how hot is hot? tube amps get warm after a while of playing. thats normal.

what amp are you using? do u mean biasing the tubes?

btw, its not recommended that you do things yourself, especially with a tube amp. it isnt like a normal transistor amp. even though you unplug the amp and leave it for a while, certain areas might still have very high electric charges in it, messing around can lead so some serious injury.