>... A local ham is offering me to buy
>his old Henry K-2000. As the salesman he is, he told me that this is the
>best amplifier you can buy HI.
>
>The amplifier is in good(?) shape, but need a new pair of tubes (8873).
>Are theese tubes easily available and
>at what prices?
The last price I heard was around $1k for two 8873s. If the kaput 8873s
are gold-sputtered, IMO it might be a good idea to install some better
VHF parasitic-oscillation suppressors - as well as glitch protection - so
that the new 8873s don't suffer the same fate as the old ones.
>Can other tubes be used in this construction?
Not unless they are high-Mu conduction-cooled triodes. I know of no such
animal other than the 8873.
>Have seen in
>an Eimac catalog that theese tubes
>are rated 200W, but my friend told me that the amplifier would easily do 1
>KW output...
>
Only in SSB voice service (if the mfg. ratings are observed). Key-down,
the input P must be reduced to 70% of the SSB voice rating.
...
>Also he told me that this version has roller-inductor in the output
>network, so that you can work all the
>HF-bands including WARC. What is the reliability of such a system compared
>to a switched coil.
>
With a roller-inductor, you need to know where to set the L in order to
obtain the right Q for the operating frequency. However, for general
coverage, many tuned input circuits are needed with a cathode-driven
amplifier.
Rich---
R. L. Measures, 805-386-3734, AG6K
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