[Amps] Dual tetrode in grounded grid

[Carl]

And there is always the pot in the screen lead B+ of the 6360 trick. 
Just dial in the drive you want.  I use a screen pot in the HA-6 5894 to 
drive a NCL-2000 at 15W or a converted Alpha 76PA at 100W. The 
3CPX1500A7 under construction will be somewhere in between.

Carl
KM1H



----- Original Message ----- 
From: "Glen Zook" <gzook at yahoo.com>
To: <Amps at contesting.com>; "Carl" <km1h at jeremy.mv.com>
Sent: Wednesday, February 11, 2009 3:16 PM
Subject: Re: [Amps] Dual tetrode in grounded grid


> Using an attenuator pad at the input is what I was considering.  Of 
> course I would rather use the power from the transmitting converter 
> for something other than generating heat.  Basically I was seeing if 
> using the 5894 in grounded grid rather than grid driven was possible. 
> I already have a pad on the input of the transmitting converter (to 
> drop the output of my FT690RII from 8 watts to 2 watts) that I am 
> using as the i.f. for the 222 MHz transmitting converter.  I like to 
> use 50 MHz instead of 28 MHz as the input for my higher frequency 
> units if possible although I am using 28 MHz for my 432 MHz SSB.
>
> I normally do use link coupling above 50 MHz including in the 222 MHz 
> transmitting converter which ends up with a 6360 mixer into a 6360 
> final amplifier.  I am presently getting a solid 5 watts out of the 
> 6360 and if I tune it carefully I can get a little bit more.
>
> Glen, K9STH
>
> Website:  http://k9sth.com
>
>
> --- On Wed, 2/11/09, Carl <km1h at jeremy.mv.com> wrote:
>
> Why not use a pad inside of the amp at the input link or tap?
>
> Looking at the tube specs Im not sure the 5894 screens are up to GG 
> use. Its pretty close to a pair of 6146's in that respect.  In AB grid 
> driven it is a very linear tube.
>
> Link coupling will make it easy to tune out any reactance from carbon 
> comp resistors. I do this with a partially HB 6M transverter with a 
> 6360 driving a 4X150A which started out as a P&H 6-150 TX converter 
> with a 5894.
>
>
>
>
>