[sdiy] Tube amp problem

[René Schmitz]

Hi Justin!

To me this sounds like you didn't connect any load to the amplifier. 
In that case the tubes can arc over from large inductive kick from 
the output transformer. That would explain the blue light and the 
buzzing sound. 

Cheers,
 René



At 14:36 03.05.02 -0500, Justin Herrmann wrote:
>Hi, my senior design lab final project is to design a vacuum tube guitar
>amplifier.  The output stage uses two EL34's.  The first time we
>(our project group) powered it up, one of the tubes made a buzzing sound,
>then it made some popping sounds and emitted flashes of blue light, at
>which point we turned the power off.  We rechecked all the connections,
>put in two new tubes (or valves), turned the amp on again, and one of the
>tubes made a hissing sound, so we turned the amp off before anything could
>blow.  I really have no idea what could be causing this.  Does anyone have
>any suggestions?  You can see the schematics for all the parts of the
>project at http://people.eecs.ku.edu/~herrmann/sdl/tubeamp.html
>
>							-Thanks-
>							-Justin Herrmann-
>
>
>
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