[Amps] Has anyone ever actually build an 833A linear?

[KG8YN]

Yea, Paul,

I'm sure it gave the CE 10 a loud voice. I'd like to see your driver 
circuit.

Let me attempt to fill some blanks about your amp.  Hmm... Push Pull, 
amplifies both halves of the cycle, low distortion, absolutely the best way 
to go!  However, balanced in, balanced out.  So unless you single-ended it, 
I'll guess you used link coupling to a pair of air variables connected to 
600 ohm open wire.  Again, absolutely the best way to go!



And Mike,

We live in a coax world.  So if you want to use a parallel design, you 
should find plenty of info, use a design center curve, and halve the plate 
resistance for 2 tubes. Use a pi-net calculator, and the biggest components 
you can find!  The hardest part is the mounting and ventilation.  One manual 
says, "Direct an air nozzle to the top of the tube".  Look at the commercial 
broadcast transmitters like Gates and others, when 833's were popular. Make 
a variable bias supply.  The circuit should get you working.  For grid 
driven parallel, the swamping resistors are the best idea. Use 100 ohm 50W 
RF type on each grid.   A lot of fabrication will be required for mounting. 
I think the side fan is ok to blow between 2 tubes, but the chassis bottom 
mounts should be open with a lower chassis exhaust fan, and the use of top 
down blowers for tube longevity. Shop for ceramic standoffs, I have some 
square pillars and heat radiating caps if I can lay my hands on them.  I don't 
know how many 833C's you have, but e-mail me if you want to sell a pair.



Jim Lewis, KG8YN

kg8yn at neo.rr.com


----- Original Message ----- 
From: "Paul Kraemer" <elespe at lisco.com>
To: "Mike Waters" <mikewate at gmail.com>; <amps at contesting.com>
Sent: Saturday, December 01, 2012 5:35 PM
Subject: Re: [Amps] Has anyone ever actually build an 833A linear?


> One of my first linears back in about 1960 was a grid driven pp pair of 
> 833A
> I used four 6CL6 as driver for my CE 10B
> When it spoke it had a loud voice.
> Paul K0UYA
> ----- Original Message ----- 
> From: "Mike Waters" <mikewate at gmail.com>
> To: <amps at contesting.com>
> Sent: Thursday, November 29, 2012 11:22 AM
> Subject: [Amps] Has anyone ever actually build an 833A linear?
>
>
>> This article is in the 1980 ARRL Handbook, showing a grid-driven 833A in
>> linear service. But I have never heard of anyone actually trying it, and
>> I've done many Google searches.
>> http://www.w7ekb.com/glowbugs/projects/Universal%20Amp.pdf
>>
>> I have a bunch of 833Cs here (the graphite plate version of the 833A) and
>> am considering a 160m linear like it with two paralleled tubes.
>>
>> 73, Mike
>> www.w0btu.com
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