YC-156 Ep Max rating. Look at EIMAC book "Care and Feeding of POWER GRID
TUBES", page 142, section 6.11.1 Maximum Tube Ratings. This is how EIMAC
spec'd their tubes. Quote: "In general, the tube ratings are so chosen
that operation within the ratings will give a minimum of 1000 hours of
guaranteed life."
So a YC-156 at 6500 Ep, assuming 60% efficiency to get 1500Wout, would be
Ip=0.384A for 2500Win. This to stay within the speed limit. However,
operating characteristics are defined by the operator; just keep em' SAFE,
CLEAN, and stable.
Personally I would go for lower voltage, say 5KV, as the higher voltages
require extra $$ for parts and extra precautions. Even at 4KV the YC-156
would be loafing at Ip=2.0A, though maybe a bit more difficult to drive at
lower Ep. Operator defined characteristics. And NO I do not have one of
these tubes operational, (small print YET). Just enjoy this HOBBY a great
deal since first QSO in Jan 1958.
Have fun building amps folks. Do not forget BIG antennas also (but that's
topic for other reflector).
73 de Arne N7KA
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