[AMPS] SB-220 cooling

[2]

>
>Well, I resoldered the pin yet again and thoroughly polished the filament
>pins, and so far the repair seems to be holding.  The socket seems to be
>reasonably tight on the filament pins, so I hope it's not socket
>replacement time yet.
>
To tighten the clip spring, slide it off, bend a bit, and snap it back 
on.  Even though a socket feels tight when unplugging/plugging a tube, 
one pin could still be not tight.  A good way to check a socket for 
tightness is with a single 3-500Z pin soldered to 4 or so inches of #10 
Cu wire, one pin at a time. 
 , 
>This raises a question, though -- I had assumed that the main source of the
>heat that melts the pins was heat dissipated inside the tube element.  Now
>I'm wondering whether it may not be simple resistive heating from imperfect
>contact between the pins and the socket.  Anyone have a view on which
>effect predominates?
>
Filament power alone gets pins 1 and 5 hot enough to melt solder, 
sans-forced air cooling.  

>I also notice that my amp seems to breathe a LOT better with the case off
>(but the cage and deflector plate in place, of course.  A foot away from
>the top of the cage I can feel a nice breeze.  Perhaps I should just leave
>it this way (without the outer case) for contest use.  comments? 

Without obstructions, the stock 220 air cooling is enough for all except 
berserko 11m speech processing  --  provided the fan motor is 
periodically oiled.  
>
cheers, Pete

-  R. L. Measures, 805.386.3734, AG6K, www.vcnet.com/measures.  
end


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