Heatsink question

[kheldar]

I have piles of unused heatsinks for Pentium 4's through work. For anyone who doesn't know they are about 4"x5"x3" and usualy have a 3/4" thick base for spreading the heat.

Question is, would one of these be enough to keep a chip amp cool? And what do you guys think the maximum power rating for one would be?

Both questions are assuming the fans have been removed and are passively cooling the chips.


thanks

 

[needtubes]

I would say that would be adequate... I built a GC for a friend and just used a 1"x6"x1/8" piece of aluminum for each chip. The "heatsinks" get warm, but are never really hot.

 

[Joshua Layne]

I second the other comment.

I am planning to mount two chips to a single P3 copper heatsink. If you are worried about it, mounting the heatsink vertical will allow for better cooling (but you then have to make sure it doesn't rest on the chip (standoffs or something)

HTH.
j.

 

[kheldar]

Thanks for the response guys, I just wanted to check before I spent the time building it just to find i have to rebuild it due to heat...

 

[jackinnj]

I have piles of unused heatsinks for Pentium 4's through work. For anyone who doesn't know they are about 4"x5"x3" and usualy have a 3/4" thick base for spreading the heat.

the "overclockers" have some websites which attempt to get at the thermal transfer characteristics of various Pentium heat sinks. They use Peltier junctions and RadioShackthermometers to calculate the transfer stats.

you can go to the AavidThermalloy or Wakefield websites and get some idea of how the transfer characteristics are determined from the surface area of the sink. On-Semi has a good apnote on Thermal management. National has specific recommendations for heat sinks for the 3875/3886 etc -- just parse through their search engine using "Overture" as a starting point.

oh, to put it simply, I think you could run a 3875 full blast with one of those big P4 sinks.

Jack

 

[lgreen]

heat sinks

I have never opened a pentium, but I suspect I might be using those heatsinks. If this is in fact true, they are great for a GC. Check out my other posts.

For example see this thread.
http://www.diyaudio.com/forums/showthread.php?postid=292577#post292577

and this one.
http://www.diyaudio.com/forums/showthread.php?postid=301128#post301128

I have found that into a 5 ohm resistor these sinks get hot, but into a real speaker, they do not get that bad at all. Have at it and good luck. Mine sounds great.

 

[azira]

P4s I think can burn up to 60W of heat. I bet using the fan you could cool a Zen with one of these heat sinks... actually I might try this some day. But passively cooled, the fins are pretty close together. I imagine it should do just fine however for a GC, their cooling demands aren't so great.

 

[jackinnj]

by the way, in my high voltage MOSFET power supply I am using a Sunon fan purloined from a P3 -- it is absolutely dead quiet. You can dramatically benefit the "wicking" of heat with a small 12 VDC fan like this (most PC fans are pretty noisy, however.)

 

[elizard]

i'm using a p1 (or p2, not sure) heatsink that's 2"x2"x1.5" and it only gets warm, although i only run it at about 1/4 volume (live in an apartment). i'm sure they'll be fine