SutterCane,
For heaven's sake, relax. Everybody is NOT having a problem with the EP500, nor did anyone "drop the ball". Please.
The EP500 puts out a prodigious amount of low-frequency energy, and it may excite other objects in the room into resonance, or (rarely) a screw or wire inside the EP500. Sometimes a wire may shift in shipping and vibrate, or a screw may loosen and need tightening.
Sometimes I think there's a kind of "phantom" resonance, like a poltergeist, that develops in the frequent posts on these boards. I've moved my EP500 around, taken it apart and re-assembled it at least four or five times during product development, replacing and exchanging prototype amp boards and I've never heard any vibrations (other than those in my living room!) emanating from the EP500. Which isn't to say that in the odd case, it may not occur. Hey, we sell a lot of EP500s!
But no need for panic.
Regards,
