Harsh crackling noise after palm mute in Helix Posted August 5, 2019 Yeah it sounds pretty similar. It's dead silence when the guitar is not plugged in. In my case its interference from the old wiring inside the walls, as I plugged everything out in the room except the Helix and listend with my passiv headphones while walking around in the room. The sound got stronger when going up to walls and especially outlets. As it's not planned to redo the wiring anytime soon, I thought of getting one of those "Hum blockers". But I need to do more research on those, because for example the one you used didn't have an effect.