[Amps] Glitch resistors

[Gary Schafer]

Richard wrote:

> >I am working on an amp with a pair of grid driven 4-400's. What size
> >glitch resistor would be recommended for the plate circuit ?
>
> 1, 10 -15 0hms, 10w. vitreous enamel for up to 3kV.  2 in series for more
> than 3kV or >30uF.

This is a wire wound resistor ?


>
>
> > Also what do you do about the screen ?
>
> Bypass each screen pin (2 & 4)with two, different value capacitors say c.
> 500pF and 2500pF.  This helps VHF stability. Use 800v regulated on the
> screen.  A zener-string shunt regulator fed through a power resistor
> connected to at least a 1500v source is good.
> Tuning a grid-driven amplifier is different than tuning a grid-driven
> Class AB1 amplifier.  Info is on my Web site.

I should have mentioned before that the amp has separate electronic regulated
screen supply with a 12AX7 and a 6L6. My concern is how to protect the screen
in case of a glitch and the plate glitch resistor opens up. How do I shut
down the screen supply quickly enough to prevent screen damage when the plate
voltage is removed ?

>
>
> >Also what would be good for parasitic suppressers?
> >
> A low VHF-Q design proivides c. 60% lower VHF gain with the tradeoff of
> c. a 2% power decrease at 29MHz.  Ugly resistance-wire exhibits lower
> VHF-Q than beautiful silver strap.  We sell low VHF-Q suppressor kits as
> well as bulk materials.  Info is on my Web site.
>
> cheers, Gary
>
> -  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
> www.vcnet.com/measures.
> end

Thanks
Gary  K4FMX