Hello All, I just bought a used pedulla thunder bolt (sweet) and had some functionality questions for anyone out there who has one or happens to know. Figured out the volume and pickup pan. Knob 1 and 2 respectively right? As far as the back two knobs, I'm not sure. The bottom most one in the back doesn't seem to do anything until its all the way clockwise. The uppermost back knob, is the tone I assume?