Buzzing Amps--- Solution?

[AckAckAttack]

I have a small problem and I was wondering if anyone out there knows a solution for it.
I've been jamming with a friend of mine, me on guitar and him on drums. I split my guitar through an A/B switch into a guitar and bass amp to make it sound more full. When only one amp is turned on, everything sounds good, but when both amps are turned on at the same time, there is a buzzing sound coming from the amps. It goes away when I am playing, but when I'm not it's pretty annoying.

Is this because of the electrical outlets? We jam in my friends basement, which has a few different power outlets. Each amp is plugged into a different surge surpressor from a different outlet in the wall so I'm a bit confused, looking for any guidance, any help is greatly appreciated. Thanks, -Dan.

 

[will33]

If either of those amps has a ground lift switch, try flipping it on one amp only. If that doesn't work, try plugging into different outlets or if you're already doing that try plugging into the same outlet. Just because you're in two different plugs in the wall doesn't mean you are on separate circuits. You can buy a little tester for your wall outlets for 5-10 bucks and check them for proper grounds too.

 

[AckAckAttack]

If either of those amps has a ground lift switch, try flipping it on one amp only. If that doesn't work, try plugging into different outlets or if you're already doing that try plugging into the same outlet. Just because you're in two different plugs in the wall doesn't mean you are on separate circuits. You can buy a little tester for your wall outlets for 5-10 bucks and check them for proper grounds too.

Thanks for the info, does this defenitely sound like an electrical problem? That's what I'm thinking but I didn't know if it could be something else.

 

[will33]

That's a good place to start, that's why a lot of amps have ground lift switches on them somewhere, usually in the back. You say it buzzes with both amps running but not with just one? I'd try that first. Single coil pickups and unshielded or poorly wired instruments will also cause buzz but if that was the case, your instrument should buzz in many different amps. Also check your cords and cables and check for loose jacks on the amp and cabs. If the bass cabinet has a tweeter and control for it on the back, try turning the tweeter down. That's probably as much information as you're going to get on this board until you put that guitar down and pick up a bass.

 

[billfitzmaurice]

You have a classic ground loop. It's caused by having the amps grounded together in two places, the AC supply and the inputs. An explanation of the cause and the fix can be found here:[Invalid or Expired Link Removed]