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Re: [Amps] Weird tubes in an amplifier

To: "Fuqua, Bill L" <wlfuqu00@uky.edu>, "MU 4CX250B" <4cx250b@miamioh.edu>
Subject: Re: [Amps] Weird tubes in an amplifier
From: "Carl" <km1h@jeremy.mv.com>
Date: Wed, 29 Jan 2014 17:49:46 -0500
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I also copied that article in CQ maybe? Used 3 of them also with a 10A into the 4 GG modified 1625's that were the in thing for awhile for poor high schoolers.

I have no idea what any of the output powers were or the combined IMD but they did work 80-15M.

Carl
KM1H


----- Original Message ----- From: "Fuqua, Bill L" <wlfuqu00@uky.edu> To: "MU 4CX250B" <4cx250b@miamioh.edu>; "William Turner" <dezrat1242@wildblue.net>
Cc: <amps@contesting.com>
Sent: Wednesday, January 29, 2014 2:22 AM
Subject: Re: [Amps] Weird tubes in an amplifier


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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