I'm using a Whirlwind ABY box and got a ground hum from one of the two amps I'm going to. They are both plugged into a strip that has a 3 to 2 adapter on it because my house has old wiring. So I put a 3 to 2 adapter on one of the amps and voila the hum was gone. But I detected a shock when touching one of the cable jackets. So, I put an adapter on the other amp as well. No hum, no shock. However, I'm still paranoid that this may be a dangerous way to eliminate the hum. Any info would be appreciated. I may buy a Tonebone box instead.