'Ripples' - more PT2399 glitchiness

I made this as a custom pedal for someone, it's based on my earlier experiments with crossfading between dry and delayed signals using a basic square wave tremolo set-up that turns on one of these signals at a time. Using the PT2399, it's easy to also modulate the pitch of the delay signal by sending a synchronised pulse to the chip's VCO.

The crossfading idea morphed into this 'PT2399 glitch Delay' that I struggled to implement without a bunch of clicking coming from the LFOs (there were 3+ square waves whizzing around the circuit at once, it's a lot to tame!) In the end it became a patch for the Episodes digital multi-FX pedal.

This is the schematic for 'Ripples', the simpler one-delay design in the vid above. It uses a microcontroller to achieve the Size and Density set-up and to generate the pitch mod pulses. You could recreate the basic concept using a standard square wave oscillator and inverting the output for one of the tremolo LFOs, then possibly "randomising" it somehow with XOR gates for example.

A good trick for semi-randomizing the crossfades with CMOS would be to incorporate the divider tremolo technique, so the crossfades are sub-divisions of the audio frequency. It shouldn't be too hard to mash these schematics together!

To switch up the pitch modulation and get lower notes, simply invert the pulse that's sent to the PT2399 VCO.

I used two voltage regulators to keep the audio and LFO power lines seperate, reducing clicking. The caps in parallel with the vactrol LEDs also help a ton with this.