[Amps] AL-811H problems

[Vic Rosenthal]

"John E." wrote:
> 
> AL-811H up date:
> I  removed the top cover and found one tube was not lit.
> Removed all tubes and tested on a TV-7D/U.
> Found one tube was open.
....
> I have only had single tube amp's in the past, Will one bad tube on a
> muti-tube amp
> cause a SWR problem?

A dead tube will certainly change the input impedance to some extent.  It's
possible also that a piece of the broken filament in your dead tube is touching
the grid, which will change the input impedance in a MAJOR way (to close to
zero).

Vic K2VCO