> The 807 and the 1625 were identical except for the 12.6 Volt
 > heater of the latter, and its 7-pin base as opposed to 6.3V and
 > 5 pins for the 807. The 6BG6 was the same as the 807 except it
 > had an octal base.
That's right!
 > There were so many variations of the same cathode-grid-plate
 > structure that it's hard to keep track of them all.  There were
 > tubes like the 7581, 5881, 8147 (not sure of that one), 7027-A,
 > even the EL34 was close.
Talked to a guy yesterday morning, who was running a DX-60, and hi-level 
plate modulating it with a pair of EL34's.  Actually, it was the Eico 
Modulator he was using.  I believe that after he gets a scope going down 
there, and clips out all the 'clipping' in the modulator, he'll have a better 
sounding AM rig.  For all he uses it for, mid-morning AM on 75m, local around 
South Texas, it's probably all he'll ever need.
 >  There was an English tube the KT34, too.
Got any idea where I can lay my hands on a pair of KT-88's?
 > Gads, the list is awesome, and frankly they all did just
 > about the same thing with minor differences in ratings, shape,
 > maximum frequency, and so on.
That's what being a ham was all about back then, Bob... and there are still 
some today who do the same thing.  Not all AM is heavy Iron - lot of good 
sounding AM signals have been recently comming from unlikely sources, such as 
the Yeasu FT-1000, with an amp behind it.  Once the output is reduced enough 
there there's enough 'head-room' for the audio to expand in the final, those 
little rigs actually have a pretty decent sound, with the right mic.
 > I used a 5894 in a mobile rig back in 1957; I think I was the first ham to
 > use a transistor power supply in a mobile rig.  I used a pair of Delco 
2N174s
 > with a home wound toroid saturating transformer.  Worked Korea
 > with that thing, about 10 Watts, 10 meter AM.  Great fun!
Look for an increase in AM activity on 10m this cycle.  Normal freq is around 
29 MHz.
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73 = Best Regards                ka5thb@bigfoot.com
-Jeff KA5THB
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