These heatsinks can be placed face to face and the center channel that is formed is perfect for a standard 4 11/16" muffin fan. They ar rated at 0.28 C/W without airflow each. With airflow Aleph 1.2's may be within reach.
http://www.meci.com/
24.75" Heavy Duty Aluminum Heat Sink
Heavy duty heat sink comes in two lengths. 24.75" long x 7" wide x 3" tall Each has 5/8" holes and a place for our 1800V Phase Control Thysistor (280-0397) Great for big power supplies and amps.
MECI Part Number: 310-0282 Qty:
Price: $29.95
http://www.meci.com/
24.75" Heavy Duty Aluminum Heat Sink
Heavy duty heat sink comes in two lengths. 24.75" long x 7" wide x 3" tall Each has 5/8" holes and a place for our 1800V Phase Control Thysistor (280-0397) Great for big power supplies and amps.
MECI Part Number: 310-0282 Qty:
Price: $29.95
I'm confusing this catalog. They have another 5 1/2" heavy duty heat sink $9.95, but has same description,and both have same pictures. I have e-mail to MECI but no answer. So I no idea is it a good deal?
dshortt9;
If I understand correctly, the heatsink rating given by the Aavid thermalloy website is based on a single point source of heat. If you spread 12 IRFP240's out per sink, I believe you will achieve much better dissipation than the .28 shown.
I think that the 500 watts could be dissipated by two of these without fan cooling.
One 3" section gives a .8 rating. Let's say you were mounting just 8 FETs per sink - we could calculate an aggregate .1 degree per watt for each sink. 250 watts per sink would give a 25 degree rise. This is not a completely accurate assumption because air flow over a 8 single 3" pieces is completely different than over one 24" section. However, I think that we can use the horseshoes and handgreandes principle and say close enough.
Any one out there have the sinks up and running yet? I would
like to know how close the theoretical calcs match up to the real world.
herm
If I understand correctly, the heatsink rating given by the Aavid thermalloy website is based on a single point source of heat. If you spread 12 IRFP240's out per sink, I believe you will achieve much better dissipation than the .28 shown.
I think that the 500 watts could be dissipated by two of these without fan cooling.
One 3" section gives a .8 rating. Let's say you were mounting just 8 FETs per sink - we could calculate an aggregate .1 degree per watt for each sink. 250 watts per sink would give a 25 degree rise. This is not a completely accurate assumption because air flow over a 8 single 3" pieces is completely different than over one 24" section. However, I think that we can use the horseshoes and handgreandes principle and say close enough.
Any one out there have the sinks up and running yet? I would
like to know how close the theoretical calcs match up to the real world.
herm
Heat Sinks
I stock a pair of heat sinks that you can also
slide together and mount a 4 11/16" fan to
also they are drilled for 10 TO-3 devices
and are on my new arrival page at www.apexjr.com
price is $25.00/pair
Steve
Apex Jr
I stock a pair of heat sinks that you can also
slide together and mount a 4 11/16" fan to
also they are drilled for 10 TO-3 devices
and are on my new arrival page at www.apexjr.com
price is $25.00/pair
Steve
Apex Jr
They have another 5 1/2" heavy duty heat sink $9.95
This one is shorter, they used the same picture to show the cross section of the sink. Apex gave me the idea to try them this way and they work. Both are excellent values. C'mon, build those Pass amps! Hmmm... 500 watts no air... Kilowatt Pass X's?
This one is shorter, they used the same picture to show the cross section of the sink. Apex gave me the idea to try them this way and they work. Both are excellent values. C'mon, build those Pass amps! Hmmm... 500 watts no air... Kilowatt Pass X's?
do you think these heatsinks would be adequate for aleph2 monoblocks? cut the 24" ones down to 18" and have 1 per side?
I would just leave them the same size and have two per channel, as you can never have too much heatsinking.
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Brian
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Brian
er, yeah, but thats TOO big. i dont want the thing to look horrible...
so would 18" not be enough cooling? i assume that 1 of these per channel wouldnt be enough either. (if im doing stereo aleph2's, would one per channel be enough?)
i just dont want a component thats 24" deep, thats way too big to fit anywhere.
so would 18" not be enough cooling? i assume that 1 of these per channel wouldnt be enough either. (if im doing stereo aleph2's, would one per channel be enough?)
i just dont want a component thats 24" deep, thats way too big to fit anywhere.
why not cut them in half? and have them per side, standing upp..? that would improve the cooling efficiency by 20%
/micke
/micke
I was thinking of the wrong heatsinks... I was thinking of the other big heatsinks that they used to offer.
Cutting them in half seems like the best plan to me and would provide a better looking chassis.
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Brian
Cutting them in half seems like the best plan to me and would provide a better looking chassis.
--
Brian
but (original question once again), 1 18" section per channel would be enough cooling? vertically or horizontally?
i assume that 2 18" sections per channel is enough also...
i assume that 2 18" sections per channel is enough also...
BrianGT said:
I don't think that one 18" would be enough.
I would instead, cut the heatsink in 3 even pieces, buying 3 heatsinks total, and using 4 of these pieces per channel, orientating the fins vertically.
That would give you 2 chassis that would be ~8" high and 21" deep.
I would then use one of these chassis per channel. You could then mount 3 devices on each of the heat sinks in the big middle part.
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Brian
I would instead, cut the heatsink in 3 even pieces, buying 3 heatsinks total, and using 4 of these pieces per channel, orientating the fins vertically.
That would give you 2 chassis that would be ~8" high and 21" deep.
I would then use one of these chassis per channel. You could then mount 3 devices on each of the heat sinks in the big middle part.
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Brian
Brian:
Do you think a plastic/aluminum blade in a chop saw would work to cut these?
I assume a bandsaw would be best, but I don't have one of those. Table saw and a chop saw I do have, and I've cut aluminum in those (with backing), but these heatsinks have a lot of fins, I'm not sure how well that would work.
Do you think a plastic/aluminum blade in a chop saw would work to cut these?
I assume a bandsaw would be best, but I don't have one of those. Table saw and a chop saw I do have, and I've cut aluminum in those (with backing), but these heatsinks have a lot of fins, I'm not sure how well that would work.
I would think that if you had the right blade and clamped it down tightly, you could get a good cut with the chopway (it is the same as a sliding miter saw, right?)
More pictures of PedroPO's amp in this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=7278
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Brian
More pictures of PedroPO's amp in this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=7278
--
Brian
Thanks
Correct, it's a woodworking saw, although it doesn't slide. It's a 12" compound miter saw.
I've seen problems with thin pieces (1/8") of Al (L piece) going through the table saw; sometimes the piece of Al 'flexes' and then it tends to 'shoot'. I started clamping a piece of wood on the top of the Al L, in addition to the wood fence behind it.
Kickback is not fun
but that should be less of an issue with the Compound Miter saw.
Correct, it's a woodworking saw, although it doesn't slide. It's a 12" compound miter saw.
I've seen problems with thin pieces (1/8") of Al (L piece) going through the table saw; sometimes the piece of Al 'flexes' and then it tends to 'shoot'. I started clamping a piece of wood on the top of the Al L, in addition to the wood fence behind it.
Kickback is not fun
but that should be less of an issue with the Compound Miter saw.- Status
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