[Amps] Re: Amps Digest, Vol 13, Issue 52

[David A. Pruett]

I don't think a 3-500Z chimney will work with the 3CX1200A7.  The *sockets* 
are the same, but the chimneys aren't.  Even Eimac recomments a different 
chimney part number use with the 3CX1200.

I would be very leery of using Coleman lantern chimneys with the 
3CX1200.  The Coleman chimneys I have (acquired along with a pair of 
4-400As) are essentially just glass cylinders, with no reduction in 
diameter at the top to direct air at the plate seal.  I suspect these work 
OK with glass tubes by directing the air past the major diameter of the 
envelope, although the plate seals will be left without direct cooling.  In 
the case of the 3CX1200, the chimney is there to force air through the 
cooling fins.  The Coleman chimneys won't do that very well at all.

There may be different Coleman chimneys - I'm just relating what I've seen.

Scrimping on chimneys seems to be poor economy to me when you consider the 
price of tubes.

Dave/K8CC


At 09:36 PM 1/31/04 -0600, W0UN -- John Brosnahan wrote:
>At 04:56 PM 1/31/2004, K3vw at aol.com wrote:
>
>>You can use a 3-500Z chimney with the 3CX1200A7, Ameritron does ! Willy K3VW
>
>So, if the Coleman lantern double mantle chimney works with a 4-400A
>and that is the same size as a 3-500Z and if the 3-500Z chimney
>works on the 3CX1200A7 then it sounds like the Coleman
>lantern double mantle chimney should work with a 3CX1200A7.
>
>Can anyone confirm that this is the case?  Don't know the price of
>the Coleman lantern chimney these days but it used to be a
>relatively inexpensive way to get Pyrex glass for your 4-400As.
>
>Since I have a couple of 3CX1200xx tubes (A7 and Z7) but no
>chimneys this would be a good thing to know.   Except for the
>fact that a clear chimney is a real waste with an external anode
>tube.
>
>--John   W0UN
>
>
>
>
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