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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