Help with Hum... ground loop, wiring?

[JoeNovice]

I've got an AC30CC head. It sounds great when it doesn't hum. I've tested the head at other locations and it's not the source.

I think I'm dealing with a ground-loop issue.

If amp is on without cable plugged in..... no hum

If amp is on with cable plugged into guitar.... hum, varies based on position of guitar.

If Ebtech Hum Eliminator is pluged into signal path.... hum changes but doesn't disappear unless I touch something metal like the standby switch or another 1/4 jack on my keyboard.

Ebtech Hum X didn't fix the problem.

If I touch the speaker cable while amp is on I can hear RF interference.

AHHH!!!!!!!! This sucks..... any technical comments would help.

[Darkbluemurder]

If amp is on without cable plugged in..... no hum

If amp is on with cable plugged into guitar.... hum, varies based on position of guitar.

Does your guitar have single coil pickups? They do hum by design, and it indeed matters in which angle you are standing to the amp.

[JoeNovice]

I've tried many guitars to the same effect.

Humbuckers, single coils, archtop.....

Hum or Buzz changes based on guitar movement.

[Brian Hill]

I've tried many guitars to the same effect.

Humbuckers, single coils, archtop.....

Hum or Buzz changes based on guitar movement.

Sounds like the ground wire to your bridge and possibly other grnds in the guitar are out of whack.

Brian

[JoeNovice]

On all three guitars???

I didn't have a ground problem on other amps that I've used at school lately.

[Brian Hill]

On all three guitars???

I didn't have a ground problem on other amps that I've used at school lately.

Oh sorry. I should have read it closer. Maybe the ground plug on the AC cord is screwed up. Did it just start happening all at once?

Brian

[JoeV]

Plug in the guitar and turn down the volume of the guitar. Still hum? It's the amp. Doesn't hum anymore? It's the guitar's shielding grounding.

High gain amps hum more than lower gain. Higher volume produces more hum. If it's the amp causing it (ground loops, tranny placement, etc.) it'll hum with the guitar's volume knob turned down.