Amp makes "single coil" type hum

[Frank Prince]

I have a Rivera Chubster 40 w/EL34s that is making a hum similar to what a Strat pickup sounds like through an amp with the gain turned up.

This sound happens even on the clean channel of the amp with a guitar plugged in but turned all the way down. It is not super-loud, but definitely present.

Any ideas?

[axepilot]

Does it hum everywhere you plug it in? Bad outlet grounds and/or dirty line power could be the culprit.

[fragglerock]

My recently acquired suprema does the same thing. I suspect its coming from the AC in my house. Then again I took my first look at the tubes in it yesterday and its a mish mash of 12 AX7s and the power tubes seem to be on the way out as well. Methinks it is maybe not as new and unused as the seller lead me to believe. Even though it looks virginal...:eek: