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Today's Topics:
1. Re: Weird tubes in an amplifier (William Turner)
2. Fwd: Re: Weird tubes in an amplifier (Jim Hargrave)
3. Re: Fwd: Re: Weird tubes in an amplifier (Mike McCarthy, W1NR)
4. Re: Weird tubes in an amplifier (Carl)
5. Re: Fwd: Re: Weird tubes in an amplifier (Fuqua, Bill L)
6. Re: Weird tubes in an amplifier (Roger (K8RI))
7. Re: Weird tubes in an amplifier (Carl)
8. Re: Weird tubes in an amplifier (Carl)
9. Re: Weird tubes in an amplifier (Carl)
----------------------------------------------------------------------
Message: 1
Date: Wed, 29 Jan 2014 09:02:06 -0800
From: William Turner <dezrat1242@wildblue.net>
To: amps@contesting.com
Subject: Re: [Amps] Weird tubes in an amplifier
Message-ID: <52E9340E.1070008@wildblue.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
ORIGINAL MESSAGE: (may be snipped)
On 1/29/2014 7:35 AM, k7fm wrote:
The 6AG7 can be used when you build a replica Paraset and cannot find
a metal 6V6. Rewire a couple of pins. It looks and works the same.
The problem is try joining the Paraset Club, if you fess up to using
the 6AG7, your application will be rejected. But, it would have been
denied anyway because I made mine 40 meters only and used a different
power connector.
73, Colin
REPLY:
I hadn't heard of the Paraset, so I did a Google search. Interesting
history:
http://en.wikipedia.org/wiki/Paraset
73, Bill W6WRT
------------------------------
Message: 2
Date: Wed, 29 Jan 2014 15:11:59 -0600
From: Jim Hargrave <w5ifp@gvtc.com>
To: amps@contesting.com
Subject: [Amps] Fwd: Re: Weird tubes in an amplifier
Message-ID: <52E96E9F.9020201@gvtc.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Mark,
The VT4C is a Army designation for the 211 tube. Google it and you get
several hits
I sent you a PDF file.
Jim w5ifp@gvtc.com
On 1/28/2014 9:24 PM, Mark wrote:
Just when I thought I had heard of almost every type of tube in an amplifier, I
talked to a ham that has 2 VT4C's in an older home brew amplifier he has for
sale. It's a really big amplifier. He thinks it puts out about 500 watts. I've
never heard of this tube before. Is it worth getting anything this big for 500
watts? Can anything be substituted in place of these tubes? Its running 866's
for rectification. I haven't seen it yet but may drive an hour to go take a
look. Thanks for any feedback you guys might have on this tube. Appreciate it..
73
Mark
W0NCL
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------------------------------
Message: 3
Date: Wed, 29 Jan 2014 16:43:25 -0500
From: "Mike McCarthy, W1NR" <lists@w1nr.net>
To: amps@contesting.com
Subject: Re: [Amps] Fwd: Re: Weird tubes in an amplifier
Message-ID: <52E975FD.4070601@w1nr.net>
Content-Type: text/plain; charset=us-ascii
I have the carcass of an old mil-surplus AM rig that has 4 of them in it.
You can get audiofools to shell out hundreds of dollars for
those tubes on that e-place. They are popular for building audio amps.
Mike, W1NR
On 01/29/2014 04:11 PM, Jim Hargrave wrote:
Mark,
The VT4C is a Army designation for the 211 tube. Google it and you get
several hits
I sent you a PDF file.
Jim w5ifp@gvtc.com
On 1/28/2014 9:24 PM, Mark wrote:
Just when I thought I had heard of almost every type of tube in an
amplifier, I talked to a ham that has 2 VT4C's in an older home brew
amplifier he has for sale. It's a really big amplifier. He thinks it
puts out about 500 watts. I've never heard of this tube before. Is it
worth getting anything this big for 500 watts? Can anything be
substituted in place of these tubes? Its running 866's for
rectification. I haven't seen it yet but may drive an hour to go take
a look. Thanks for any feedback you guys might have on this tube.
Appreciate it..
73
Mark
W0NCL
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------------------------------
Message: 4
Date: Wed, 29 Jan 2014 16:47:06 -0500
From: "Carl" <km1h@jeremy.mv.com>
To: "Eddy Swynar" <deswynar@xplornet.ca>, <k7fm@teleport.com>
Cc: amps@contesting.com
Subject: Re: [Amps] Weird tubes in an amplifier
Message-ID: <B7DD51BAB0974E9AB8F34BEA7602C80D@computer1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I had a pair of VT-4C's, aka 211 Special, as a self excited oscillator on 80
CW a few years ago, took me 2 1/2 years to confirm DXCC at about 100W out.
The note sounded pretty good once I used regulated DC for filaments and
plate. As a Class C PP amp figure on about 250W max for CW and 200W on AM.
The receivers were a couple of my early 1930's sets such as a SW-58, AGSX,
FB-XA....not exactly high performance!
Carl
KM1H
----- Original Message -----
From: "Eddy Swynar" <deswynar@xplornet.ca>
To: <k7fm@teleport.com>
Cc: <amps@contesting.com>
Sent: Wednesday, January 29, 2014 11:51 AM
Subject: Re: [Amps] Weird tubes in an amplifier
On 2014-01-29, at 12:15 AM, k7fm wrote:
On 01/28/14 7:24 PM, Mark wrote:
Just when I thought I had heard of almost every type of tube in an
amplifier, I talked to a ham that has 2 VT4C's in an older home brew
amplifier he has for sale.
The VT4C is aka the 211. They have 100 watts of plate dissipation each.
Filament is 10 volts at 3.25 amps. Maximum frequency ratings of 15 MHz
(whoops mc for that vintage). They were often obtained surplus from the
BC-375.
My opinion is that they are a terrible tube for a linear amplifier. There
are a number of triodes that can replace it, however these group of
tubes have been bought up by audiophools, who think these triodes put out
better notes than other amplifier devices.
You can substitute a pair of 805 tubes, but they have also increased in
price. It might make a nice AM final amplifier, but may need some work
for a linear. You could trade out the tube sockets and filament
transformer and use almost any triode. Two 572B tubes would work
In short, you can make it work on the low bands - but why?
73, Colin K7FM
Hi Colin,
Those 211 tubes are lusted-after by the vintage radio transmitting crowd,
too. A coupla years ago I built a 2x211 Colpitts self-excited transmitter
for use in one of the Antique Wireless Association events (i.e. "The 1929
QSO Party")...
It sure did have a VERY unique note / tone, bar none...! And it was an
absolute blast to see those big ol' jugs light-up, too...
~73~ de Eddy VE3CUI - VE3XZ
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Message: 5
Date: Wed, 29 Jan 2014 22:20:44 +0000
From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
To: Jim Hargrave <w5ifp@gvtc.com>, "amps@contesting.com"
<amps@contesting.com>
Subject: Re: [Amps] Fwd: Re: Weird tubes in an amplifier
Message-ID:
<B7E8B5B4A202074084E2515A7B10A7F32D69FD56@ex10mb02.ad.uky.edu>
Content-Type: text/plain; charset="us-ascii"
You have to realize that when this amplifier was built power was measured as
plate input power and not output.
These tubes were rated for 225 Watts plate input max in class C each CCS.
So 500 Watts plate input power for a pair is possible. However, max frequency
at full rating was 15MHz
73
Bill wa4lav
________________________________________
From: Amps [amps-bounces@contesting.com] on behalf of Jim Hargrave
[w5ifp@gvtc.com]
Sent: Wednesday, January 29, 2014 4:11 PM
To: amps@contesting.com
Subject: [Amps] Fwd: Re: Weird tubes in an amplifier
Mark,
The VT4C is a Army designation for the 211 tube. Google it and you get
several hits
I sent you a PDF file.
Jim w5ifp@gvtc.com
On 1/28/2014 9:24 PM, Mark wrote:
Just when I thought I had heard of almost every type of tube in an amplifier, I
talked to a ham that has 2 VT4C's in an older home brew amplifier he has for
sale. It's a really big amplifier. He thinks it puts out about 500 watts. I've
never heard of this tube before. Is it worth getting anything this big for 500
watts? Can anything be substituted in place of these tubes? Its running 866's
for rectification. I haven't seen it yet but may drive an hour to go take a
look. Thanks for any feedback you guys might have on this tube. Appreciate it..
73
Mark
W0NCL
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http://lists.contesting.com/mailman/listinfo/amps
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------------------------------
Message: 6
Date: Wed, 29 Jan 2014 17:22:33 -0500
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
To: amps@contesting.com
Subject: Re: [Amps] Weird tubes in an amplifier
Message-ID: <52E97F29.80908@rogerhalstead.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 1/29/2014 4:00 AM, William Turner wrote:
ORIGINAL MESSAGE: (may be snipped)
n 1/28/2014 11:22 PM, Fuqua, Bill L wrote:
I also ran 4 6AG7s in grounded grid.
REPLY:
I never saw one in a TV, but they are an old tube. Often used as an
oscillator. I've seen amps designed with the tubes on the bottom and
set in water. Looked really strange but added greatly to the tubes life.
73
Roger (K8RI)
The 6AG7 was a great tube in its day. Had about the highest
transconductance of any consumer-type tube as I recall. Originally used
as a video output amplifier in early black and white TVs.
73, Bill W6WRT
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Message: 7
Date: Wed, 29 Jan 2014 17:49:41 -0500
From: "Carl" <km1h@jeremy.mv.com>
To: <g8on@fsmail.net>, "Amps" <amps@contesting.com>
Subject: Re: [Amps] Weird tubes in an amplifier
Message-ID: <A1ECE1B24DF444C98C3087312B91EC83@computer1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
QST also rated it as the best tube for a crystal oscillator in the 40's,
especially the low crystal current.
Carl
KM1H
----- Original Message -----
From: "peter chadwick" <g8on@fsmail.net>
To: "William Turner" <dezrat1242@wildblue.net>; "Amps" <amps@contesting.com>
Sent: Wednesday, January 29, 2014 4:53 AM
Subject: Re: [Amps] Weird tubes in an amplifier
Before TV, it was used a lot as the video driver in various WW2 radars.
The Tung Sol data sheet issue 1 is February 1942: it was made by RCA, GE
and Tung-Sol and possibly KenRad. It was also manufactured in the DDR
(Deutsche Demokratischen Republik - Communist East Germany, prefix DM) as
the 6AG& and a 6AG7k, but my German is inadequate to figure the
difference.
A good tube. I seem to have quite a lot of them - need to find a use for
them.
73
Peter G3RZP
========================================
Message Received: Jan 29 2014, 09:00 AM
From: "William Turner" <dezrat1242@wildblue.net>
To: "Amps" <amps@contesting.com>
Cc:
Subject: Re: [Amps] Weird tubes in an amplifier
ORIGINAL MESSAGE: (may be snipped)
n 1/28/2014 11:22 PM, Fuqua, Bill L wrote:
I also ran 4 6AG7s in grounded grid.
REPLY:
The 6AG7 was a great tube in its day. Had about the highest
transconductance of any consumer-type tube as I recall. Originally used
as a video output amplifier in early black and white TVs.
73, Bill W6WRT
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Message: 8
Date: Wed, 29 Jan 2014 17:49:46 -0500
From: "Carl" <km1h@jeremy.mv.com>
To: "Fuqua, Bill L" <wlfuqu00@uky.edu>, "MU 4CX250B"
<4cx250b@miamioh.edu>
Cc: amps@contesting.com
Subject: Re: [Amps] Weird tubes in an amplifier
Message-ID: <056DE2CE0D15425293632C57B217D788@computer1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
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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Message: 9
Date: Wed, 29 Jan 2014 17:49:58 -0500
From: "Carl" <km1h@jeremy.mv.com>
To: <k7fm@teleport.com>, <amps@contesting.com>
Subject: Re: [Amps] Weird tubes in an amplifier
Message-ID: <E897CCF7E6CE482AB06649BEFE4D1588@computer1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
They were designed for Class B audio AND RF and have very low distortion.
However the mu is only 12 so they take a bit of drive.
As a grid driven SSB linear run them as with any other tube that has a 100W
plate dissipation.
Carl
KM1H
----- Original Message -----
From: "k7fm" <k7fm@teleport.com>
To: <amps@contesting.com>
Sent: Wednesday, January 29, 2014 12:15 AM
Subject: Re: [Amps] Weird tubes in an amplifier
On 01/28/14 7:24 PM, Mark wrote:
Just when I thought I had heard of almost every type of tube in an
amplifier, I talked to a ham that has 2 VT4C's in an older home brew
amplifier he has for sale.
The VT4C is aka the 211. They have 100 watts of plate dissipation each.
Filament is 10 volts at 3.25 amps. Maximum frequency ratings of 15 MHz
(whoops mc for that vintage). They were often obtained surplus from the
BC-375.
My opinion is that they are a terrible tube for a linear amplifier. There
are a number of triodes that can replace it, however these group of tubes
have been bought up by audiophools, who think these triodes put out better
notes than other amplifier devices.
You can substitute a pair of 805 tubes, but they have also increased in
price. It might make a nice AM final amplifier, but may need some work
for a linear. You could trade out the tube sockets and filament
transformer and use almost any triode. Two 572B tubes would work
In short, you can make it work on the low bands - but why?
73, Colin K7FM
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Version: 2014.0.4259 / Virus Database: 3681/7042 - Release Date: 01/29/14
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