can anyone shed some light on what is a reasonable heat sink temp for a zen amplifier. i know mr. pass says you should be able to put your hand on it when in operation but id like to know what a maximum safe operating temp would be. im using the irfp9240 and the irfp140 mosfets in the zen. id like to put a temp probe on the sink and see where it stabilizes.
fligti91 said:
Bear in mind that heatsink is cooler than transistor housing (tab). Put your probe directly to tab and see - you can check your transistor datasheet for safe and maximum ratings plus derating curve.
Rule of thumb is 60C (or famous hand test).
Just make sure not to short-circuit transistor tab and screw if using JK or similar temp probe with metal tip.
fligti91 said:
Knowing that you plan to push your devices a bit harder than most, you must take a look at the de-rating curve in the data sheet. I would expect you to need a heatsink temperature around 40 to 45C, too keep your mosfet's alive.
Do the math, figure how much heat you need to get rid of, then see how much heatsinking you need to keep it at 40C.
Magura
I don't know , well dry fingers maybe the reason, I was in the pub that moment, and done this after 15 years.
In the young years all cigg. was choked with naked fingers, and a friend of mine also tried but finished with a water boll on the finger.
Sometimes my soldering iron when I have nothing close to me is also fast cleaned with my left fing. and you can hear a high frequency tone like pssssssssst.
The limit is not same for everyone, in my case that limit of 50 C is u p above 75C with side of a hand.
In the young years all cigg. was choked with naked fingers, and a friend of mine also tried but finished with a water boll on the finger.
Sometimes my soldering iron when I have nothing close to me is also fast cleaned with my left fing. and you can hear a high frequency tone like pssssssssst.
The limit is not same for everyone, in my case that limit of 50 C is u p above 75C with side of a hand.
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