[Amps] Grounded Grid(Screen) 4CX250B power gain

Alex Eban alexeban at gmail.com
Tue Jul 21 05:57:39 PDT 2009


Yes, there was!
At the time it was one heck of a tube and you could get them as pullouts
from police and other commercial equipment for a song! It was then usual to
replace tubes at regular intervals, regardless of the operating hours. So,
pretty often they were real bargains.
Besides, at the time high μ triodes were rare and expensive, not, oh, so
linear! The 4-1000 had a reputation, well founded, of being quite linear in
this configuration. What's more we were loath to spend precious exciter
power in some input loading resistor so we relished transferring power to
the output.
Not to mention a cheaper and less complicated power supply!
Alex	4Z5KS

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of Bill, W6WRT
Sent: Tuesday, July 21, 2009 3:43 PM
To: amps at contesting.com
Subject: Re: [Amps] Grounded Grid(Screen) 4CX250B power gain

ORIGINAL MESSAGE:

On Mon, 20 Jul 2009 14:14:11 -0700, "Hardy Landskov" <n7rt at cox.net> wrote:

>Years ago we used to tie the screen and control grids together and ground 
>them in 4-1000's. It was very stable but took a lot more drive.
>Hardy  N7RT

REPLY:

I have never understood why people did this. If you want a triode, get a
triode.
I guess if you have a tetrode lying around taking up space but you really
want a
triode it makes sense, sort of, but is there any other reason?

73, Bill W6WRT
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