I've known about neutralizing amps for many years, and repaired many of
them for the gov't but I don't recall ever seeing a GG amp neutralized.
Since the plate and cathode ckts. are in phase with each other, and 180
degrees out of phase with the grid, it follows that , directly from plate to
ground one would need a phase inversion. this of course could be done with a
coil and a cap, but it doesn't seem to me that the feedback would remain
exactly what it needs to be on all bands in a bandswitching amp. in the old
days, with grid driven amps, and single band, it seemed to work well, but
today it's a different story. all this is what I learned over the years, and
of course I could be slightly off base or have forgotten my basics(it's been
a looong time) and I was out of the game for nearly 30 years!!!I've recently
repaired some sb200's and one sb220 and the owners are happy with them(and
the amps aren't neutralized), so maybe I haven't totally lost touch with
reality.Any comments?? (I can still learn!!) carl / kz5ca
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