SC20H Preamp Control Hum

[PeaceBuyer]

Bit late to the Party of SC20H's humming but I've been having an issue. When the amp is in standby there is no noise at all, but when it is in High mode and nothing is plugged in there is a low volume humming that can be controlled with the preamp volume control (gain control), and then whenever I plug straight into the High output this humming is loud and can't be stopped, even with preamp knob at 2 in the high input you can still hear it, but not as loud as when the knob is at 10, it is almost unnoticeable when plugging into the low input though, is this normal? I've read about people having completely quiet SC20H's and want to know if there is some sort of defect with mine (its still under warranty thankfully, already had to take it back once because the power light started flashing). I didn't buy this amp to have to put a noise gate in the effects loop as I don't like to use effects loops as its just more cables on stage, and noise gates out the front don't help the amp itself humming, but they do help to stop feedback and pedal hum.

p.s. the humming does increase in volume with the amp which leads me to believe it is something to do with the preamp, and I don't believe it my guitars or cables as I have used 3 different types of cables and 3 different guitars, all with volumes set to zero. Also the nearest possible source of interference I can think of is either a satellite on the roof on the other side of the room or a TV 2 rooms away.

 

[ByrdmanFL]

Bit late to the Party of SC20H's humming but I've been having an issue. When the amp is in standby there is no noise at all, but when it is in High mode and nothing is plugged in there is a low volume humming that can be controlled with the preamp volume control (gain control), and then whenever I plug straight into the High output this humming is loud and can't be stopped, even with preamp knob at 2 in the high input you can still hear it, but not as loud as when the knob is at 10, it is almost unnoticeable when plugging into the low input though, is this normal? I've read about people having completely quiet SC20H's and want to know if there is some sort of defect with mine (its still under warranty thankfully, already had to take it back once because the power light started flashing). I didn't buy this amp to have to put a noise gate in the effects loop as I don't like to use effects loops as its just more cables on stage, and noise gates out the front don't help the amp itself humming, but they do help to stop feedback and pedal hum.

p.s. the humming does increase in volume with the amp which leads me to believe it is something to do with the preamp, and I don't believe it my guitars or cables as I have used 3 different types of cables and 3 different guitars, all with volumes set to zero. Also the nearest possible source of interference I can think of is either a satellite on the roof on the other side of the room or a TV 2 rooms away.

I'll check mine out later and see if mine hums that way too. BTW, do you have any LED lights in the house or near the amp?

Mine has a him that comes and goes, so I just figured it was LED's and/or older house wiring. Plus my breaker box is on the outside of the room I practice in. Either way, for me, this amp rocks and it's so small I just deal with it