DIY heatsinks

[miguel2]

Hi,

I am in the process of building a ZV4. As an alternative to buy the heatsinks I came across the idea of making my own. The schematics are in the figure below, where it is seen by the front. 3mm aluminium plates are joined with square aluminium tube around 20 mm face. This is all bolted to give a height of 161 mm with 7 plates/tubes. Bottom is stainless steel plate 2mm and top SS 1 mm. The front will be around 7 mm aluminium and the back will be SS 1mm. I did some calculations and each side will be around 0.3 ºC/W for a 400mm deep case, which is sufficient for ZV4. The MOSFETs will be mounted on the plates that go inside the amp.

[Roberto Amato]

The calculations you made, I believe are valid if the structure would be SOLID not bolted. On every plate-to-plate surface contact, the heat transfer increases. The square tubing is also a big problem: heat transfer to fins travels only on tubing walls, too thin to do a proper job. If you want to go ahead, I would at least suggest to use square BARS, not tubing.

ciao,
Roberto

[JBL]

You can also use aluminium sheet stamped togheter with aluminiul spacer between them.
IT would give a kind of sandwich.

One thing is that the block between the sheet will need to be big enough and some thermal coupound must be used but I think that it may work.

...Maybe...

[Peter Daniel]

I'm afraid it will not work. I tried to make heat sink ones too, but it was barely enough for one channel of Zen. The size is 330mm by 90mm. I used 1/2" flat bar between, compound and mounted devices in two places. Even then the center was noticable warmer than the ends. Using square tubing is not acceptable, have to be solid bars, but even then the amount of fins you suggest is low. Also mounting devices in one spot, on fin extension inside, is not a good idea; heat transfer will be very difficult.

I have seen nice heat sinks yesterday in Trading Post for $35. Save yourself trouble and possible disappointment and go with a real thing.

[Tony D.]

Although it has been done before successfully

http://home.earthlink.net/~lotusblossom/

I think that for all the work involved and if aesthetics are a concern then it is worth buying a pair of "real" heatsinks.

I have been on a heatsink quest for some time now and IMO the Conrad sinks being offered by rlim on the Trading Post are an exceptional deal and are a known quantity having been used by mefinnis in his Aleph 5.

Where are you located Miguel?


Tony D.

[lowfi]

i have built the "lottus blossum" sinks for an aleph 5. i used the same design as you have shown, except using 18 large fins per channel. i don't have the equip to measure heat at the device junction, but the sink heat is stable at 55-60 degrees C. the heat is uniform across the entire sinks. However, and this is why i am changing to "made" sinks, I don't like the idea of the many contact points inherent in this design, it doesn't seem as efficient as actual sinks. and the time to build.....man, it took me something like 40 hours to drill all those holes.
i'd think long and hard about doing that again.

two cents for the cause.

cheers!!
Scott

[till]

A cheap solution is to use this:

http://www.kermi.de/cgi-bin/WebObjec....1.0.1.2.6.0.0

[roddyama]

Heres another example of DIY heatsinks from the PassDIY Gallery:

http://www.passdiy.com/gallery/a75-p2.htm

Rodd Yamas***a

[carpenter]

Hi,

I own the "lotusblossom" webpages. Being a carpenter, I have learned a great deal of patience. My design works well, but, it is labor intensive! I like the concept of total DIY in my amplifier projects. The more I can do the more the amplifier feels like an extension of my ego.......

My current chassis is black anodized and has huge fins. It is beautiful. It will house either the Aleph 2 or the Aleph X. I have the pcbs and components for both. When things slow down, this winter, I'll get the projects finished.

My hat's off to those with the patience to complete my design.

John Inlow

[moses]

Peter Daniel, your heatsink would probably have been a lot more effective if you just ran a heatpipe to the individual heatsinks rather then that aluminum bar.