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Old 16th September 2011, 12:08 AM   #1
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Default Heatsink candidate for Class A?

Sorry, but I could not find a recent Pass Labs thread associated with heatsinks, so here goes.

I recently purchased a pair of fan-shaped aluminum heatsinks on eBay from a U.S. supplier, for $55 + free shipping. They are massive aluminum. The seller quotes a 0.74 degree C/W spec, but I suspect that may be conservative. They may be a little "light" for an F5 build, but you'all may find them useful in other Class A designs. (I know it's probably heatsink "overkill", but I'll be using these in a Class D chipamp.) The mounting surface for the semi-conductors/components is almost mirror-like (very nice construction).

The seller's ad says he has more. Here's the info, if you'all are interested:

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

...and no--the seller isn't my brother or uncle, or cousin......
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Old 16th September 2011, 04:50 AM   #2
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pair for one F5 channel , with plenty of bottom clearance
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Old 16th September 2011, 05:03 AM   #3
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Bottom clearance - no saggy bottoms around here.. A breath of air from a slow fan might make those heat sinks very A-worthy.
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Old 16th September 2011, 10:48 AM   #4
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Originally Posted by Zen Mod View Post
pair for one F5 channel , with plenty of bottom clearance
Hee Hee....he said "bottom clearance" Sorry, my back meds are kick'in in.

Russellc
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Old 16th September 2011, 11:31 AM   #5
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I think someone sold you a polished engine block.
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Old 16th September 2011, 03:54 PM   #6
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Originally Posted by buzzforb View Post
I think someone sold you a polished engine block.
And they're HEAVIER than aluminum cylinder heads, for a small-block Chevrolet....!

P.S.--I'd agree..... with some light forced air movement around these, they ought to be very impressive. I'm using some reduced-speed fans on my F5 (with the large Conrad heatsinks), and my biggest challenge is getting the MOSFETs up to temp......
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Old 16th September 2011, 09:25 PM   #7
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Quote:
Originally Posted by CanAm Man View Post
Sorry, but I could not find a recent Pass Labs thread associated with heatsinks, so here goes.

I recently purchased a pair of fan-shaped aluminum heatsinks on eBay from a U.S. supplier, for $55 + free shipping. They are massive aluminum. The seller quotes a 0.74 degree C/W spec, but I suspect that may be conservative. They may be a little "light" for an F5 build, but you'all may find them useful in other Class A designs. (I know it's probably heatsink "overkill", but I'll be using these in a Class D chipamp.) The mounting surface for the semi-conductors/components is almost mirror-like (very nice construction).

The seller's ad says he has more. Here's the info, if you'all are interested:

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

...and no--the seller isn't my brother or uncle, or cousin......
wow. it looks like massive heatsinks. do you have the dimensions?

EDIT: never mind. i found it. 0,74. maybe. it depends onon the temp of the heatsink. you want 25celsius above ambient?
3pr channal will do it

Last edited by AudioSan; 16th September 2011 at 09:33 PM.
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Old 17th September 2011, 02:33 AM   #8
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Default More info on these heatsinks

From the eBay seller:

I do have many other lengths (up to 6ft) so if you tell me the aproximate size your looking for I can see what I currently have available. If you'd like an exact length I can accomodete that as well but there is a cutting fee that would have to be covered. It's a fee that I have to pay and I'd just pass that amount along. I have several already cut, exactly like you received except for the length, in the 4", 6", 7" and 11" ranges. I'd be happy to give you a good deal on any of them. I also have many other profiles (shapes) in stock so if there is a preference for shorter or wider or whatever; let me know and I can send you a drawing of the closest match. Regarding the power rating, the 0.74 C/W rating was my personal testing. The industry standard for that part is closer to 0.7 C/W.

-------------- I've asked the eBay seller for his "non-eBay" Email address; when I get it, I'll post it for you'all, in case you want further communication with this seller.
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Old 17th September 2011, 02:35 AM   #9
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AudioSan, and all......

The dimensions on these specific heatsinks are a 3-3/8" x 5" base, with fins rising 5-3/8" from the milled surface of the base. These are my actual measurements of my samples.
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Old 17th September 2011, 06:24 PM   #10
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Default Contact info

Jeff, at Machtron. See specifics at the Machtron website.

Seems like a good guy to deal with....... other heatsink options, designs, lengths available from him.

Ken
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