I have a couple of 8025A's to use for something different....like PP
modulators or a hi-fi amp.
Carl
KM1H
----- Original Message -----
From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
To: "Barrie Smith" <barrie@centric.net>; <amps@contesting.com>
Sent: Sunday, August 15, 2010 3:36 PM
Subject: Re: [Amps] Glass tube plate color
>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@contesting.com [amps-bounces@contesting.com] On Behalf
> Of Barrie Smith [barrie@centric.net]
> Sent: Sunday, August 15, 2010 2:16 PM
> To: amps@contesting.com
> Subject: Re: [Amps] Glass tube plate color
>
> Bill, some answers below.
> ----- Original Message -----
> From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
> To: "Barrie Smith" <barrie@centric.net>; <amps@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@contesting.com [amps-bounces@contesting.com] On Behalf
> Of
> Barrie Smith [barrie@centric.net]
> Sent: Sunday, August 15, 2010 12:52 PM
> To: amps@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@jeremy.mv.com>
> To: "Barrie Smith" <barrie@centric.net>; <amps@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@centric.net>
>> To: <amps@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@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>>
>
>
>
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