Ground Loop

I just got my QC and love the FX sounds, espectially the verbs! I am using it 4CM with a modified Randall RM50. I have a pretty bad ground loop and not sure what to do about it. I tried all of the standard things like plugging into the same AC outlet, ground lifts, etc. Is there anything internally on the QC that I can try?

Go to the I/O view (swipe down from top of screen). There is a ground lift switch available by tapping on the Inputs, Returns, or XLR connections.

Maybe try swapping out guitar and cables also.

I tried all sorts of cables and that is not is. It is definitely a ground hum. I will try the lift on the I/O page. That is what I was looking for. Thanks!