[Amps] 813 Amplifier Article

[Fuqua, Bill L]

I am glad that someone has noticed the difference.

   I have plenty of 4E27As and 4-125A, 6155 etc.
And some 4-65A tubes.  My glass EIMAC collection has every thing from a 15E to 2000T but missing
a 1500T.  An interesting thing is that the 1000T is smaller than a 750TL and is sam size as a 450TL/TH.
However, is has a small metal tube to blow extra air on the filament seal.  I suspect it was intended as 
a relatively easy upgrade for transmitters using 450TH/TL tubes.
  
  73
Bill wa4lav

________________________________________
From: amps-bounces at contesting.com [amps-bounces at contesting.com] On Behalf Of David C. Hallam [dhallam at knology.net]
Sent: Thursday, March 31, 2011 12:19 PM
To: amps at contesting.com
Subject: Re: [Amps] 813 Amplifier Article

Strangely enough, the 4E27 and the 4E27A were two completely different
tubes. The 27 is a tetrode and the 27A is a pentode with greater
dissipation.  They are not interchangeable.  At one time I ran a 4E27A
in a 500W CW transmitter from a design published in a 60's ARRL handbook.

David
KW4DH



On 3/31/2011 12:01 PM, jerryjtb at comcast.net wrote:
> Should anyone be interested I have a new pair of Eimac 4E27 tubes. They were
> stored for at least 25 years.
>
> Jerry W0ZD/3
>
> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
> Behalf Of Carl
> Sent: Thursday, March 31, 2011 10:34 AM
> To: ka4inm at tampabay.rr.com; amps
> Subject: Re: [Amps] 813 Amplifier Article
>
>
> ----- Original Message -----
> From: "Ron Youvan"<ka4inm at tampabay.rr.com>
> To: "amps"<amps at contesting.com>
> Sent: Thursday, March 31, 2011 8:57 AM
> Subject: Re: [Amps] 813 Amplifier Article
>
>
>> Fuqua, Bill L wrote:
>>
>>> I have thought of replacing the 813's with 4E27A's. Has anyone used
>>> 4E27A's in grounded grid.
>>> They are pentodes with 125 watts plate dissipation and wire the filaments
>>> in series since they are 5V.
>>> They should have a nice plate glow to them and go in the same socket.
>>     http://www.tubecollector.org/4e27.htm
>>
>> says the 4E27 has a 75 Watts plate dissipation.
>>    ???  I believe the 4E27 is more rare than 813s.
>> --
>>     Ron  KA4INM - Endless Loop: n.        see Loop, Endless.
>
> I notice 4E27A's being ignored on Fleabay and at hamfests. My only
> experience with them was a couple of 6M AM rigs I built to get some activity
>
> on the band. They sure did glow nice.
>
> The H&K 257B is a 4E27 clone.
>
> If you dont want bands above 20M a couple of 803's can really make some
> power and will take the same socket as the various Eimac 4- and 5- triodes
> and tetrodes.
>
> The 814/VT-154 is a scaled down 813 and generally ignored but 3-4 will be
> heard.
>
> Carl
> KM1H
>
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--
"No man should escape our universities without knowing how little he knows."
J. Robert Oppenheimer

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