Performance will be similar to a 250TH or any other large glass low mu
1930's tube used as a SSB linear. Low mu by current standards anyway. Expect
IMD in the mid to high -20's which is right in the same area as sweep tubes
and 12V SS transceivers. It is also an inefficient tube above 20M, some say
40 especially for pulls.
With sufficient swamping and attention to layout neutralization may not be
required but its physical construction is a detriment to good isolation. A
250TH or 304TH/TL is easy to stabilize.
I remember a PP pair of 750TH's used only on 75M SSB running 7500V and a
30L1 as the IPA driver in the early 60's down in MA.
If you simply "must" use 833's then good luck. Im sure it could make ER
Magazine (-;
Carl
KM1H
----- Original Message -----
From: "Gary Schafer" <garyschafer@comcast.net>
To: "'Mike Waters'" <mikewate@gmail.com>; <amps@contesting.com>
Sent: Wednesday, December 19, 2012 1:48 PM
Subject: Re: [Amps] Has anyone ever actually build an 833A linear?
You will need a push pull type of grid circuit in order to neutralize
them.
The bridge type circuit will not work well.
If you just swamp the grids with a resistor and use a step up transformer
it
will take more drive than it is worth.
73
Gary K4FMX
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Mike Waters
Sent: Tuesday, December 18, 2012 4:24 PM
To: amps@contesting.com
Subject: Re: [Amps] Has anyone ever actually build an 833A linear?
Well, two grid-driven 833Cs in parallel may or may not be as linear as
the
best expensive ceramic triodes in G-G. But if it's linear enough not to
make my signal much wider, it's good enough for me. If it generates bad
key
clicks and spurs, then I'll build another one with the GS-35B I have,
and
say we learned something.
I plan on swamping the grids, and probably using a broadband step-up
transformer to get the grid voltage needed with 100w drive. With a
string
of 18v 10w zeners for grid (not cathode) bias. I already have all those
components; why not breadboard something and try?
73, Mike
www.w0btu.com
On Mon, Dec 17, 2012 at 4:58 PM, Carl <km1h@jeremy.mv.com> wrote:
> Its not a very linear tube for SSB, great for AM.
>
> Carl
> KM1H
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