Weird "Ground Potential" Experience

[thomasdj]

Hi,

Saturday I was playing live and had a "ground potential" problem with my amp. When we did the setup and sound test there were no problems but when we should play I turned the amp on and the amp had massive noise! This was only on the distortion channels..I also noticed some not very hear-able but "very" high frequency sqeels at the clean channel...

However, all this only happened when I turned my guitar volume pot to zero :S

I'm suspecting the stage light for causing the trouble but I can't remember if it was on during the test and setup..

How do I cope with this next time I play live? - can I do anything to my amp?

Best regards

Thomas

btw..My amp is earthed via 3 wire IEC

[techineer]

I suspect you may have a bad guitar volume pot. It may have a broken wafer or other defect which breaks the circuit somewhere and leaves the cable (and possibly the entire guitar pickup assembly) hanging as an unterminated open line. This would then pick up any and all buzz, hum, radio signals and who knows what else and feed it to your amp.

Try a different guitar and see what happens when you turn its knob to zero.