So...I just got a BTB 6-String and I'm playing with the electronics. I noticed that, unlike the current BTBs, this one has a 3-way switch. Other than that, it's identical to the current BTB676. Does anyone happen to know what this switch does, cuz I can't figure it out. I've plugged it in, had both pick-ups on and flicked it to all 3 positions. It doesn't seem to make any difference to the sound.