[Amps] grid fuses

[Tom W8JI]

> "...If it's open, the most it might do would be to attract 
> a few
> electrons being negative like was mentioned...(etc.)"
>
> In the old days this was called 'contact bias,' and was 
> the principle
> incorporated intentionally in a grid-leak biased stage.

People like to misapply what happens in a 12AX7 dual triode 
and other thumb-sized tubes operating at 50-300 volts P-G 
voltage to fist-sized tubes running at 3kv and more.

Contact bias generally does not work in large HV tubes and 
should never even remotely be considered a reliable bias 
method. It's bad logic and even worse engineering to 
consider contact bias reliable in power grid tubes. They 
don't even recommend it in 6AQ5's, let alone something 200 
times larger with ten times the HV (or more).

73 Tom