I was in Guitar Center just looking around. In the used gear section there was Mesa Boogie head that didn't have a back cover. I counted 9 power tubes and I think 8 preamp tubes. WTF???? They have the used amps staged back to back and there was a guy trying a amp in front of the Mesa and he was sitting right in front of the Mesa so I didn't see what model it was. Who buys an amp with that many tubes? It must cost a fortune to retube that thing.