For those on the list that have them, see Bill Orr's "The Radio Handbook" 14th
edition, pages 580 through 583 - 'A 4-1000 Pi-Network Amplifier'. (I'll bet
Carl has one)
The glass chimney is not specified and neither is the socket - just a "special
air socket".
Note the concave top directing forced air cooling across the anode connector.
Mid-1980s I needed a Coleman lantern chimney and found a replacement in a small
hardware store. The owner offered me his entire obsolete stock of Coleman
chimneys (all 4 of them) for NZ$10. The largest one was identical to the one
used in Bill Orr's amp.
(I gave it to a friend for his 4-1000 amp project.)
If I needed that 'Pyrex' chimney now, I would look for those big Coleman
lanterns in small-town antique stores before the owners realise that the
chimney is worth more than the lantern.<G>
73, Ken ZL1AIH
None these make a really good replacement for a glass chimney for what
should be obvious reasons. The glass transmits radiant energy freely.
Silicone rubber and fiberglass both absorb this energy almost as
readily. That means they need a wider spacing from the tube envelope and
more air to keep the new chimney cool. How well the forced air cools
the chimney remains to be seen, but fiberglass, silastic rubber (TM) and
even ceramic used on a glass tube is an entirely different proposition
compared to using them on external anode/metal tubes.
I think the earlier suggestion make by some one to use cut large glass
jars such as pickle jars is probably both the best and cheapest approach
although it does take a bit of practice to make a good one. Done with
care you can get the straight sides and slight curve in at the top to
cool the anode seal..
73
Roger (K8RI)
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|