Using many smaller heatsinks instead of two larger ones

rtarbell · 7th September 2008, 05:47 AM

For large solid state amplifiers, has anyone used individual heatsinks for their output transistors instead of one or two large plate heatsinks that all of the devices are mounted to?

I am having good luck finding cheap ~60mm X 60mm heatsinks on eBay that are intended for microprocessor CPU cooling ---> If I have 10 output devices in my amplifier (TO-3P plastic package), can I buy 10 of these heatsinks and mount all of my TO-3P output transistors to their own individual heatsink? Is there any problem that the transistors will not be "sharing" their heat with their neighbors?

After doing the math, some of these heatsinks sell for $3 each --> 10 X $3 = $30, which is cheaper than the cost of the larger heatsinks that can hold 5 devices a piece, from what I have found.

Geek · 7th September 2008, 06:04 AM

This is exactly what I'm doing for a Pass Labs project.... using many honkin' fanned CPU heatsinks I found surplus for really cheap.

I'm now working on the manifold and silencer for the fans

Cheers!

Spiny · 7th September 2008, 10:05 AM

CPU heatsinks are designed for forced air cooling, the fins are thin and spaced to near together for convection cooling.
They are cheap and I use them for many things (PSU's, chipamps etc ) a fan is neaded for any real heat dissapation though, can be noisy

Minion · 7th September 2008, 05:33 PM

Well I think it depends on the AMP...Many Discrete amps have a Transistor that has to be attached to the same heatsink at the output transistors for thermal sencing.....

Cheers

zlast · 7th September 2008, 05:52 PM

There are some significant advantages to having a single large heatsink verses multiple small ones. Check out www.apexjr.com.
He has some large heatsinks at good prices.

wg_ski · 12th September 2008, 01:00 PM

You really do need one big heatsink. However, you can make one out of a bunch of smaller identical ones by gluing them together with epoxy. Coat the ends and use a bar clamp until it fully cures.

If you end up using a separate one for the + and - banks, you'll need separate thermal compensation for each unless the air flow is dead even between them.

7th September 2008, 05:47 AM	#1
rtarbell diyAudio Member Join Date: Sep 2005	Using many smaller heatsinks instead of two larger ones For large solid state amplifiers, has anyone used individual heatsinks for their output transistors instead of one or two large plate heatsinks that all of the devices are mounted to? I am having good luck finding cheap ~60mm X 60mm heatsinks on eBay that are intended for microprocessor CPU cooling ---> If I have 10 output devices in my amplifier (TO-3P plastic package), can I buy 10 of these heatsinks and mount all of my TO-3P output transistors to their own individual heatsink? Is there any problem that the transistors will not be "sharing" their heat with their neighbors? After doing the math, some of these heatsinks sell for $3 each --> 10 X $3 = $30, which is cheaper than the cost of the larger heatsinks that can hold 5 devices a piece, from what I have found.

7th September 2008, 05:52 PM	#5
zlast diyAudio Member Join Date: Sep 2004 Location: none	Heatsink There are some significant advantages to having a single large heatsink verses multiple small ones. Check out www.apexjr.com. He has some large heatsinks at good prices. __________________ none

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7th September 2008, 06:04 AM	#2
Geek diyAudio Member Join Date: Sep 2004	This is exactly what I'm doing for a Pass Labs project.... using many honkin' fanned CPU heatsinks I found surplus for really cheap. I'm now working on the manifold and silencer for the fans Cheers!

7th September 2008, 10:05 AM	#3
Spiny diyAudio Member Join Date: Feb 2008	CPU heatsinks are designed for forced air cooling, the fins are thin and spaced to near together for convection cooling. They are cheap and I use them for many things (PSU's, chipamps etc ) a fan is neaded for any real heat dissapation though, can be noisy

7th September 2008, 05:33 PM	#4
Minion diyAudio Member Join Date: May 2006	Well I think it depends on the AMP...Many Discrete amps have a Transistor that has to be attached to the same heatsink at the output transistors for thermal sencing..... Cheers

12th September 2008, 01:00 PM	#6
wg_ski diyAudio Member Join Date: Oct 2007	You really do need one big heatsink. However, you can make one out of a bunch of smaller identical ones by gluing them together with epoxy. Coat the ends and use a bar clamp until it fully cures. If you end up using a separate one for the + and - banks, you'll need separate thermal compensation for each unless the air flow is dead even between them.

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