[Amps] Grounded grid 8122's

[Carl]

It is not semantics when you are discussing 2 very different amplifier 
designs. You appear to be the only one trying to combine them as one.

Grounded grid where the grids are at DC and RF ground is not the same as 
applying DC voltages to those elements that are still grounded for RF. 
Comparison examples would be GG 813's vs the THP HL1KA.

The latter is called Super Cathode Driven for a reason that easily 
differentiates it from a simple GG cathode drive.

Carl
KM1H



----- Original Message ----- 
From: "Bill, W6WRT" <dezrat1242 at yahoo.com>
To: "'Ham-amps'" <amps at contesting.com>
Sent: Wednesday, July 22, 2009 2:13 AM
Subject: Re: [Amps] Grounded grid 8122's


> ORIGINAL MESSAGE:
>
> On Tue, 21 Jul 2009 21:55:21 -0500, "Gary Schafer" 
> <garyschafer at comcast.net>
> wrote:
>
>>. There is a difference in what we all call
>>"grounded grid" and "cathode driven"
>
> REPLY:
>
> The difference is mostly semantics. A grounded grid amp where the grid(s) 
> are
> connected directly to ground is definitely cathode driven.
>
> By comparison, a cathode driven amp may or may not have its grid(s) 
> grounded for
> DC, but it must definitely have them grounded for RF (heavily bypassed to
> ground).
>
> Some tetrodes can function properly with the screen connected directly to 
> ground
> and others can not. It is all a function of the tube's internal design.
>
> 73, Bill W6WRT
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