| I think it adjusts the output gain. Mine used to be loud as @#$% but now it is just a little loud. I think they were set for use on guitar and the low freqs make it boom.
Mark where it is now, turn it counter-clockwise and enjoy your new, mellower Micro Q-Tron.
(note: I changed mine using a set of headphones and then took it to my normal rig days later for the final test. I believe my findings to be accurate, but I may have just convinced myself that I fixed a problem that I didn't. Marking the location of the pot will assure that I am not leading you down a dark, painful road of despair.) | 
