Where to buy heatsink for power amp?

I think this has been answered other times but I was unable to find the post I saw long long time ago.
I need to buy heat sinks in the USA.
I remember that there was a post with very good links to distributors who have several profiles.

Can anybody help here?

I am going to build a heavily class A biased power amp and I would like to get some good efficient heat simnk and build chassis around it for testing.

Thanks.
 
How can a heat sink be worth the money if it is not flat? Was the problem fixed and how distorted were they?

Yes I agree with you! If heat sink is not flat it is almost useless especially if trying to dissipated a ton of heat.
Any minimum imperfection on thermal transfer can lead to troubles.

However I remember a post with distributors that have different profiles, but I can't find it!!
 
A radius of a few metres across the backplate is not a problem if you are fixing devices that are only 20mm wide.
You will be well resourced to be able to measure the out of flatness across 20mm.

Andrew: I don't disagree. The post claimed it was not "flat". That is ambiguous. It was also not clear whether that was an early production run that has since been sorted out. My question is a reasonable one.
 
I recently got about a dozen pieces from this company.

4 pieces were large-ish, 10 inches by 4 inches. The fee to cut them to order for all of those was only $5 (!!!). As mentioned above, not "finished", so the edges of the cut are very (VERY) sharp, and there were a couple uneven bits at the end of the cut (perhaps that was what was referred to in the post above). If doing this by hand, you just need a bit of patience, and some sandpaper to take the sharp edge off. (they do offer custom machining, but I have not tried it)

All perfectly flat, measured with some kind of shop tool while they were being drilled/tapped and machined for me. No issues whatsoever. Exactly as advertised, and shipped very quickly (to me, anyway).

Very happy with the result at the price!
 
They seem to be rather small heatsinks for a class-A amplifier...
The thermal spec of the heatsinks sold on Parts Express is unbelievably optimistic (unless they use the moving air figure and omit to say so). That would be sad...

The HeatSinkUSA 10-inch heatsink is three times the size for the same price... no cool black with rounded corners, of course... ;)
 

tinitus

diyAudio Moderator R.I.P.
2005-11-24 1:47 am
I think this has been answered other times but I was unable to find the post I saw long long time ago.

wow, and you are from Italy, and ask where ... :rolleyes:

fun aside:smash:
ModuShop.it have heatsinks as spareparts;)
300x40x210, 34EUR, +vat
I think they are top quality Fischer from Germany

Fisher have more efficient heatsinks, but would also be more expencive
one with 80mm long fins(i think its SK157...)
or else look at the types with pressed-in fins for even higher effciency

or if its a very big amp with many OPTs, they also have a 400mm wide heatsink
 

discrete

Member
2010-09-11 8:39 pm
Andrew: I don't disagree. The post claimed it was not "flat". That is ambiguous. It was also not clear whether that was an early production run that has since been sorted out. My question is a reasonable one.

I should have been more precise. The backs of the ones I received were slightly concave over the width of the profiles. When laid on a flat surface the center was about 2.5mm in the air. This is on a profile width of about 250mm.
This did not affect performance in my application (using Sil-pad isolators) and is maybe normal for 'raw' extruded profiles. Proper finishing would include milling and some kind of painting/anodizing.

I have also used the Modushop heatsinks. These are much nicer and can be ordered without the standard tapped mounting holes. But these are much more expensive, even before shipping to north America. Sizes and profiles types are also very limited.

The HeatsinkUSA sinks are great, unless you need precise mechanical alignment with the enclosure cover or intermediate heat-sink blocks. They also require some sanding on the edges and corners to remove cutting marks.
 
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wow, and you are from Italy, and ask where ... :rolleyes:

fun aside:smash:
ModuShop.it have heatsinks as spareparts;)
300x40x210, 34EUR, +vat
I think they are top quality Fischer from Germany

Fisher have more efficient heatsinks, but would also be more expencive
one with 80mm long fins(i think its SK157...)
or else look at the types with pressed-in fins for even higher effciency

or if its a very big amp with many OPTs, they also have a 400mm wide heatsink

I live in the states now, so it would be rally impractical for me.
However I am in Italy now for family deal until Sunday.
Not sure though I want to load on my suitcase extra 30lbs of material.


I am going to host a nearly 200Wclass a power amp so I need something pretty good.
Space is not a constraint here as I am building the chassis around the heat sink.
However I would like the slabs of material to line up pretty precisely without too much extra work.
 
................................ The backs of the ones I received were slightly concave over the width of the profiles. When laid on a flat surface the center was about 2.5mm in the air. This is on a profile width of about 250mm.
that is bad. How did heatsink USA react when you told them?
This did not affect performance in my application (using Sil-pad isolators) and is maybe normal for 'raw' extruded profiles. Proper finishing would include milling and some kind of painting/anodizing.
You should not have to mill them. Mechanically they should line up with the other chassis components.

Thermally, the curve has almost no effect.
 
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Try Conrads at Conrad Heatsinks

They are Australian but ship world wide, I think they have an outlet or two in the US, they are well engineered, very large range, good spec sheets and they are die cast, machined and linished. Most importantly the fins are vertical for efficient convection.

Yeah but shipping to the us will be extremely expensive!!

I a looking fora distributor that stocks Fischer sk538 or sk539.
Length is 600-650mm respectively and fins are vertical as well with excellent thermal resistance.
I need two blocks of this per side per mono block to handle the amount of class A I am going to burn in.

Ay hint where I can buy these parts?

I will also check with the link you posted but I bet that 15-20lbs of material from Australia will cost a ton off money and might make it not worth it.