> I am new to the list so be kind! I went through all of the threads
> on amps@contesting.com concerning an amplifier using 833's and pretty much
> came up with very little usable information.
/*snip*/
> Plan.
>
> 1 Two of them in parallel or Push-Pull?
>
> 2 Grid driven with a 55 ohm, 75 watt non-inductive resistor to ground.
>
> 3 Pi output network or Pi L ? Or Link coupled output?
>
> 4 Operation is CW and occasionally SSB. Bias voltage on Cathode developed
> across about 60 V Zener to ground?
>
> 5 Power supply is capable of 3000 Vdc at 1 Amp.
>
> 6 Forced air cooling up from pressurized bottom chassis to box on top
> housing tubes and output components.
>
> 7 Tubes mounted in vertical position. Heat sinks for pin connections.
If I could come up with a pair of 833s I would build a P-P grounded cathode
amplifier.
(cross neutralized) I would use a tuned center tapped grid and plate coils and
I would
link couple in and out and I would use a (separate) link to couple the input
swamping
load. I would use a high impedance output link into a Pi or Pi-l network as a
harmonic
filter. All links need to be in the (cold) center of the tank coils and
shielded to
reduce capacitive harmonic coupling. If I could find the right triode, low
voltage high
current, I would make each a cascode pair to reduce the drive requirements, I
can only
think of four 811s or 812s in parallel or some such is a possibility. Of
course four 833s
would do just fine, but remember in cascode operation the upper pair would
require their
own heater transformers and chokes. For just two parallel triodes one
transformer will
serve both tubes without any chokes.
I have the 3.6 kV power supply and much more for such a project, with plug
in coils,
but no tubes.
--
Ron KA4INM - I'm proud to be Chuck's pop!
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