For packaging these mods, my first idea was to have a separate box attached to the pedal. It looked like a motorcycle sidecar so I had a box and a design ready.
But then I figured out a way to pack the 4 toggles inside the pedal enclosure. So I decided to use some point to point soldering instead. Here you can see the diode selector. One side has red LED and germanium, the other yellow LED and silicon. The switch is 3 way, so the center is off, no diode selected.
Here's the final gut picture.
Some technical details
I experimented starting with these references:
- Flat filter curve: R16=1K
- Mid boost: R16=250
- Less gain: R9=25
- More gain: R9=500
- Top: germanium, red LED, off
- Bottom: silicon, yellow LED, off
I also changed C10=.068uf to filter some shrills.