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Old 27th January 2013, 07:22 PM   #31
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Location: Fosser, Aurskog-Holand, Akershus, Norway.
Quote:
Originally Posted by EUVL View Post
> 60 hot heatsink is a sure way to degrade lifetime for ALL components in an Amp.
> Regardless wich class.

That I do not agree, and I have explained that in detail in the article.
Above all if you just look at heat sink temperature, and ignore the thermal path all the way to the semiconductor substrate, you may well come to the wrong conclusions.
It is in the end the junction temperature that is of critical importance, and the Toshiba reliability handbook has illustrated this clearly and scientifically.

I do agree that lower operating temperatures is always beneficial.
But the benefits have diminishing returns at some point.
So my personal design guideline is still <=100C junction temperature.
And this is much more meaningful than defining heat sink temperature.
You can start discussing where the heat sink temperature should be measured ....


But that is only my personal opinion,
Patrick


Wich very often ends up with keeping the heatsink temp lower than 60'C
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Old 27th January 2013, 08:14 PM   #32
sreten is online now sreten  United Kingdom
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Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally Posted by counter culture View Post
A class A amp runs cooler when there is music playing.
Anybody else?
Hi,

No it doesn't in reality in any meaningful way.

The dynamics of music and the fact most people don't listen at clipping
levels, usually -6dB to -10dB below that should be your normal level if
your amplifier is wisely chosen to match your system, means the drop
of dissipation is very low, and is hardly what one would call "cooler".

There is more misinformation in your statement than the real fact.

Which is course is true. If you have a class A amplifier you will never
notice. It will never appear to run cooler unless you put full power
continuous sine waves through it, which are no fun to listen to.

(Or ply it with one of those hideous no dynamic range CD's at
full power, but then what would be the point of a class A amp ?)

rgds, sreten.
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Last edited by sreten; 27th January 2013 at 08:26 PM.
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