modulator heat sink

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modulator heat sink

Postby frank carcia » Sun Feb 10, 2008 9:29 pm

Hi all,
Well the rectifier filter module is done so now it is time for metal work for the PDM modulator. All you QRO boys I have a question. I have a number of heat sink options for the new modulator and wonder how much surface area is good for say the modulator to monkey swing the 20 FET Final. I want to fit the modulator and filter behind a 8 1/4 inch rack panel.
I was thinking of 4 hunks of heat sink with vertical fins across the back of the module with about 1100 square inches of surface area. I figure 200 watts dissipation to make 2 KW of audio. Anybody have any suggestions/ I can double it if necessary. I'm trying to avoid using fans so anybody have an idea of average dissipation of a modulator running AM.
A rig running 375 watts needs what around 500 watts into the modualtor so making 50 watts of steaty state heat.
When you old buzzard anybody have an idea of how much the average dissipation goes up. This is assuming 1500 watts out so maybe peak input to the modulator around 2 KW makong 200 watts of heat. At 200 watts SS that would only be 24 degrees "C" temperature rise but heck voice is a lot less than steady state.
Bottom line how much hotter does your heat sink get when you buzzard compared to carrier only.
The 4 heat sinks will end up 9 inches tall by 16 inches wide with 1 1/2 inch fins I could also do 2 or 3 inch fins of similar size.
frank carcia
Senior Contributer
Posts: 765
Joined: Fri Jan 31, 2003 10:48 am
Location: Enfield Ct. / Niantic Ct.

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