Just a quick question. Had been playing my Mesa 400 non plus before flicking it to standby and reading tb forums for about half an hour and decided I would try the 12U7 swap again. Took the lid of and the preamp tube was still really warm. So were the power tubes and the power transformer (i think. The one on the left when looking from front) was quite hot. I havn't noticed this before and just wondering if this is normal or not?