Thread: Power MOSFETs
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Old 11th May 2019, 4:45 pm   #6
McMurdo
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Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
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Default Re: Power MOSFETs

Interesting problem. They're used ever such alot in high power audio, bass guitar amps, PA amps, etc. I dont like those silicone based pads, prefer mica with heatsink compound, I believe it has much lower thermal resistance than the squidgy ones, and you can get them alot tighter without punching through.

Any chance something's going 'RF'? 1600Hz doesn't seem much compared to pro audio which are often specc'ed upto 25khz but some parasitic rf might couple to the heatsink somehow through the washers, I've heard about it before. I dont think there's any intrinsic problem with the IR devices or we'd have heard about it by now. Cloud Electronics for example use them, Ampeg, Mackie, just a few that spring to mind.

An EBB amp (smaller version of that) spends every day powered up inside one of my PC monitor speakers, I did have an initial problem with hum and oscillation until I got the input tweaked/filtered....I posted the problem on here a few years ago,
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