I had this problem exactly. Two dunlop mini vol/exp pedals and they were going to zero to full to zero (0%-100%-0%).
I followed these directions below and it worked no problem.
Also the thought of opening these pedals and fiddling with soldering after spending all that money was just not an awesome feeling.
- i have a the Y cable that has two ends "ring" and "tip" looks like this https://www.sweetwater.com/store/detail/STP201--hosa-stp-201-insert-cable-1-4-inch-trs-to-dual-1-4-inch-ts-3-foot
- i went in and inverted the polarity on the Ring and Tip settings in Global settings. This felt wrong/weird, and i don't understand it and frankly didn't want to at the time.
- opened the dunlops (4 screws, took 1-2 minutes), flipped the tip/ring switch to "ring"
- same exact steps for both (I didn't make the settings opposite for each pedal or do things that felt right)
- closed up. all worked.
- pre-condition for it to work is settings it global settings are set for both expression pedals. one ring/one tip
