I noticed recently that my tube Jadis amps exhibit a buzzing sound through my speakers. Since I utilize a dedicated 20 amp line for these mono blocks, I was surprised tha this could be an issue. To check the problem, tonight I plugged both amps into the line utilizing a cheater plug for both power cables. To my surprise that fixed the problem. Question is what could be causing this grounding issue...the power cable, or the actual in wall receptacle? The receptacle is supposed to float ground...but is that the issue, or is it something else? Thoughts?