r-theta???
What about r-theta? This is Trigon's Aleph. In this case they are 11" X 11"
http://www.diyaudio.com/forums/showthread.php?postid=239397#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
What about r-theta? This is Trigon's Aleph. In this case they are 11" X 11"
http://www.diyaudio.com/forums/showthread.php?postid=239397#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
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?
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?
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
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
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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
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
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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
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
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Hey Matthew,
I was just doing the same calculations... If a 12"w piece 8" high is rated at 0.18c/w, adding 50% to the width should also add 50% to the dissipation rating.
So, KL-273 at 8" should provide 0.12c/w. I remember Nelson remarking that the Aleph-2 needs 0.06c/w per mono, so two of the KL-273 at 8" looks like a better match to an Aleph-2 or even an Aleph-X mono at 100w.
It looks like there may be enough interest in both kl-271 and kl-273. At this point, I am now more interested in the 273 profile, for both the deeper chassis and the higher dissipation that it will provide...
By the way, thanks for the matched mosfets!
Eric
I was just doing the same calculations... If a 12"w piece 8" high is rated at 0.18c/w, adding 50% to the width should also add 50% to the dissipation rating.
So, KL-273 at 8" should provide 0.12c/w. I remember Nelson remarking that the Aleph-2 needs 0.06c/w per mono, so two of the KL-273 at 8" looks like a better match to an Aleph-2 or even an Aleph-X mono at 100w.
It looks like there may be enough interest in both kl-271 and kl-273. At this point, I am now more interested in the 273 profile, for both the deeper chassis and the higher dissipation that it will provide...
By the way, thanks for the matched mosfets!
Eric
I agree, the 273 would be better. I like bigger, making bigger chassis for me is much easier b/c then layout is less crammed
glad you like the fets, if you have the capability, please check them and make sure they are well matched, i'm very picky, so they should be at the VERY least sorta close, if not right on.
if not, plug em in and enjoy the sweet music!
later!
-Matthew K. Olson
glad you like the fets, if you have the capability, please check them and make sure they are well matched, i'm very picky, so they should be at the VERY least sorta close, if not right on.
if not, plug em in and enjoy the sweet music!
later!-Matthew K. Olson
Matthew,
Follow the link below graphical performance of the heatsink:
http://www.seifert-electronic.de/images/pics/kl-273d.gif
Follow the link below graphical performance of the heatsink:
http://www.seifert-electronic.de/images/pics/kl-273d.gif
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Gengis:
I'm not sure that I trust those curves from the Seifert web page. I'd rather go by the numbers I received from the distributor. There is a curve for the 271 profile here but it does not match the data I got from my contact at RHM.
Given their chart for the 271, it looks to be rated at just under 0.25c/w for 100mm (4"). The data I got from the distributor (and posted earlier in this thread) indicates that a 6" section of 271 is rated at 0.22c/w. The chart shows somewhat less than 0.125c/w at this same 6" length.
The data from the charts seem to be overly optimisitc and could lead to some surprising results
I have not heard back yet on the volume pricing for the kl-271. I will also ask for similar data for the kl-273 profile.
Eric
I'm not sure that I trust those curves from the Seifert web page. I'd rather go by the numbers I received from the distributor. There is a curve for the 271 profile here but it does not match the data I got from my contact at RHM.
Given their chart for the 271, it looks to be rated at just under 0.25c/w for 100mm (4"). The data I got from the distributor (and posted earlier in this thread) indicates that a 6" section of 271 is rated at 0.22c/w. The chart shows somewhat less than 0.125c/w at this same 6" length.
The data from the charts seem to be overly optimisitc and could lead to some surprising results
I have not heard back yet on the volume pricing for the kl-271. I will also ask for similar data for the kl-273 profile.
Eric
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Heat sink ratings
Thinking about heat sink ratings, I seem to be detecting a trend here...
It seems that you can obtain the theoretical maximum dissipation of the heat sink (given a 25c temperature rise) by dividing 25c by the c/w rating of the sink. The more realistic dissipation figure seems to be about 75% of this resulting theoretical value.
For example, the Aleph2 dissipates 300wpc, which using the quick formula seems to require a theoretical 0.083c/w (300w divided by 25c thermal rise). Derating this to 75% of the theoretical value yeilds 0.0625, which is very close to the 0.06c/w that Nelson says is necessary for the Aleph2.
I found this same derating factor (75%) to fit my a40 amp... Guess this accounts for the error in my first post...
Thinking about heat sink ratings, I seem to be detecting a trend here...
It seems that you can obtain the theoretical maximum dissipation of the heat sink (given a 25c temperature rise) by dividing 25c by the c/w rating of the sink. The more realistic dissipation figure seems to be about 75% of this resulting theoretical value.
For example, the Aleph2 dissipates 300wpc, which using the quick formula seems to require a theoretical 0.083c/w (300w divided by 25c thermal rise). Derating this to 75% of the theoretical value yeilds 0.0625, which is very close to the 0.06c/w that Nelson says is necessary for the Aleph2.
I found this same derating factor (75%) to fit my a40 amp... Guess this accounts for the error in my first post...
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