> amplifier was basically DAFt, he tarnished himself. // Another example
> is Maxwell's conjugate matching theorem. If it were 100% true, amplifiers
> could be no more than 50% efficient. .
And the logic behind that statement is???
> >For example, Collins had a spotless reputation of good designs,
> >yet they somehow came up with a goofy idea that lifting the grids
> >of a GG triode class AB2 PA with high reactance capacitors added
> >"negative" feedback.
>
> ? To find out who's goofy, take a dipmeter and measure the 811A grid
> resonance in a Collins 30L-1 amplifier. Short the grid to gnd capacitor
> by soldering a strip of copper foil from the grid terminal to ground.
> Remeasure the dip frequency. If the dip frequency decreases with the
> short in place, Collins did not goof.
Or you could measure with the correct instrument and measure
something meaningful like feedthrough power, and see feedthrough
power increases when the capacitors are installed.
It's a bad idea, for a multiband amplifier, to increase unwanted
feedthrough. Especially when the tubes have too much feedback to
be stable without neutralization when the grids are grounded.
73, Tom W8JI
w8ji@contesting.com
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