[Amps] Power from Pair of Eimac 4 x 150 a / 7034?

[Colin Lamb]

Collins Radio changed the output tubes in the KWS-1 from the 4X150 to 
the 4X250B and there were enough differences that a service bulletin was 
required.  They noted that the input capacitance decreased when the 
ceramic 4X250B came out (which I believe was then called 4CX250B).  I 
think it was either SB 5 or SB 6  for the KWS-1.  The Service Bulletin 
mentions 4X150 (not the A) and notes that there were both glass and 
ceramic 4X250B tubes, with different input capacitance.

73,  Colin  K7FM




On 12/28/2014 1:34 PM, Fuqua, Bill L wrote:
>    I suspect when EIMAC came out with the 7034 they wanted to suggest that they were a good replacement for the
> 4X150A. Military particularly wanted to use the same part number when replacing tubes in their radios, and I suspect that
> EIMAC wanted to not only promote the 7034 they wanted to make one tube type rather than 2.
>    There are subtle differences between the two tubes, besides plate dissipation limit. The characteristic curves for the 4X150A does not show any
> area where there is a negative flow of screen current, while this is an obvious issue some times with the 7034 and 4CX250B.
> This could be a problem in some cases when interchanging these tubes. There are other differences, one is that
> when operating the 7034 at 500MHz it does produce the same output power but requires 1/3 the drive power.
>   73
> Bill wa4lav
>
>   
> ________________________________________
> From: Amps [amps-bounces at contesting.com] on behalf of Colin Lamb [k7fm at teleport.com]
> Sent: Sunday, December 28, 2014 8:15 AM
> To: Peter Voelpel; amps at contesting.com
> Subject: Re: [Amps] Power from Pair of Eimac 4 x 150 a / 7034?
>
> "The Eimac data sheet does not confirm that
>
> http://www.r-type.org/pdfs/4x150a.pdf
>
> The RCA 4X150A/7034 data does:
>
> http://pdf1.alldatasheet.com/datasheet-pdf/view/241849/ETC/7034-4X150A.html"
>
>
>
> The RCA data sheet refers to a 4X150A only, which is a different tube than the 4X150A/7034.
>
> 73,  Colin  K7FM
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