Sounds crazy right? Let me explain how i found this situation. I saw a video that explained how to convert a tube radio into an amp. One thing lead to another and now i have true vintage tone. Now here comes the spooky part... Turning off the radio, with my guitar still plugged, i turn the volume knob to zero on my guitar and i hear a continuous buzzing/zapping noise inside my guitar. What i suspect is that my jerry rigged amp is now sending current into my guitars ground. P.S. the radio has no ground on the plug.