Originally Posted by
Excalibur
You misunderstand, Toby. I'm not talking about it running the night when the power goes off, but simply for it to take out any nasties from an errant generator, and in the case of a cut, to allow you a controlled switch off.
Aha! And there we may have the answer. Sadly, Toby may easily have guessed correctly earlier.
It's possible that the load on the generator was too high, and caused the voltage to drop, which your amp didn't like. I don't know if switching amps are voltage sensitive. It certainly sounds an interesting problem.