[AMRadio] Re: Need ID Help for 1930's Transmitter

Donald Chester k4kyv at hotmail.com
Thu Sep 14 14:00:08 EDT 2006

The 250TH  looks very much like an 806, and as I recall, the filament 
voltage is the same.  It would be easy enough to fabricate pin adaptors if 
you can't find some commercially made ones.  Eimac made two versions of the 
100T, 250T and 450T series, some of which had smaller (807 size) caps and 
others, that had simple pins coming through the glass.  In fact, some of the 
new-in-the-box Eimac tubes I have seen with caps, used caps that were 
attached over the pins with setscrews, and could be removed to accomodate 
pin connectors as needed.

I think a 250TH would be much closer to the original than a graphite plate 
bottle like the 810.  Hovever, I prefer the bottle style of tube, since they 
seem to be more durable.  Of the 806/250T/H-K style tubes, I have found a 
much higher percentage of duds, even with N.O.S. tubes, than with graphite 
plate tubes.

Don k4kyv


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