Hey guys, again I come to you for help. Last night at band practice I had issues with the volume on my M9. I was turning it up and nothing was changing. Just a SLIGHT increase in volume but barely noticeable. This is the second time this has happened. I noticed at the end of a jam last month but the following day it was fine. It's been good up until last night. Last night I bypassed the preamp by running my Sansamp in the return. Didn't change anything. Any idea what it could be?