Carl wrote:
> Its even more fun when you are playing with Class C AM; a mode I have
> been enjoying lately again. Above a certain value you are beginning to
> shunt the audio riding on the DC (on both sides of the choke btw) and
> start sounding like the space shuttle.
>
> There is nothing more relaxing on a winter day than watching 304TL's
> modulating 250TH's.
>
Ah, come on Carl. If you like that glow, get a pair of 6C21s<:-)) They
drive with no more than a slight breeze, and are a real challenge to
neutralize on more than 3 bands at a time. I think the cathode emission
is something like 30 Amps although they are somewhat limited by that 600
watt, tungsten anode. And to think, I used tog et them for $5 each.
"Long time ago", I used a single 6C21 on 80-20 for a short time before
replacing it with a pair of 813s in GG. The grid used a bundle of
large, carbon resistors that pretty much served as a dummy load with the
voltage driving the tube. On my first transmission I forgot to turn the
gain back down on the HT-37. It didn't melt a hole in the plate, it
blew a hole in it. The tube was just setting there when all of a sudden
(and on the first syllable I think) about a third of the plate just
disappeared. The 800 ma plate meter hit the pin so hard I had to take
it apart to get it to work again.
I stuck in another 6C21, made sure to start with the mike gain at zero
and it worked quite well. Of course I have no idea as to the IM figures,
but my guess is they weren't all that good. I do know that another ham
lived 4 houses down and across the street from us. When I used the amp
on 40 he couldn't operate on 40, so I tried to stay on the other bands
when he was home.
73
Roger (K8RI)
> Ceramic tubes take all the "romance" out of QRO.
>
> Carl
> KM1H
>
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