BC

I built a clone of a MuTron III pedal a while back. It turned out well, and was one of the easier builds I have completed thanks to the circuit mounted rotary pots. I have not actually used this one very often in real life - usually when I want sounds in this world I will instinctively reach for a Moog, but it was a really fun to make anyhow.

The circuit is based off of a state-variable filter - there are selectable high-pass, low-pass and band-pass filters all on the same circuit (controlled by one of the toggled rotary pots).

The pedal includes a built in effects loop - this is because the filter responds with much more animation to a harmonically rich signal. Placing a fuzzed-out or overdriven effect in this loop produces more interesting filtering than a clean tone. The circuit takes the clean signal, which is more volume-dynamic, to control the envelope follower, and the harmonically-rich signal from the effect loop to have the filter applied to it.

The circuit uses an led and a photo-sensitive optocoupler to control the opening and closing of the filter. The dry sound signal is translated into voltage to create an envelope follower, lighting up a diode whose light is then received by a photo-sensitive cell and translated into the opening and closing of the filter in a more musical way. Way cool.

I got the enclosure drilled and ready (the least enjoyable part)

Populated PCB (and Wayne Shorters Native Dancer EP in the background for good luck). Mounting all the pots directly on the PCB saved a ton of time and eliminated many of the potential problems that come from wiring them up offboard.


And here is a quick demo of me trying to cop the sounds from Thundercats' Them Changes with the new pedal: