Donald Chester wrote:
From: "Brian Carling" <[EMAIL PROTECTED]>
Hey - mount those 6AG7s upside down in cooling oil and you
can run 500 watts to 'em. I wouldn't try it but I am sure
SOMEONE has, LOL!
My very first plate-modulated AM rig back in 1959 used a single 6AQ5
to drive a pair of 807's as class-B triodes with screen and control
grids tied together with 20k resistors, and negative feedback round
the 6AQ5. It would work for a few minutes, and then distortion would
start to creep up. I finally figured out that the 6AQ5 was
overheating and the distortion was due to thermal runaway. I turned
the driver stage, which was haywired on a separate little chassis,
upside down and let the 6AQ5 rest in a jar of water. That kept it
just cool enough to keep away the distortion. But I would, on the
average, overturn the jar of water at least once every time I tried to
use that lashup.
Don K4KYV
John/BXO can confirm this story;
Gene White/WA5ATH(sk) had a plate modulated rig out in his garage, and a
modulation transformer that made the awfulest racket of talk-back, when
modulating the rig. The rig worked well, except for that talk-back.
Someone (probably Otis/SWK) said "maybe opearte with the transformer in
a container of oil". So, Gene did. But (heh) he kept the oil in a
styrofoam ice-chest..
The running, on-air, joke was "...what's the oil-pressure on your
modulator, Gene?"
Mind you, this was also in the days when 'parts was parts' and who
-cared- what something looked like, as long as it worked! Therefore,
several parts were scrapped from rigs that server a different purpose in
their life, and afterwards, such things as meters that indicated
"manifold pressure" were used as current meters, etc... You know how
home-brewers are.
Ah, radio was a lot more fun, back then :-)
--
73 = Best Regards,
-Geoff/W5OMR
