[CQ-Contest] Amplifier venting

[Frank Norton KB8XU]

Hi All,

I've been running amps for over 25 years the only one I ever ruined was one 
I tried to "help" the fan/vent system with a squirrel cage.  The onlysafe 
way to keep it cool is to help the venting of the area around the 
amps.  Any added fans and u are changing the cabinet airflow which was 
engineered at the factory.

This of course voids ur warranty in most cases, plus it causes danger to ur 
tubes.  For instance adding duct work to the fan will dramatically change 
the air pressure that the amp is venting against.  If ur positive pressure 
cage on the back can keep up with increased exhaust u might be ok.  If ur 
fan on the back is out of sync in any way with the fan u add--->u smoke ur 
tubes, at least.

I wud strongly recommend improving air circulation around the amps with a 
very quiet fan, it works both summer and winter, and u can turn it up if u 
want to add air blowing on u if u get too hot.  I recommend buying a good 
fan!  Not a value special.

73 es gud luck de Frank KB8XU
At 05:22 PM 9/26/2001 -0400, you wrote:

>I'm in the process of designing a venting system for both of my=20
>amplifiers, each using a pair of 3CX-800's in a SO2R environment.
>
>The reason for doing this is twofold.  Calling CQ continuously for 48
>hours tends to increase the temperature of the amplifier itself, and=20
>running additional cooling should help prolong the life of the tubes
>as well as other components.  The second is to regulate the shack
>temperature.  It seems I'm constantly making runs to open and close
>the basement door that leads to the garage in cold weather, and causing
>the AC to run excessively in the warm weather.
>
>At Dayton this year, I bought three new identical squirrel cage fans. =20
>They move LOTS of air, but are VERY noisy.  My plan is to have an=20
>HVAC company make hoods that would attach directly to the amplifier
>case with double faced tape, right above the exhaust holes for the =
>tubes.
> >From the exhaust I'm planning on using the 4" flexible "tin-foil" type
>ducting run above my drop ceiling, then out to the garage where the fan
>can be mounted.  Hopefully this would dramatically cut down on the=20
>shack noise, having the fan so far away. =20
>
>Any experiences you've had, or ideas that you have would be greatly
>appreciated so I don't end up re-inventing the wheel! :-)
>
>73...Scott
><SNIP>


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