I just got my Behringer BX3000T (Yeah, I know...) B Stock and Avatar B210 Neo. I am getting a buzz. I plugged a cd player directly to the speaker cabient, no buzz. I plugged my headphone amp (that I made) after I converted it to mono, no buzz. I just plug the amp in, no buzz unless turned up all the way, then faint. If I plug a guitar cord in, bass plugged in or not, I get a horrible buzz. Doesn't go away even if I turn down the gain. So that means it is the amp when something is plugged in. It does have a 1 year warranty. I just emailed Musician's Friend about it (since Behringer says contact retailer first). That's about all I can do, right?