I'm trying to track down the source of a hum I'm getting, and am turning to the experts here. The situation: - the hum is reduced 95% when I touch any hardware on the bass, or the metal connector on the cable - it's happening in the room in the house I use for practice; I've had the amp and bass in a half dozen other places and not noticed the hum anywhere else - the bass is a CV Jazz, and the amp is a GK MB210. I've had the control plate off the bass and everything seems grounded and it looks like it's got shielding paint in the control cavity - this buzz is with both pups full on; I do get some buzz just about everywhere if I don't have both pups on, but that's expected Since the hum pretty much goes away when I touch any hardware on the bass, it seems to me the bass must be grounded OK, but that's just my inexpert opinion. I've tried a different cable with no change, so it doesn't seem to be the cable. The one thing that occurs to me now is that the light in that room is on a dimmer and that may be causing me problems; I'll play with that later. I've played other places with dimmers without the buzz but maybe they were different brands, or I was farther away from them. Now that I've thought of it that's my prime suspect. My concern is that it's the ground wiring in the house. I've got a multimeter but no other kind of test gear - is there any good way to check the wiring without buying a circuit tester? Or if not, any recommendations on a good circuit tester? And the overall question - what do you think is the source of the hum, how can I find the source, and what can I do about it? Thanks!