Thread: 811 home brew
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Old November 4th 07, 10:53 PM posted to rec.radio.amateur.homebrew
cliff wright cliff wright is offline
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First recorded activity by RadioBanter: Jan 2007
Posts: 58
Default 811 home brew

pinball_wizzard_01 wrote:
I've been playing around with tube equipment since I was 17. I'm now
21 and building an old school transmitter. I'm running two 811 push
pull tube system, and the power supple is a ver impresive two 866 in
parallel system.

I'm hoping to have it finished by the spring, I have the power supply
finished and I look forward to starting the transmitter

Just a query. Is there any particular reason why you are using the 866's
in parallel?
Remember a half wave rectifier puts a lot more strain on your HT
transformer. Perhaps though you don't have a centre
tap on your secondary winding! Also if you had 4x866's in a bridge
circuit you would need an awful lot of heater windings.
Many years ago I built a parallel 811A grounded grid linear amplifier
which worked quite well but of course with directly heated tubes you
need a really beefy filament choke!!!
Best of luck with the project and remember to always keep a hand in your
pocket while playing with 1500 to 2000 volts.
Regards Cliff Wright ZL1BDA ex G3NIA