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Canadian Heat Sink Group Buy

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H

hieroglyphics

Member
Joined 2003
sounddomain.com/id/hieroglyphics
You don't understand how badly I want in on this group buy. :bawling: But alas, I'm a poor student who can only afford king cans on the weekend and cigarettes from the states. But I've had a longing to smoke some IRFP044's for some time now.
My focus is to build a couple of versatile Aleph X monoblocks so here's what I came up with:
22VDC, 7A, 12 (maybe 16) fets. This'll give me 100 watts into 4 and 8 ohms with a peak of about 130watts at 6 ohms. I taylored these values around 2 12" sections of this heatsink:

http://www.thermaflo.com/bin/exdata...1=Change+Length

With the Rth as it is with natural convection, I fear the 40C rise may be too hot so I was thinking of putting the sinks inside the chassis and mounting fans underneath to force air through the fins and out through some vents in the top. I've seen it done before and it seems like a cool idea.

I've heard good things about the quality of the R-theta sinks. That extrusion you posted looks quite nice. The Rth given is for a 3" section, so for a 12" section would that be like paralleling 4 of them (ie. equivalent Rth = 0.05)?

What kind of time frame were you hoping for with this group buy? I'm looking to get 4 sinks of this size as soon as I'm finished exams (when I get a job). But I'd love the group buy discount.
 
Coulomb

Coulomb

Member
Joined 2002
diyaudio.com/wiki/index.php?page=Active+Group+Buys
The extrusion is a continuous form, so the 12" length is one piece, not 3 or 4 sections cobbled together. The R-theta profile is quite similar to the E3096 from Termaflo, but not quite as beefy. the 65535 from Aavid Thermalloy os a pretty close comparison to the R-theta unit. You can use the extrusion calculator on the Aavid site to give you the C/W for the length you require. I find that Aavid underates thier extrusions when compared to thier competitors, not sure why. I have not started a Wiki yet as I am still in the fact finding stage and I am trying to get our US counterparts to join the group buy.

Regards

Anthony
 
H

hieroglyphics

Member
Joined 2003
sounddomain.com/id/hieroglyphics
Sorry, I shoulda been more clear. I know they don't come in 3" sections, I was purely talking about solving for the final Rth which is given on that pic you posted as 0.5 per 3". So to solve for a 12" piece thats sorta like paralleling 4 Rth's which would yield an equivalent Rth = 0.125 (previous value I calculated was for forced, not natural /ooops). Is this correct? Or is there some other method of calculating the final Rth from a given section?

This'll be my first project so all I've got to go by is what I've read from this forum. I'm not too concerned about aesthetics cuz I'm gonna put em inside the chassis anyway.
As for which heatsink to go with, I'm not quite sure yet, but I'm easy. Whatever the popular choice is, is fine. Long as it doesn't break the bank :smash:
 
J

Jeff Reeves

Member
Joined 2004
65340 heatsink

Can I now assume that we are targeting the R-theta 65340 heatsink and not the Thermaflo E3096? My preference would be for the 65340 as shipping charges would not apply to me(I live in Ajax). They are already cut and anodized,and an exact price can be calculated. Myself, I'm in for 8 pieces:cool:
 
Coulomb

Coulomb

Member
Joined 2002
diyaudio.com/wiki/index.php?page=Active+Group+Buys
Well I got a quote on shipping from Thermaflo in the US to my door in Toronto and it is very costly.

Weight per 8' length is 80lbs. Total weight for
3 pieces would be 240lbs.

Each 48" length would be 40lbs.

USPS-Each 4' piece must be shipped individually.
$48.75ea. for Parcel post, 4-6wks.
$83.75ea. for Airmail, 4-10 days.

UPS-2 4'pcs per package
$247.10ea. for Ground, 7 days.

Those are $US Dollars folks.

So Thermaflo out, R-Theta in!

As soon as I can get someone to start a Wikki for me, I don't have a clue, I am going to try to hit the 50 watermark for the R-Theta finished product.

If you remember, I posted earlier in this thread, a finished 12" section with a four Process black Anodizing finish would cost $52.50 CAD FOB thier Mississauga location. Profile# 65340 just above.

Theresa at R-Theta has indicated the average cost of shipping anywhere in Canada is $1 per pound or $12 CAD per heatsink.

For those of you who are interested within a 2 or 3 hour drive of Mississauga, you may want to pick up your orders. I would need to pay R-Theta for the complete order in advance so I would need to collect all the funds via PayPal plus the 3% service charge they will charge me.

Once we have 50 units on the wiki (could take a while) I will post payment instructions. Anyone want to volunteer to set up a Wikki for a Canadian Heat Sink Group Buy?

Regards

Anthony
 
Peter Daniel

Peter Daniel

Member
Joined 2002
audiosector.com
Paid Member
Coulomb said:
I would need to pay R-Theta for the complete order in advance so I would need to collect all the funds via PayPal plus the 3% service charge they will charge me.

Once we have 50 units on the wiki (could take a while) I will post payment instructions. Anyone want to volunteer to set up a Wikki for a Canadian Heat Sink Group Buy?
Click to expand...

Last time, personal payments could be made directly to R-Theta by using credit cards.
 
Coulomb

Coulomb

Member
Joined 2002
diyaudio.com/wiki/index.php?page=Active+Group+Buys
Peter Daniel said:
I used my credit card, not hers;)

This was all before GC madness. I already sold 2/3rds of those heatsinks at USD$50/pc. I actually made some money on that (considering 15% local taxes and low US$, it wasn't much) and made some members happy as well.
Click to expand...

Hey Peter can you setup a wikki for me so I can gauge the committment level of all interested parties?

Thanks

Anthony
 
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