RFI - radio frequency interference. I'm picking up radio stations when trying to profile amps with my Kemper Profiling amp. I also had the same issue at night with microphones too. Here's the deal: you run a guitar cable from your guitar into the kemper, then into the amp input. this is one of the connections for profiling. Well, when I do that, I get a local AM radio station, and the more gain/volume on the amp, the louder the station is. I'm using good guitar cables - Canare GS6 with G&H ends. Do they make a special super shielded cable? This is driving me fugging nuts and pissing me off! The Kemper has a ground lift, but when I do that it makes a HORRIBLE buzzing noise.