune amount? Level controls? I'm kind of inclined to treat the osc section more like an organ or guitar and leave fine tuning/levels out of it. Maybe some kind of harmonics control would be good? Pseudo-PWM for all waveforms? (Shouldn't be too hard, it would just alter the rate at which the LUT was scanned)
Switches would be used for octave (so you could tweak it live), VCA env/gate, LFO waveform, OSC waveform and any other tricks I wanted to put into the code.
Analogue section would be easy, just controls for filter cutoff, resonance and drive. The env amount would be covered by the digital section, for both LPF and VCA. Could probably have a post VCA -> pre LPF feedback amount too.
So we're looking at a box with 11 or so knobs and up to 16 switches. Shouldn't be too hard to learn your way around, which rules out the need to have presets.
What do people think? Poly 800 on steroids?
I'm interested on hearing anyone's thoughts on this, although as this is going to be a bit of a self indulgent project don't be offended if I decide not to heed your well-meaning advice. 
