[Amps] Glass tube plate color

[Carl]

You are correct Barrie, the VT-127A was aka the 100TS for "Special" in 
house. Eimac has been mixing up standard parts almost as long as they have 
been in business. The original 150T was a pair of 75T's in one envelope 
which morphed to the 152T and later with four into the famous 304 twins.

These days hams use the YC-156 which is a 3CX15000B7 internals with a 
3CX5000 anode.

A good friend of my dad was a ham who ran a pair of VT-127A's on 20M CW only 
using a pole pig in the 50's. Just keying on CW the plates were almost white 
so Im rather sure he wasnt strictly adhering to the 1000W input 
rule....typical open rack construction. With some air you could probably run 
them safely at or close to 250T specs.

Carl
KM1H



------ Original Message ----- 
From: "Barrie Smith" <barrie at centric.net>
To: <amps at contesting.com>
Sent: Sunday, August 15, 2010 2:16 PM
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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