amp hums when volume pot is off?

[Luthierwnc]

Hi guys,

Got a new one (for me). I'm trying to complete a build and ran across something I haven't seen or heard before. The amp sounds fine with the volume on but has a wicked-loud hum when the volume pot is off. The grounds check out fine.

Anyone else ever run across this?

Thanks, sh

[Jana]

Ground loop.

and/or

The wiper of the pot is loosing contact with the trace when it is at 0.

[tubeswell]

also check that both input jack tip switches are making proper ground contact when not in use

[Structo]

I have experienced bad pots that are new, so eliminate that possibility first.