Geo says;
>The two Collins amps, 30L-1 and 30S-1, are the only units that I've ever seen
>with phase comparator tuning.
The (admittedly partial) circuits that I have for those two amplifiers do not
show a phase comparator for tuning, but an amplitude comparator. When the
loading is correct, there's a definite ratio of input volts to output volts
across the tubes. You can have the 180 ( or 0 degree - depending on circuit)
degree phase shift across the tube, but still have the loading wrong.
It's a really useful gizmo. Also appeared in various Marconi military tx's in
the last 1950's, and in the ARRl handbook in a 3-1000Z amp in 1970.
73
Peter G3RZP
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