Just got this amp, brand new. It's bone stock, and here are its problems... When it's running at its best it still gives off a pronounced hum at any volume, and there are metalllic sounding buzzy ghost notes that ring the exact same duration every time before abruptly stopping. This only occurs with certain notes on the low strings. Also, there is a seriously obnoxious buzz that comes from the chassis itself when the amp is turned up to 4 and certain low notes are struck. A far worse issue is an intermittent cutting out, whereby the amp either fades all the way in and out or it gives off a horrifically loud static-y whooshing sound. Giving the amp a good smack on the top can make the whooshing problem go away, but it returns fairly quickly. Conversely, when the amp is working as well as it can, giving it a good smack can make that horrible static-y swooshing sound come right back. Simply bringing the amp to a music store today was enough to induce the loud static sound. It's very unstable. Again, though, even when it's working at its best it still gives off the chassis buzzing and the metallic-sounding ghost notes. Playing my amp alongside an identical new one in the store, their amp was dead silent. Turning it up to 10 allowed for a normal amount of white noise hissing, but there was zero humming. It was a commendably quiet amp. Mine gave off a noticeable hum, in addition to the chassis buzzing. I just tried swapping out each tube, one by one. First the pre's, then the rectifier, then the power tubes. No change. Same hum, no matter what. Same chassis buzzing. More importantly, smacking the center of the top of the amp still causes it to fall apart and, conversely, return to its normal, slightly flawed state. So, it's not the tubes. In the meantime, yes, of course it's under warranty, but it's my only amp at the moment. Until my other new amp arrives, I don't want to turn this one over to a repair facility that will keep it for a few weeks. If I pull the chassis and have a peek inside, what might I look for that I could actually fix without a soldering iron and much greater electrical knowledge than I possess. Any ideas?