Mains hum through amplifier

pinksoir

I've got a really annoying (what I presume is) mains hum coming through my guitar amp. It's there whether a guitar is plugged in or not. It's a bummer cos I want to record the amp (I was previously using a sansamp, but it's just not the same!). Its not the amp itself as the same thing happens with other amps, plus I've used the same amp in other rooms/venues and it's been clean.

Anyone have this problem before and know how to remedy it? Cheers.

peter05

What guitar, how are your leads. Is it a combo or 4x12?

fitz

pinksoir wrote: »

I've got a really annoying (what I presume is) mains hum coming through my guitar amp. It's there whether a guitar is plugged in or not. It's a bummer cos I want to record the amp (I was previously using a sansamp, but it's just not the same!). Its not the amp itself as the same thing happens with other amps, plus I've used the same amp in other rooms/venues and it's been clean.

Anyone have this problem before and know how to remedy it? Cheers.

Sounds like a wiring/grounding issue in the room, not the amp...

pinksoir

Yeah, it's definitely not the amp, it's the room. Any idea how to deal with it?

mkegvn

Do you have a DI box handy? If so try various combinations of including it in the chain, with the ground lift flipped. May help. But also, may not.

pinksoir

Cheers. The hum exists independently of the guitar, as in it's there whether the guitar is plugged in or not.

One other thing I've done is plug my sansamp straight into the effects loop, bypassing the preamp altogether. In this case I can turn down the EQ knobs on the amp which turns the hum down, though it's still there. This makes me think that it's the preamp that's receiving the hum.

mkegvn

Oh yes sorry, just saw the regardless of guitar bit. Presume you tried the amp in another room to see if that solves the problem?

pinksoir

Yeah, I tried that too. The amp is grand in other rooms/venues. I've gigged with the amp no problem. The same thing happened with another amp I had, a Fender Supersonic, so it's definitely the room I'm in.

pinksoir

Also, I tried using a two prong plug, a European dealy, so that the ground wasn't connected (not the safest thing I know!), just live and neutral. The hum became much much louder.

pinksoir

Ok, after some more digging it appears to be a stock problem with the amp. Luckily it looks like there is a mod to fix it. I tried the amp in other rooms and the hum's still there. I must just have not noticed it before... Ah well, at least I know now.

CrimsonSounds

Have a look at this here :

http://jhbrandt.net/GroundingWiringZeroLoopArea.pdf

There's some diagrams at the bottom of the document aswell which may be exactly what you are at - but great info in there anyway to help you ;-)