>Regarding flywheel effect and restitution of the half cycle in which the
tube doesn't conduct, that's the exact same thing as suppressing the
harmonics. Any low pass filter that achieves good harmonic suppression
will nicely restore the sine waveshape<
True, but one cannot forget the result on IMD - unless the filter is an
absorbtive type, it will reflect the appreciable second harmonic energy back to
the valve anode. If it IS an absorbtive type, it will lose about 50% of the
power.
The OP was talking about an amp for 160m, so the capacitance problem isn't so
bad, but even on that band, 50pF of valve plus stray capacitance will be such
as to give an elliptical load line and thus phase distortion, doing no good for
the IMD performance.
You can get around the capacitance problem in a wide band amplifier by going
to a distributed amplifier, but you use a lot of tubes and the efficiency is
poor.
73
Peter G3RZP
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