just curious guys, what are the main ways excessive heat can damage and amplifier? I had a studio session last night, put my amp in the booth and didn't think twice. I let the engineer do his job... Well, he was a younger engineer and put a BIG SOUND DAMPENING BLANKET over the amplifier and microphone. I mean, he draped it ALL THE WAY OVER my '65 Deluxe. Didn't notice until about 3-4 hours later after the session when I went to retrieve my amp. The amp was HOT physically... not like burning your hand hot but VERY hot to the touch (more than normal). I have durable NOS tubes in there (marconi power, mullard preamp) but is it likely that this kind of treatment caused some kind of premature wear to my tubes? I tried to let it cool as much as I could before moving it (I packed it up last). Amp worked and sounded fine on the last take of the last tune so I guess it's alright... just wondering. Moral of the story is, WATCH ENGINEERS especially if they're young!