J999w ) writes:
Weren't the "TO" keyers popular in those days? I believe it was so popular that
Hallicrafters made them for a while.

jw
K9RZZ
(not that old)

That would have been my guess, because it made such a splash that it
would seem to have been common.

Oddly, though, I don't see it in the 1961 Handbook, though I would have
expected it. By 1968, the next one I have, it's gone solid state. There
is an IC version of the '9TO keyer, and I know I've seen plenty of
references to it, but unless I start digging I can't tell what tube
lineup the original used.

On the other hand, the IC version seems to suggest more than a couple
of tubes. There are a couple of flip flops, and you'd need a dual
triode for each one.

The 1961 Handbook shows a simple keyer, with a 12AU7 as the "clock"
and rectifier, and another 12AU7 for the rest of the keyer. A relay
actually keys the transmitter. That seems to be closer to the level
of the keyer the original poster is asking about.

Michael VE2BVW