In a message dated 6/1/98 6:02:49 AM Central Daylight Time, realex@flash.net
writes:
<< Chris,
The 3cx3000 is very hard for the average ham to work with. First,
it takes 7.5 vac @55 Amps for the filaments. It does not work well
with less than 5kv on the plate and at that Ep it idles at over a
kw. The plate output capacity is rather high making it very hard
to design a tank circuit that will work on 15 ,12, and 10...the
Henry 8K design is for commercial use and not intended for amateur
applications. A well designed 3cx3000 amp will do 5 kw out easily.
73, Bob W5AH
>>
Bob,
Some good points, but running three tubes in parallel has got to present
problems as well. I suppose a better question to ask is why not use the
4CX1600 instead of two 3CX800s. I just got back from looking at Svetlana's
Web site and I have to say that the 4CX1600 looks attractive.
If you are running more than one tube, how do you know what each tube is
doing? Do you just assume everything is okay? I believe broadcast
transmitters meter each tube separately. In a way I meter my 3-500s
separately -- I look at the color of the plate which is hard to do on a metal-
ceramic tube. :-)
My friend who owns the 8K acutally never ran the amp above the legal limit
(believe it or not). He did, however, have the best sounding signal on the
band. I expect that linearity is excellent @ 1.5kw out even though efficiency
may leave something to be desired. I was surprised at the cost of the 8K. I
thought it would be quite a bit more considering your points made above. BTW,
the 8K is for sale if anyone is interested -- I can only dream.
73's
Chris, KF0FX
KF0FX@aol.com
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