Common Tube Amp Malfunctions: My amp makes no sound.

If your amp makes no sound, it is first important to define what you mean by “no sound.” To that end, the first test you should perform is whether you can hear anything coming from the speakers. (This is, of course, after you have eliminated the possibility of trivial problems.)

Listening to what (if anything) comes out of the speakers can help you isolate the problem to specific parts of the circuit. If you hear no sound coming from the speakers — including hum, hiss, reverb crash, input cable pop, or any other incidental, non-musical sounds — the problem could be the speaker itself. But, if you hear non-audio sound coming from the speakers, the problem is likely, although not guaranteed, to be a fault in the preamp section of the circuit.