Originally Posted by Nats
anywhere specific? all the grounding seemed to be ok
If the grounding is fine, it might just be noise, especially if you said you didn't notice it on your practice rig. It might be a joint going bad on a cable, just plain cheap cable, or just noise from the amp. See if there's still any noise on your clean channel and go from there. If you happen to be in front of a TV or CRT monitor, that'll do it, too.