Just as a note on your Hughes sample amplifier URL below....
I see no negative DC bias on either the 4CX-250 nor the 4X10. Strange that
it's not there. Bias is OK on the 6146. Would appropriate bias be introduced
via an RF choke at the grid of each tube? Should the 4CX-350 run deep class
A like the 6146? Also, the schematic shows the 4X10 with a grounded
cathode, though it uses a directly heated filament. Would you bypass the
filaments with .01's for the equivalent circuit and still have the
feedback/neutralization work OK? Just want to double check...
I'm trying to scale this down for a 4CX-3000 with the same driver chain.
As a note to Bill..... The 6db manufacturers peak IMD test is very
interesting. I see it used all the time in literature... :-0 I never
realized what they were doing.
Much like the old F-B antenna specs.
Yes, I will put together a two tone set up and get some real numbers, though
I am convinced that the FT-1000D 10mW tap is going to be usable at this
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