heatsinks from Australia ?

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I enquired about the MF30-2F-151.5 heatsinks from Conrad Engineering based in Australia. See link from Mark Finnis:


and Julian quoted the shipping costs for 2 of these to USA by seamail to be US$28. I was just wondering if there are any Aussies traveling to the States who would be kind enough to help us American residents purchase some of these?

Alternatively, does anyone know where I can order similar heatsinks from an American source?

Thanks for your help,
Group purchase

I trade internationally a bit, and I can tell you the max weight for any parcel via post in or out of Australia is 20kg. So a volume purchase would need to be sent via a shipping company, and probably cleared through a Customs agent at your end with all their fees and possible duties to be paid. Get a <b>firm</b> quote in writing before you commit.

Companies like TNT, DHL, Fedex etc can do it too, but sit down when you get the prices. The Australia Post online calculator is available at http://www1.auspost.com.au/pac/ and it is very accurate. I quote from it all the time. Actually Yanks have nit good: the difference between surface and economy air to the US is quite small, but from the US to Australia, the ratio can be 2.5:1 and it takes longer on average to get to Oz.

Oh, good to know. Thanks for the info Brett!

At just over 2kg a piece, my 4 heatsinks will be about 8.5kg, plus packaging. So, there'd be room for another 4, give or take, to stay within the 20kg limit.

Given the cost of other heatsinks, even if the shipping is $14 per heatsink, I think the total cost will still be way lower than just about any other dependable source in NA. Surplus, salvage and auctions are another matter...

In any case, I'll give it some further thought. I'm not sure if it will be cheaper to have a large order shipped to one location, and then send a smaller package domestically to the other person, or if would just be cheaper to have each person's order shipped straight to their address in the first place... guess I'll have to poke around the USPS site and get some rates to find out.
Hi Chad,

I am a personal friend of Julian at Conrad, and know these heatsinks very well. They are excellent for high dissipation amps, but they have a unique feature.

They are pressure cast. This means they can incorporate 3D complex shapes, and the flange on these heatsinks is absolutely ideal for mounting power semiconductors since it forms part of the base of the heatsink and thermal impedance to the cooling fins is minimal.

In terms of ease of use, this is a huge boon, making for vertical fins, and horizontal device mounting, which is ideal for pcb design and strong mechanical attachment.

The cost of shipping is regrettable, but the product is so good that it's worth it. I have not seen cast heatsinks to this configuration in your markets, although of course my view is limited to the net.

I have no financial affiliation with Julian's company, but I do use his heatsinks in all my kitset amplifiers.



conrad heatsinks

Just as a followup, here's Julian's quote:

"Thankyou for your enquiry. Prices for MF30-2F-151.5 heatsinks are (all prices in US$): 1-4 $24.96 ea., 5-49 $20.96 ea., 50+ $18.72 ea. Availability: Stock items. Best prices for freight of 2 x MF30-2F-151.5 I could find are via Australia Post on Express Service (2-5 days- traceable with signatures)) $66.31, Airmail (10 days) $49.32, Ecconomail (4 weeks) $40.55, Seamail (3 months) $27.67. Insurance would be an additional $2.75.(Cost of freight is rather surprising - perhaps you may be able to find a cheaper carrier? parcel dimensions would be apprx. 5.6 kg., 35 x 20 x 20 cm.)
With regards,
Julian Wales."

It sounds like the US/Canadian folks are not going to save much on shipping even with quantities of 5-49. Unless we can find a carrier that has a lower cost. Chad, let us know what you find out with UPS.


AudioFreak said:
This is not the place to use for budget shipping!
LOL. Budget? UPS?

Guys, if you can swing it, use Australia Post, and pay the extra few bucks for insurance. This gets you registration, as well as the services of the investigators AP use who are really good. I've never had any trouble with them paying. I've had one package go missing (when I worked for someone else, none of mine >2000 items) and they paid up the claim promptly, and even rang me later to say they'd found a postie had stolen it and was being charged by the Feds.

BTW, I've never had an item damaged with AP, even some delicate items sent to me that were really badly packed. AP are very good.

Has any one here heard the true pronunciation of UPS? The economy freight is OOPS, airmail is OOOPS, same day is OOOOOOPS. I have a friend that works for UPS, and he says that all packages go to a conveyer that has an eight foot drop at the end, into the sorting bin.

Needless to say, many a package from UPS has come to me rather battered.

Did anyone buy these MF35-151.5 sinks? I found Conrad last week and am considering 4 of them to replace the horizontal-fin sinks on my Monarchy SE-160s, which are biased Class-A to c. 50 Watts. I measured (using a Fluke 80TK temp module) the temperatures in the bottoms of the screwholes in the top of the chassis extrusions, directly above the output transistors.* The range is 135 - 145dF. Should I be obsessing about this to the tune of $300 of cost?

An externally hosted image should be here but it was not working when we last tested it.

I have to ask--why oh why would any amp designer use heatsinks with horizontal fins?

Would better sinks (= lower transistor temps) allow me to increase the bias a bit?

* The holes are barely visible on the far side, above the circuit board.
I wonder why mr.Poon used vertical heatsinks on the sm70 and horizontal on SE-160... Me too.

They look cool though!Why replace them?? See the last line of my original post--to cool the output transistors better so that I can run the bias a little higher...altho mostly it'd be to satisfy my compulsion to have the fins run in the same direction the air flows around the sinks.
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