Tonite the power supply went to the great power supply resting place in the sky. Emailed JM on his disposition on this. As you might guess I expect it to be favorable.Does the buzzing get more intense when you modulate on AM? That's definitely a sign the RF is making it's way into the power supply. When you get into really big amps if there's enough getting in you can hear your voice plain as day. Not ideal. Although now that I think about it that really was more common with the older power supplies and not the switching ones. I've been using the MegaWatt for years without any RF issues on them even when testing some dirty CB amps.