Where would you even get copper foil? Aluminum foil is common but not copper.
Wrapping power cords and interconnects with copper foil.
Ok..not sure other people have done what I tried recently but I’ve found a night and day difference in sound quality after I wrapped my tube power amp power cord (rogue Zeus) and my cheap audio quest interconnect cables with copper foil. I even wrapped by phono cable coming out of my turntable to phono pre-amp. The detail retrieval and pin drop silence after doing this has made by jaw drop. Cost was $40 worth of foil wrap. What do you audiophiles think? Have I changed the sound signature in a negative way somehow?