[Amps] Grounded grid 8122's

Bill, W6WRT dezrat1242 at yahoo.com
Tue Jul 21 19:38:08 PDT 2009


ORIGINAL MESSAGE:

On Tue, 21 Jul 2009 21:00:00 -0400, Herzog <herzog at frontiernet.net> wrote:

>I dont believe there is any way to run a 4CX250 style tube in GG without
>destruction. Very few tetrodes have the necessary grid dissipation required.

REPLY:

GG does not require any more grid dissipation than grounded cathode. GG does
require more driving power, but not for the grid. The extra driving power
"modulates" the cathode current. Inside the tube, the grid-cathode voltage
determines the amount of grid drive and in this context the tube doesn't know or
care which element is grounded and which is driven. 

I am not saying that GG and GC are identical -they definitely are not, mainly in
the phase relationships between elements and the feedback present in the
circuit. But in terms of grid dissipation, they are the same.

73, Bill W6WRT


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