I've been getting a very loud, lowish hum from my GK when my rig is set up the following way:
Pedal board: two one-spots and an EHX adapter into a power strip, which then goes into an extension cord. Amp plugged into same extension cord; extension cord goes into the wall.
The hum only appears when I put a cord into the input of the amp, and then only when the master (woofer) is turned up to anything above 0. Volume and EQ knobs have very little effect on the hum. The only things that eliminates it are removing the cable from the input jack or turning the woofer to 0. Not very practical!
I've tried without success:
- Plugging the amp into another outlet
- Removing warts from the power strip
- Changing instrument cables
I've tried with success:
- Skipping the extension cord altogether and going straight from bass/pedal with battery/amp (woo-hoo x100, and it makes me need to mention how much I love this amp!)
I have not tried:
- Changing extension cords
- Changing power strips
If I change either of those, should I find a shielded extension cord? A better strip (it's a cheapo IKEA strip)? Stop using effects and trade them in toward a Ric or some black tar heroin?
Oddly, this didn't happen when plugged into my GK combo. Again, the only way to make it work is to not use the extension cord, which tells me it might be that or the strip. I didn't have other ones to try out, otherwise I would have done it.