Amp is making a BOOM sound. Whats wrong??

[NOT]

It is coming from the speaker, and it is just a low booming sound that you can feel. The boom sound is small, but noticeable.

But the buzzing only occures when I plug in my old Epi T Bird. There is no buzzing when I plug in my Gibson Thunderbird, Frender Jazz, and Mockingbird.

 

[JKos]

So, you're talking about a power on transient that causes speaker excursion? This is not uncommon. Some amps do it worse than others, some amps do it everytime, some amps only sometimes, some amps do it when you turn them on, some amps do it when you turn them off, some amps do not do it.

The only way to know if something is actually wrong with your particular amp is to find out if others with the same amp have the same thing happen.

- John

 

[Bassmec]

Due to my superior language skills and a fair command of intergalactic accents.
I shall try to translate, I think when he turns on the amp it produces a loud resonant mains hum at circa 120Hz this may be due to a power supply capacitor fault or a damaged output device and its associated driver circuit.
Empirical Diagnosis: I think its got to go to hospital immediately for further tests.