[Amps] Weird tubes in an amplifier

[Eddy Swynar]

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