I also ran 4 6AG7s in grounded grid. Slowly conditioned them by raising the
plate voltage to
1kV. My 200 Watt lamp dummy load got quite hot. I tried one first and then got
a large block of
aluminum that I drilled four 1 inch holes into. Then using a carbide saw blade
that my father had
on his table saw, I slotted the block to make fins. I mounted it on a chassis
with a color TV power
transformer and voltage doubler. My filter capacitors were some AC run
capacitors I got from
a scrap pile at a heating and air conditioner shop. I only had a few Watts
drive from my
CE10A. I had bandswitched it since it only came with a 80 meter coil set. So my
output was
not coupling was not ideal.
It worked well from 80 to 20 meters but could not get much output on 15.
I still have the heatsink but can't find the rest of it.
73
Bill wa4lav
________________________________________
From: Amps [amps-bounces@contesting.com] on behalf of MU 4CX250B
[4cx250b@miamioh.edu]
Sent: Wednesday, January 29, 2014 12:00 AM
To: William Turner
Cc: amps@contesting.com
Subject: Re: [Amps] Weird tubes in an amplifier
When I was a kid I built a linear amp running four 6AG7s, from an
article in CQ. The author had discovered that the nominal 3W plate
dissipation of the 6AG7 could be pushed to 100W. The tubes got
so hot the black paint blistered. As I recall, the tube life was
measured in minutes, not hours. (Those were the days when
Burstein-Applebee sold JAN 1625s for $0.25.) I'm sure some of you guys
remember the article!
73,
Jim W8ZR
Sent from my iPhone
> On Jan 28, 2014, at 9:50 PM, William Turner <dezrat1242@wildblue.net> wrote:
>
>
>> On 1/28/2014 7:24 PM, Mark wrote:
>> Just when I thought I had heard of almost every type of tube in an amplifier
>
> Betcha you never saw an amplifier with a 6SJ7 as the final. When I was a
> poverty-stricken teenager, that was what I used on 40 meters. Three watts DC
> input and I worked the east coast from California. I was so proud I almost
> hurt myself smiling.
>
> 73, Bill W6WRT
>
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