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From: msv@unlinfo.unl.edu (mark vanroojen)
Subject: Re: RCA Rec. man. Missing Tubes?
Date: 6 Jun 1994 16:48:15 GMT

thomas james ronan iii (ron2@midway.uchicago.edu) wrote:
: I have found copies of a 1940's RCA receiving tube manual as well as one that
: is still in binder form with updates as old as 1970.   however, these were
: missing many of the tubes I am interested in learning about:

: KT-88's, EL34's, 6550's, 7591's, 300B's.  I am sure there is a totally
: obvious explanation, and I am just missing it.  Could you help clarify it
: for me?

: Thanks,
: Tom

Well, RCA manuals will only list tubes that RCA produced.  So that 
rules out KT-88s (a British tube made by Genelex and Mullard - or 
perhaps only by Genelex, but labeled as Mullard), and the 300B which 
was a Western Electric tube though Cetron has also made it.  EL34 is a
british designation for the 6CA7 which should be listed.  6550s and 
7591s are late tubes that RCA did make.  Probably the loose-leafed 
binder is not as up to date as it may seem.  RCA did list these in its
regular tube manuals such as the RC29 copyright 1973.  Probably 
earlier copies too, since the 6550 was developed by Tungsol in the 
late 50s and the 7591 came soon thereafter (developed by ?).

Hope this helps!

Mark