Okay, so I got the pedal and gave it a try.
1- 50k pot seems to work fine, getting 0 to 2.7v from bottom to top,
2- 100k pot seems to work better(better peak points), getting 0 to 3v from bottom to top,
3- 220k doesn't work, but getting around 3.4v from top to bottom, I think it exceeds the...