PT2399 Glitch Delay

A way of making a glitchy choppy delay effect using classic DIY experimenter's chip, the PT2399.

A possible iteration of this idea ... See here for a clearer schematic!

Using three PT2399s that share an input, each set to different delay lengths, and turning up the volume for only one chip's output at a time, we can simulate the effect of skipping across time, forwards and backwards, glitching about the delay buffer. The volumes are controlled by three basic vactrol tremolos.

The above schematic has been through a few revisions but this one seems like the easiest to concoct. There are five pots on this one, Wet volume, a variable MFB Lowpass filter, a Time control done by connecting each delay's VCO through differently valued resistors to a common pot to ground... The micrcontroller then provides two controls, Rate, which is the speed of the glitching and Density, that compares it's value (position of the pot) to a constantly randomised number. When the pot value is more than the random number, the next delay line is turned up, causing a "glitch".

In the video I also used a PWM output of the microcontroller to modulate the delays through their VCOs. The capacitors in parallel with the LEDs help reduce audible ticking. It might be possible to vary these caps somehow to change how steep each tremolo's onset and offset are, essentially making the glitch transition smoother or more choppy.

You could replace the microcontroller with a decade counter, but I can't think how you'd set up a density control that way.

I'm still working on a full pedal for this design, hopefully with PCBs available too, but it's a tricky one to capture in plastic and copper. So far I've been trying factory-assembled SMD designs (due to the horribly high parts count) with varying degrees of success.

As a thought, you could transfer this idea to bucket brigate delays. Imagine that ... analog glitch delay ...