Needle headsink

[GeDeon]

Kind time of day by all!
I am sorry for mine English - composed by the interpreter.
At me a question about headsinks. The large enough ridge headsink to me are to be put no, I shall do it only as a last resort. As far as more effectively needle headsink? You see there is an opportunity to make the good case with needle headsink. I heard, that they on 70-100 percents more effectively ridge at same dimension - not so I understand about what speech goes = /
Answer please, as far as is urgent to put them?

[nemestra]

Originally posted by GeDeon
I heard, that they on 70-100 percents more effectively ridge at same dimension

'Needle' or pin fin heatsinks are only more effective if force cooled. That why in personal computer applications they are used with a fan on top of the heatsink. For normal amplifier applications where the heatsink is cooled by natural air flow only 'ridge' heatsinks are far more effective and pin fin heatsinks are worse. Most people building amplifiers are not willing to use fans due to the noise. This can sometimes be overcome by slowing the fan's rotation speed.

For low dissipation applications, for example, LM3875 amplifiers, pin fin heatsinks may be ok. However, you have posted in the Pass Labs forum so I assume you need to dissipate a lot of power.

A good read is 'Hot Air Rises and Heat Sinks' by Tony Kordyban, ASME Press, ISBN 0-7918-0074-1. In chapter 6 (and other places) he explains why pin fin heat sinks aren't a universal cure.

James

[GeDeon]

Thank for the fast answer! I shall try to find this book and read!