I modified the clock speed circuit of the Alesis Nanoverb2. See video here:
Digital audio FX use a crystal oscillator for the system reference clock speed. The DSP (Digital signal processing) circuit uses this base frequency to produce the length of reverb tail, delay echo, repeat speed etc.
Removing the crystal osc. and replacing it with a very precise, controllable digital oscillator (not the kind you can hear, this is in the Mhz range) enables analogue style, manual modulation over the digital clock speed of the system. I also add a vactrol circuit, to be able to animate the clock speed very quickly with a control voltage.
With the animation, extremely interesting textures and soundscapes are possible.
I have done the same mod in the past on several digital devices. (DMG Gameboy, ART MultiFX etc) It always surprises me what kind of sounds can come out of it. Each device is unique, and will respond to the clock changes in different (though similar) ways.
This is the revision 2 of the Nanoverb2. It's from 2011 so its the most modern device I have modded so far. Pretty much anything with a digital clock can be modified in this way, although, there are some machines which derive many OS functions from the clock, and become unstable (in a bad way) when you try and reclock the whole system.
This one is currently for sale: https://reverb.com/item/40007495-alesis-nanoverb-2-modified-circuitbent-cv-controlled-clock-speed-mint-with-box-manuals-psu-eu