>Rich says:
>
>>Broadcast quality amplifiers typically use negative feedback (NFB) to
>>reduce distortion.
>
>Your statements have always been that Class AB2 grounded cathode produced
>unacceptable distortion, with the implication that no circuit techniques
>exist to prevent it.
mixing (discussions about) push-pull audio amplifiers with single-ended
RF amplifiers is hardly cricket.
> Pappenfus et al describe where grid loading can improve IMD.
For the radio, grid-driven with grid current is an SWR shutdown
nightmare.
>> NFB is valuable in AB1,
It also tends to reduce screen/cathode potential during modulation peaks.
> let alone AB2 grounded cathode. Whether it could make
>a bad
>G2DAF (which is basically a AB2 amp) into a good one is another
>matter........generalisations are dangerous. So a grounded cathode AB2 is not
>necessarily bad on IMD as you suggest. I suspect that not all G2DAF circuits
>have to be bad, but it is possibly easier to get them that way than GG.
>
G2DAF is not bad per se. It produces more distortion than the average
g-g amplifier. This is perfectly legal as long as the splatter does not
go out of the ham band.
>
cheers, Peter
>
>
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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