I bought a Sonzera 20 a few weeks ago. Sou ds amazing. So I plug i to it at home 1st day and dial it in. Use it at a gig that night. No problem. It sits for a,seek and I bring out to a gig. Clean channel hums so loud that the sou d guy shuts me off between songs. I have surgery so i dont get a chance to play with it until yesterday. Unbeleivable hum in the clean channel. I try a Humx and gound lift no change. Take it back to the store, no problem. I get a tripp lite iso bar back at my house and it still buzzes. My Blues Junior, my home made plexi dont buzz at all. Tomorrow since i am still recovering i am bringing my so to carry my blues junior and my Sonzera to like 10 different places and record if it buzzes or not. If it does I am going to want PRS to fix it or refund it. Anyone else have problems with these amps?