[Hammarlund] SP-600 NuvistaPlug & more

[K9FFK]

Al Parker wrote:
> Hi folks,
>    We also have that on The Hammarlund Historian website, in the 
> 'H-Files" section.
> for a "deep link" go to: 
> http://www.hammarlund.info/info/sp-600/tech-bulletin-107/
>    ...snip...
>
> ----- Original Message ----- From: "Kenneth G. Gordon" 
> <kgordon2006 at verizon.net>
> To: "Todd, KA1KAQ" <ka1kaq at gmail.com>
> Cc: "Hammarlund List" <hammarlund at mailman.qth.net>
> Sent: Wednesday, November 07, 2007 4:26 PM
> Subject: Re: [Hammarlund] HQ-129 and 717A mod and SP-600
>
>
>> ...snip...
>> Hee hee! Here you go!
>>
>> <http://www.mines.uidaho.edu/~glowbugs/SP600upgrd.pdf>
>>
>> I see it was originally printed in a military technial manual...
>>
>> Ken W7EKB
>
>
> _______________________________________________
> List Administrator: Duane Fischer W8DBF
> ** For Assistance: dfischer at usol.com **
> ----
> http://mailman.qth.net/mailman/listinfo/hammarlund
>
Has anyone ever looked at this schematic and asked why there is a 50pf 
(fifty) on the output (pin 5)?
The 6BA6 Cout (shielded) is given as 5.5pf. The 6CW4/6DS4 Cout is given 
as 1.8pf.
The difference is 3.7pf. So a replacement would need an additional 3.7 
pf on pin 5 (5pf is close enough).
I've looked at my Nuvistaplug and indeed there is a 50pf on the output. Why?
Would/does this not seriously detune the tuned circuit? It certainly is 
quieter!
What gives?

Dick K9FFK