Zachman":2y1egnyt said:
Iso transformers... of power supplies, w/ ground lifts
Depending on where the ground loop is-- you could cut the ground on one side of the audio cable from the source side of the ground loop.
You could star ground the entire rig
Aloha brother Zach, hope all is well
iso trafo's are heavy, bulky, expensive, and do not need additional ground lifts because they already isolate the ground plane from the primary source of power.
the second sentence is 100% true and this is the true method to hunting down ground loops, but unless the user has a good idea as to why ground loop hum occurs and how it occurs, its not likely the most accepted method sadly, and depending on the build, there could be multiple ground loops due to the (poor) design of the products being used.
star grounding the entire rig requires isolated points to attach the connections - its not exactly easy nor feasable if you arent willing to dive in head first and tackle each and every product in the signal chain. seems it would just be easier to fix the said electrical box, watch for cable placement in regards to the AC plane, good (shielded) cable for audio lines, and assuring the guitars are not to blame/shielding the cavities themselves