Very true Roger! I built a 6C21 160M amp back when I was still using
the stock NCL-2000; drove it with a 100V (factory 160 option) and later
a T4XC. Tube was a NIB Matchlett and must have been $10 tops otherwise I
wouldnt have picked it up at a hamfest!
What I REALLY want are a pair of good 750TL/TH's, 1000T, HK-1054 or
HK-1254.
Im assembling a pair of HK-354's to go with the pre WW-II Hallicrafters
HT-9 recently restored.
Carl
KM1H
----- Original Message -----
From: "Roger" <sub1@rogerhalstead.com>
Cc: <amps@contesting.com>
Sent: Monday, January 19, 2009 10:42 PM
Subject: Re: [Amps] Plate bypass caps
>
>
> 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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>>
>>
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