If you turn the guitar vol knob all the wsy down and the hum goes away, its not a ground loop.Ok, I have this issue of ground hum with my AX8. It only happens at this one venue where I regularly perform. Every other venue that I play at, I have no problems. Now, I have run into ground loop situations before and I think I know most of the troubleshooting steps. However, this one has me stumped. I've tried adding a ground isolator to my signal chain and hum is still there. Tried different electrical circuits, ground lifts, turning off stage lights. All to no avail. I am running stereo out with XLR cables direct to mixer and using IEMs. To get through the gig, I have to push the noise gate pretty hard which kills my sustain/tone. Again, all other venues the AX8 output is quiet. So, if anyone has some other ideas/solutions, I would greatly appreciate your input.