I've got a Peavey Cirrus 4 (beautiful walnut/bubinga) and I love it.. now, I've had a little problem with some of the EQ knobs getting loose. at first I thought it'd help to just screw them on, but at last I realized that I should use that little wrench I got with the bass. however, by screwing the EQ knob a couple of turns, I had made a deep scratch in that little metal rod on the potentiometer. now I can't put the knob back. I think I ****ed that potentiometer. darn it.. any hints on how to avoid this happening again? (apart from not trying to treat the knobs as screws) and is it expensive to replace the potentiometer?