
"Features
* Dual oscillator mono synth
* Really easy to build using just 1 custom programmed PIC chip, 4 ICs and single 12v supply
* All circuits built on veroboard - no printed circuit board making skills needed
* PIC based dual oscillator and digital keyboard scan
* Analog VCF/VCA/Envelope
* Waveforms : sawtooth, square (with pulse width adjust), triangle
* Tuning presets : in-sync, out-sync, detune1 and detune2
* Expandable, first two modules shown below.
A real analog synthesizer to build using easy to get components, capable of a wide range of sounds. The two oscillators can be detuned for that classic synth sound."
More info including samples
here. PICSynth