> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Bill, W6WRT
> Sent: Wednesday, July 22, 2009 7:17 PM
> To: 'Ham-amps'
> Subject: Re: [Amps] Grounded grid 8122's
>
> ORIGINAL MESSAGE:
>
> On Wed, 22 Jul 2009 20:01:52 -0400, "Carl" <km1h@jeremy.mv.com> wrote:
>
> >
> >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.
>
> REPLY:
>
> I guess we will have to agree to disagree. In both circuits the drive is
> applied
> to the cathode (or filament). As long as the grid and screen are
> maintained at a
> steady DC level, whether ground or some DC level, and have zero RF
> applied,
> the circuit function is identical - the cathode is driven, the grids are
> not.
>
> As to the Super Cathode Driven circuit somehow being different from GG,
> The only
> thing I see is the matter of DC bias. In terms of RF functioning, what
> exactly
> is the difference?
>
> 73, Bill W6WRT
How would you propose to run a tetrode in class AB1 with the grid and screen
directly grounded?
73
Gary K4FMX
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|