[AMRadio] Mfg date for 4-400 series

John Lawson jpl15 at panix.com
Fri Mar 23 11:32:49 EST 2007

On Fri, 23 Mar 2007, Bob wrote:

> According to the info that I have, they were in production in 1950.  They 
> were not listed in the 1948 data sheets.  So it could be between 1948 and 
> 1950.
> Hope this helps.

   Actually, this deepens the Mystery - both my HB3s reach from the late 
30s to the early 60s... they were updated by subscription, so it depended 
on who had them as to exactly which updates got posted.

   I have a 1962 TT5 that goes directly from 4-250A to 4-1000, as do the 
HB-3 sets.

   I am lacking RCA transmitting tube data from 1963 - 1971.

   The 4-400 does appear in the 1972 TT5 manual.

   So: if they were made starting in 1950 - why are they not in the data 
books until nearly 15 years later..?

   I'm sure there's a fine answer out there, somewhere.... just one of 
those trivial pusuits to distract one from the day's Business..  ;}



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