[Amps] Using computer CPU coolers on GI46b triode ?

[Jeff Blaine via Amps]

The CPUL cooler used as a heatspreader with an external fan may work.  You 
can test it by running the amp for a bit and using a non-contact IR to 
measure the tube at the interface between the cooler and the tube.  Try to 
keep that below 200C if you can manage it.

I run heat spreaders made from some heatsink material that was cut and 
machined for the purpose.  Started out with huge dual blocks that really 
sucked the heat our of the GI7B.  The problem was the parasitic cap was so 
high it made for a tough pi-net configuration given the spacings available. 
Ended up cutting further back a couple of times to address the parasitcs. 
And amazingly enough, the tube temp did not rise much leading me to conclude 
that even in the smaller configuration there was enough air flow and cooler 
surface area to keep the tubes from overheating even at 350W Pd.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message----- 
From: Carl
Sent: Saturday, May 10, 2014 8:35 PM
To: Steve Gorecki VE3RX ; amps at contesting.com
Subject: Re: [Amps] Using computer CPU coolers on GI46b triode ?

I doubt if anyone was considering using the dinky little CPU fan.

A heatsink in my hand from an ancient 800 MHz Celeron is 3 x 2.5 x 1" with
25 fins. Using a 4.5" standard size muffin fan blowing transverse thru the
fins it will move a lot of heat. I'll leave it to those with more time on
their hands to compute all the variables.

Ive been up since 05:30 and off to bed.

Carl
KM1H


----- Original Message ----- 
From: "Steve Gorecki VE3RX" <ve3cwj at gmail.com>
To: <amps at contesting.com>
Sent: Friday, May 09, 2014 3:53 PM
Subject: Re: [Amps] Using computer CPU coolers on GI46b triode ?


> Speaking from the CPU side of things, most CPU coolers cool a CPU that
> gives off about 65-135W of heat. Usually not any more than that. Thus,
> depending on the tube dissipation, you would need several CPU coolers. 
> Even
> if you used a CPU water cooled cooler, they are still rated at about
> 125-150W maximum.
>
> I just don't see how a CPU heatsink and CPU fan can cool a GI46b at full
> power... However that said, a tube can run a lot hotter than any CPU can,
> maybe double the temperature. Taking that into consideration, maybe a CPU
> cooler can dissipate 250W of heat when running at tube temperatures...
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