North America Heat Sink Group Purchase

[sklimek]

What about r-theta? This is Trigon's Aleph. In this case they are 11" X 11"

http://www.diyaudio.com/forums/showt...397#post239397

I believe there was a group buy awhile back, I don't know how expensive they are.

Also Rob's MM heatsinks look good because of price, looks and they can be configuered.

Stan

[LineSource]

The KL-271 profile and 12" x 8" size looks very good for my application. Anodized aluminum is worth the cost because it will give slightly better thermal performance, age well, and present a more professional appearance. I also like the thick base plate, as this gives good thermal spreading and supports easy drilling and tapping of holes for a simple top and bottom plate.

Can we get test data to verify the 0.18 C/watt thermal resistance?

It would be nice to purchase enough units to get the price ~ $50 plus shipping. Can we get info on price vs. volume, and if they will direct ship partial orders to several individuals?

[Mattyo5]

IMHO 12 wide is fine, 8" tall is a hair short. 12x12 seems like a more round number bigger is better!

-Matthew K. Olson

[gengis]

According to Seifert website, 150mm, 200mm, and 1000mm are the different length for the finished heatsinks.

More area for the Seifert finished heatsink would be wider sections.

I guess if no GP interest in wider sections, then I retract my position of getting in the GP.

[Mattyo5]

http://www.briangt.com/gallery/aleph-mattyo

ok, for my heatsinks that i have, each sink has about 1900 sq inches of surface area. including panels and stuff, i have about 4000 sq inches of heatsink area for monoblock aleph 2's. The heatsinks run at 175 watts each (350 watts per monoblock total) at 120deg F. after about 3 hours.

each heatsink in this group buy has approx 1000 sq inches of surface area. I do not think these are adequate for aleph 2's...just fyi for those planning on doing aleph 2's with these. They might be close...and they'll run hot... but the wider extrusion looks better if everyone plans on actually doing 150 watts + of heat passively from these sinks.

-Matthew K. Olson

[Eric]

Wow! I go away for an afternoon and look what happens! So, it seems safe to say that there is some interest...

Here are some specifics that have been asked about:

Maxhawk:
For comparison, the 11645 profile from M&M only has a rating of 0.8c/w. It would take 5 of these the exceed the 0.18c/w rating of a single kl-271 that is 8" long. Three units of kl-271 would equal the c/w rating of your 12 pieces from M&M and would cost about half as much.

Brian:
Thanks for the links! Some really nice looking amps there!

Gengis:
I will inquire about the 400/440 mm (16") width pieces. I will let you know the pricing when I find out. A slightly deeper chassis may have some benefits. Additionally, it seems that using more width is a more effective way to increase the c/w rating as opposed to using a longer length of the more narrow witdh.

Your offer to get longer lengths and cut it sounds interesting... but would also incur a double shipping price and add costs for anodizing after the fact... I was trying to keep this relatively simple so that people have something to use right away.

Kari:
What length of the kl-271 are you using on your Mini-A? Seems that 2 of these sinks would be more than enough for a Mini-A... What is your rails and bias settings? How much output do you get?

sklimek:
I have a few of the R-theta units from the GP that Peter Daniel put together a few years ago. They are great sinks, but They are 11" by 11" and are rated at 0.27c/w. The KL-271 are just as wide, a little bit shorter, and dissipate about 50% more heat. I was trying to find the smallest heatsinks that would handle the greatest amount of dissipation... Also, the M&M sinks cost almost twice as much for the same dissipation as the Seifert units.

LineSource:
It looks like they will not ship multiple orders to a number of people as Peter was able to arrange with the R-theta GP. This distributor is about 2 hours from my house, so I may end up picking them up in person and mailing them myself I don't think that will be very much fun...

Mattyo5:
12" by 12" are available. The thermal data on the KL-271 profile is as follows:

8" = 0,18 C/W
10" = 0,16 C/W
12" = 0,145 C/W

I am certainly willing to investigating different profiles/lengths, but think we will get the best deal if we can settle on a single profile/length for the GP.

All:
I should hear back today or tomorrow on the price for the KL-271 profile (12" by 8") in quantity. Is there some consensus about a different profile that I should ask about? It seems that using an 8" piece of the KL-273 profile (16" wide) would be preferable to using a longer piece of the KL-271 profile (12" wide).

Let me know!

Eric

[gengis]

I vote for the KL273/200/sw, or part #2730701.

But could you inquire about the cost of the 1000mm or longer pieces?
Thanks.

[Mattyo5]

gengis, i calculate for that piece 16x8... approx 1500 sq inchest of sink area....is this about what you get?

just checking

-Matthew K. Olson

[Eric]

Gengis:
Do you want the 1000mm lengths in kl-271 or kl-273? Minimum orders are 10 pieces...

Maxhawk:
Oops! Looks like I read through the M&M web page too quickly and did not account for the different lengths of the profile you pointed out- my apologies... The price of the M&M sinks is lower, but the quality of the Seifert ones is higher...

Eric

[gengis]

Eric,
Yes, That's pretty close.
With the high heat dissipation of this heatsink, it should be sufficient. Of course, the try test is when running the amp for couple of hours.

KL273.

I plan to use all AL for the case in either case.