[Boatanchors] General question on substitutions

[Sandy W5TVW]

The 12BY7 was replaced in later models of the 100V.  The 12BY7 wasn't quite 
up to the job it was being asked to do as I recall.  I cannot for the life 
of me remember what the "sub" was.  There is a chap named Nick Tusa who 
specializes in Central Electronics 100V and 200V rigs and also the 600L 
amplifiers.  Do a name lookup on QRZ.com and I'm sure you will find him. 
When you do, e-mail ham and he should be able to give you the rundown on the 
changes made to the 100V transmitters.

73,
Sandy W5TVW
----- Original Message ----- 
From: "Eugene Hertz" <ehertz at tcaf.org>
To: <boatanchors at mailman.qth.net>
Sent: Wednesday, January 17, 2007 12:23 PM
Subject: [Boatanchors] General question on substitutions


>I am investigating a problem in my central electronics 100V transmitter. I 
>*think* the problem is with the first mixer which is a 12BY7. I began 
>looking to get this tube and noticed there are subtitutions available. 
>Other than the 12BY7A which is a "slow start" version, some websites list 
>substitutions as 12BV7, 12DQ7, 12GN7. However not all websites list all of 
>these as subsitutes for each other.
>
> The GE datasheet for the 12BV7 is the only sheet that directly mentions 
> the 12BY7 saying "In application and characteristics it is related to the 
> 12BY7"
>
> Some sites like NJ7P list a "preferred" substitute as the 12DQ7 and a 
> general substitute (not preferred) as the 12GN7 but does not mention the 
> 12BV7 (again which is mentioned as a "related" tube in the GE datasheet.
>
> So what does it all mean? Am I making much ado about nothing here? Do I 
> just pick whichever I can find in my tube spares and try it? If it works 
> leave well enough alone? Is it possible that one of these is lower noise 
> than the others and could be beneficial? Or any other benefit? (i.e. Oh 
> yes, people stopped using the 12BY7 in favor of the 12xx7 long ago because 
> of its superior properties...)
>
> What sayeth you all tube experts?
> Eugene
>
>
>
>
>
>
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