LM3875 heat sink help.

[CJ Paul]

Argh, I had this post all typed up and it wouldn't let me post. I just now found the little "have you searched check box". I need heat sinks for my LM3875. I don't have access to spare parts. I need a place I can go and buy something and use it. I don't care if its an actual heat sink but I need a link and recommendation. This is my first DIY project and I don't have all the secret handshake knowledge of obscure sources of materials that we use for unintended uses etc. to find parts that no one else can get. I just need a heat sink and for this forum to let me post.

[Greg Erskine]

Hi CJ Paul,

Looks like you succeeded in posting. When I had problems posting I used to cut and paste my post in notepad, so I had a backup copy.

These chips don't normally generate that much heat. I personally use 40 x 40 x 3mm aluminium angle for mine and many just use the metal case as a heatsink. A few use a block of copper or similar material. Computer CPU heatsinks are also often used.

Then you could go to you local Electronics shop and buy a real heatsink.

Conrad heatsinks seem to have a good reputation and I use them on my discrete amps.

http://www.conradheatsinks.com/welcome.htm

Hope this points you in the right direction.

regards

[CJ Paul]

Thanks for the reply. I assume 40x40 is the size of the "legs" of the angle iron and 3mm is the thickness? If so, what length do you use for each chip?

[Greg Erskine]

Hi CJ Paul,

I have 2 x 300mm pieces on top of each other. See pictures here: http://www.briangt.com/gallery/nigc-erskine

I have recently increased the number GC modules from 2 to 4 and the 2 pieces of angle now gets quite warm, not hot, after many hours. For testing purposes, I use 1 x 200 mm piece for 2 chips and have never had a problem.

As with everything audio, YMMV because of PSU voltage, speakers used, construction methods and volume. Remember, having too much heatsink is not a problem.

regards

[CJ Paul]

Cool, that should get me started. Thanks!