Bass control stopped working
on rockford amps, the bass control knob needs to be connected to get the maximum output (+18 db gain i believe). If you did this to the power wires, then yes, you may have at least damaged the bass control knob. Try replacing this to see if you get all of your gain back. If not, then you have damaged something inside the amp...maybe a capacitor or power supply inside. If that's the case, you'll need to get the amp looked at by an electronics repair technician or local stereo shop.