Rich says:
>mixing (discussions about) push-pull audio amplifiers with single-ended
>RF amplifiers is hardly cricket.
No, it's application of tube technology. A tube that will do push-pull AB2 audio
will do parallel or push pull AB2 RF. There's nothing magic in parallel v.
push-pull when tuned tank circuits are used.
>For the radio, grid-driven with grid current is an SWR shutdown
>nightmare.
?????? What has SWR got to do with it? I presume you're assuming a change in
load impedance on the driver. The argument so far assumes that the driver is a
generic radio - that means it provides the same power into whatever load. OK,
that's not the practical case, but that your argument is that ALL grid driven
amplifiers with grid current MUST, under all possible conditions, be bad on IMD.
Now you're trying to get specific. A driver with good regulation of the RF drive
does not get a problem because of varying load - that was part of the original
conditions I set, viz good RF drive regulation and good electrode voltage
regulation on the grid(s) of the tube(s).
>G2DAF is not bad per se. It produces more distortion than the average
>g-g amplifier.
Can you prove mathematically (or otherwise) that is necessarily always the case
with ALL tubes under ALL conditions?
73
Peter G3RZP
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