Chaotic relaxation
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This circuit is one of the ones I'm most pleased with, as it's a design that I've come up with I haven't seen anywhere else from a pair of simple relaxation oscillators that is capable of producing very complex sounds (partly it's nice having an oscillator without a feedback inverter at it's core). Each oscillator is modulating the other's pulse width, and there are two possibilities for disrupting the circuit with crystal diode clipping, the input signal is also fed into the circuit and there is a breakout jumper so multiple of these modules can be chained for longer feedback loops. I haven't tried much of this yet.
It slightly bends the variscan synthesis rules in that it works in an interesting way even without a crystal in the circuit. This makes it more forgiving in a live setup, but it gets more interesting with a natural semiconductor, and exhibits differences between different minerals.
I messed up the output stage, it needs a 2K resistor and probably another to ground to increase the output impedance and reduce the voltage to feed the low pass gate module.
Licenced under the CERN Open Hardware Licence Version 2 – Strongly Reciprocal
Inputs
- Choice of two locations for a crystal diode: X1 limits the buffering like a soft clipper (needs connecting to work when not in use) and X2 hard clips the input to the first oscillator.
- CV input
- Audio input feeds into the circuit.
- Breakout location to chain multiple chaotic relaxation oscillators together.
Controls
- OSC 1 pitch
- OSC 2 pitch
Outputs
- Audio signal
Schematic
PCB layout
