[Collins] 75S-3B audio output tube

[Robert Jefferis]

Pete,

 

That sounds like one of the few practical suggestions I've heard on this
subject. I think I'll find one of those shields and repeat the surface
temperature measurement survey I made a while back on a 75S-3. I wonder if
you have actually made any surface temperature measurements with the shield?
I'm referring to the tube socket temperature. I found that the 6BF5 socket
really gets baked over time when compared to the other sockets in the 75S-3.
I have concluded that from a thermal management standpoint the 6BF5 was a
real Thanksgiving (gobble gobble) design choice.

 

Bob KF6BC

 

  _____  

From: collins-bounces at mailman.qth.net
[mailto:collins-bounces at mailman.qth.net] On Behalf Of pete wokoun, sr.
Sent: Saturday, December 13, 2008 1:44 PM
To: collins reflector
Subject: RE: [Collins] 75S-3B audio output tube

 



The best thing you can do for that HOT 6BF5 is to put an IERC 5025B heat
dissipating tube shield on it.  It makes a BIG difference in its
temperature.  The next step:  put a lo-noise muffin fan on top of the rcvr
to pull the heat out.  These fans run at 1800 rpm instead of 3600 and don't
have that characteristic whine to them. 
 

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