Recently bought a 3-channel Dual Rectifier and when I first turned it on, I got this really bad buzzy sound. Seemed to have gone away once I turned it off and back on and worked fine for several weeks including for practice. Started having the same issue again and have traced it to the Bigfoot. When the buzz starts, if I press the ch2 or ch3 button, buzz goes away. Doesn't happen without the bigfoot plugged in and not every time either. This weekend, I plugged in and got no buzz but I couldnt get the channels to change at all. Brought it back home and now it's back to the buzzy thing but channels will switch. Bad cord, plug, relay, pedal? Any ideas?