[Amps] Glass tube plate color

[Fuqua, Bill L]

I actually picked up an ole man's project at Dayton that used a pair of these.
They were cheap subsutute for 250TL tubes. I always thought they were neat tubes.
Only one neater that would glow white hot in operation was the 8012 triodes a skinny long oscillator tube with stranded filament leads and 4 pins out the sides. Also the 316A tubes door knob tube. But less plate dissipations. Never seen these used in amplifiers but they were use as oscillators up to around 500MHz in early WWII.

73
Bill 
________________________________________
From: amps-bounces at contesting.com [amps-bounces at contesting.com] On Behalf Of Barrie Smith [barrie at centric.net]
Sent: Sunday, August 15, 2010 2:16 PM
To: amps at contesting.com
Subject: Re: [Amps] Glass tube plate color

Bill, some answers below.
----- Original Message -----
From: "Fuqua, Bill L" <wlfuqu00 at uky.edu>
To: "Barrie Smith" <barrie at centric.net>; <amps at contesting.com>
Sent: Sunday, August 15, 2010 11:10 AM
Subject: RE: [Amps] Glass tube plate color


  These tubes were never intended to be used as amplifier

**Perhaps they were never intended to be used in amplifiers, but they do
work well in class C service.

This rig is just a lark, something fun to build and use on 10 and 15M AM.  I
had a buddy, Scott, W7TLZ, in junior high school, who's father, a ham, built
him a 40M CW rig with a pair of them.  That stuck in my craw for close to 60
years.  I lucked into several of the tubes free a couple of years ago and
have now built the RF deck.

 but in stripline oscillators, either single tube or push-pull.
There were no real efforts to match them. In oscillators you want low mu so
that they will draw lots of plate current to
get started quickly. I seem to recall the plate dissipation was 200 Watts

** The tube is a cross between the 100TL and the 250TL.  The plate is 100
watts dissapation, from the 100TL.  The grid and filament are from the
250TL.

 with a very bright glow.  These tubes were driven hard is early
radar and radar jammers.  Often pulsed. Hams used to use them because they
were very cheap on the surplus market.
  EIMAC even made a version with a glass tube attached to it (about 1/2" ID)
and no vacuum inside to be used as a ion vacuum guage tube.

73
Bill
________________________________________
From: amps-bounces at contesting.com [amps-bounces at contesting.com] On Behalf Of
Barrie Smith [barrie at centric.net]
Sent: Sunday, August 15, 2010 12:52 PM
To: amps at contesting.com
Subject: Re: [Amps] Glass tube plate color

Damit, Carl, that's a good question!  I'll try that right away.

Barrie

----- Original Message -----
From: "Carl" <km1h at jeremy.mv.com>
To: "Barrie Smith" <barrie at centric.net>; <amps at contesting.com>
Sent: Sunday, August 15, 2010 10:45 AM
Subject: Re: [Amps] Glass tube plate color


> What happens when you swap positions?
>
> Carl
>
>
> ----- Original Message -----
> From: "Barrie Smith" <barrie at centric.net>
> To: <amps at contesting.com>
> Sent: Sunday, August 15, 2010 11:55 AM
> Subject: [Amps] Glass tube plate color
>
>
>> Speaking of class C, I have just completed a nostalgia rig using a
>> push-pull pair of VT-127As (somewhat similar to the 100TL, but looks like
>> a spaceman with grid and plate pins sticking out the sides).
>>
>> I've been bench-testing it the last few days with a wimpy power supply.
>> Surprisingly, I'm up to 500 wattts out with 1300 volts on the plates.
>>
>> I have several tubes, and have tried a couple of different pairs.  In
>> both instances I've noticed that one tube will have a slightly brighter
>> plate glow than the other.
>>
>> I'd like to have the tubes as closely matched as possible.
>>
>> My question is:  Which tube is most likely to be the better, the bright
>> one, or the cooler one?
>>
>> 73,
>> Barrie, W7ALW, DN36au,
>> QRV 6M, 432 & 1296 EME
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
>
>



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