After more reading in the Orr book, I discovered a discussion of feed
through power in a cathode driven amplifier.
We have all heard about the drive power adding to the output power. Orr
says, and I am paraphrasing here, that a PORTION of the drive power is added
to the output power. He goes on to say that the greater the ratio of drive
power to the feed through power, the better the imd performance. He further
suggested that the optimum feed through power for best imd performance is
about 10%.
Heck, 10% of a 100w drive level is insignificant and might as well be
ignored.
He did not describe how one goes about attaining the 10% feed through level
and I suspect there is no control of this. Perhaps you get what you get
with a given tube?
He also wrote about the improved imd performance due to the heavy negative
feed back inherent in cathode driven amplifiers compared to grid driven;
often in the 10 to 15 dB range of improvement.
We have always heard this to be so; at least that old saying is correct.
73,
Gerald K5GW
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