Hi,
I have a second hand Ultra XL module which had problems:
- almost no distortion even at full gain
- if i strummed real hard on the guitar i could hear some weird and loud distortion/clipping. This was more noticeable at low gain.
I thought that if the clipping is happening even at low gain...
So i bought a used RM100 and it came without a footswitch.
I wanted to try a low cost solution and i hacked this for arduino:
https://github.com/ramalhais/code/tree/master/arduino/sketchbook/midifoot
Hope this helps someone.