Looks like damage to me. I'm sure you tried without the bass knob already. I honestly don't think that the person that sold that to you even knew. The amp looks new enough they could have replaced it under warranty if so. I'm thinking shipping damage. I don't use a bass knob on mine so I can't really comment on how well those work either though. I do run two aq2200 strapped and would have guessed on it being in slave or bass knob. Anything else points to something a bit more major.
Sent from my SCH-I605 using Tapatalk 2
97 Suburban Nothing for now
05 Elantra Two 18" Custom DB Revolution Neo's
MECA 2013 TN Street 3 Champion
MECA 2014 Dueling Demos Street World Champion