[AMRadio] Modulator design needed

Mike Dorworth, K4XM k4xm at arczip.com
Sun Mar 26 17:04:41 EST 2006

6146.... AB-1, 500 volts, 75 watts, 600 Volts, 95 watts, 750 Volts, 120

I thought the original question was to modulate a Johnson 6N2 which uses a
5894. Usually one uses the same Plate supply for the final as the modulator.
The 6146 gives way too much power for the voltage rating the 6N2 would use,
450-600 Volts. The AB-1 807 or some of the hotter 6L6 versions such as 6L6GC
seem more in the same voltage line to give the power needed.

The Viking II could do the whole job with a Ceramic 4 pole, 2 position
switch as shown in Bill Orr's 14 Edition Handbook (his First) It was mounted
on the rear apron along with a 3 lug terminal strip.

In the older 12th Edition (Editors and Engineers) there is shown a phase
inverter driving 6V6's and also one driving pair 813. A 6C4 in the former
and a pair of 6SJ7's in the later case. On the AM Forum Archives there is a
pair of 4-400's driven in AB-1 by a pair of 2E26. Google N9FOY and click on
modulator. Circuits from 6AQ5, 6V6, 807, 6146, 813, 4-400 all published and
none using driver transformers shows this is an OK way to go for most any
power level.


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