• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

My amp is acting like a transducer!?

my amp is acting like a transducer!?

So I recently fixed the buzz on my EL34 amp but now something even stranger is happening. With no speakers connected I can hear the music playing back from the amp itself. The sound seems to emanate from the OPT's. Its mostly the higher frequencies from about 2kHz onwards.

When I hook up loudspeakers the amplifier plays alright but doesn't sound as good as it should. The highs are harsh and the overall sound has a veil to it. Any ideas whats going on? Are the OPT's busted?
 
Most OPT's will "speak to you", even when loaded. The sound from the speakers covers it up. Some are louder than others, and potted ones are usually silent. You have a lot of magnetic field being modulated by the audio. Any metal that can vibrate, will. Usually it is the end bells.

Operating a tube amplifier without a load can indeed take out the OPT, and other parts.