Honestly, no need. It's just the treble knob got pushed down on the shaft a little bit probably during shipping. Just loosen the set screw, move the knob up a touch, done....the separate bass/treble control wont spin independently of each other. the bottom knob will turn 360 but the treble knob wont turn independent of the bass. the treble doesn't spin all the way around though. luckily i work in a repair shop and will have it looked at tomorrow...