[Amps] al811h reverse grid current

[Kurt Cathcart]

Here is a pic of the sockets.  Does this look correct?

https://www.kuhlroad.net/572bSockets.jpg

-Kurt

On 2/21/2026 6:09 AM, gudguyham at aol.com wrote:
> You did it wrong.  The GDT do not replace the resistors on the grids. 
>  You remove the resistors and the caps to ground  on each grid to 
> ground on the tube socket.  You directly ground the grid.  Then one 
> GDT goes from rad filament wire to ground.  That’s the way it’s done.
>
>
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> On Friday, February 20, 2026, 7:19 PM, Curt Nixon 
> <radio.ku8l at gmail.com> wrote:
>
>     Look for a bad ground in the metering and or bias area.
>
>     On Fri, Feb 20, 2026, 7:12 PM Kurt Cathcart <Kurt at kuhlroad.net> wrote:
>
>     > Several months ago a seem to have a 572b go bad.  I replaced it
>     and also
>     > replaced the resistors with GDTs (amoung other mods).
>     >
>     > Now I'm getting reverse grid current and the GDTs and lighting
>     up.  I
>     > put in a net set of 572b and am getting the same thing, The view
>     of my
>     > Sockets matches the picture on the Instructions .
>     >
>     > Advice?
>     >
>     >
>     > -Kurt
>     >
>     >
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