Heatplane instead of heatsink? - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 15th September 2005, 01:33 PM   #1
rif is offline rif  United States
diyAudio Member
 
rif's Avatar
 
Join Date: Jan 2003
Location: Southern NJ
Default Heatplane instead of heatsink?

I've been reading the PLH posts and docs, and an "opportunity" re power JFETs dissipation abilities is mentionned a few times.

Wouldn't the use of a heatplane instead of a heatsink greatly help? Of course you still need to transfer the nrg to ambient surroundings, but the heatplane would very efficiently move it away from the power JFET.

just a thought.
  Reply With Quote
Old 15th September 2005, 11:04 PM   #2
azira is offline azira  United States
diyAudio Member
 
Join Date: Dec 2003
Location: Near Seattle
Intuitively, I would say that a heat plane would not work as well as a heat sink. Note that I am not saying that a heat plane would not work at all.

A heatsink is fins attached to a slab of metal. That slab of metal is essentially your heat plane. So then you can consider a heatsink as a heat plane with fins which should always out perform a simple heat plane.

Of course there is a matter of size. At some size, a heat plane would be able to perform as well as a given heatsink. But that size is considerably larger (think relative surface area).

Perhaps what you might be thinking of is a heat spreader (such as used on many CPU coolers). Many have hunks of copper embedded in an aluminum heat sink becuase the copper is more efficient at sending that heat around while the aluminum is better at radiating it.
--
Danny
  Reply With Quote
Old 16th September 2005, 01:17 PM   #3
rif is offline rif  United States
diyAudio Member
 
rif's Avatar
 
Join Date: Jan 2003
Location: Southern NJ
Maybe I didn't use the correct term -- I'm thinking of something like a heatpipe, but in a plane instead of a pipe.

Basically a heatplane would be a hollow plane of metal. Inside the hollow is a wicking material and typically a phase change substance. The heat is transported very efficiently by the phase change substance -- instead of relying on diffusion of heat in a solid metal to carry energy, it relies on a mobile liquid/gas.

I found a link:

http://www.tsheatronics.co.jp/englis.../01_carry.html
  Reply With Quote
Old 16th September 2005, 01:37 PM   #4
Mr Evil is offline Mr Evil  United Kingdom
diyAudio Member
 
Join Date: Aug 2004
Location: Behind you
Heatpipes don't actually dissipate heat, they only move it from one place to another; you need a heatsink on one end of them anyway. They are used because it is not always possible to mount a large enough heatsink on the heat source itself. A heatpipe allows the heatsink to be located somewhere convenient, distant from the heat source.

Unless you cannot mount the transistors directly on a large enough heatsink, because of space constraints or whatever, then using a heatpipe (or 'heat plane') will not do any good.
__________________
https://mrevil.asvachin.eu/
  Reply With Quote
Old 16th September 2005, 01:43 PM   #5
rif is offline rif  United States
diyAudio Member
 
rif's Avatar
 
Join Date: Jan 2003
Location: Southern NJ
Yes, they only transport heat -- you still have to get rid of it.

But the idea is to get the heat away from the active device so that it does not overheat. You then dissipate the heat to the ambient environment where temperature rise isn't as important.

The fundamental thing to remember is the difference between heat and temperature. Move the heat away from the active device as fast as possible to keep its temperature low.

http://www.tsheatronics.co.jp/englis..._ex/index.html
  Reply With Quote
Old 16th September 2005, 02:05 PM   #6
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
i have a few dozen of these -- with a little ingenuity you could fashion this into a heatpipe -- 4 chambers and sufficient wall thickness to allow you to tap for 6-32's or 8-32's -- anyone into welding aluminum?

Click the image to open in full size.
  Reply With Quote
Old 16th September 2005, 04:53 PM   #7
Mr Evil is offline Mr Evil  United Kingdom
diyAudio Member
 
Join Date: Aug 2004
Location: Behind you
Quote:
Originally posted by rif
Yes, they only transport heat -- you still have to get rid of it.

But the idea is to get the heat away from the active device so that it does not overheat. You then dissipate the heat to the ambient environment where temperature rise isn't as important.

The fundamental thing to remember is the difference between heat and temperature. Move the heat away from the active device as fast as possible to keep its temperature low.

http://www.tsheatronics.co.jp/englis..._ex/index.html
Unfortunately it doesn't work like that. If you insert a heatpipe between the heat source and sink you are adding thermal resistance and thus the temperature of the heat source will increase. The example on the page you linked to shows using a heatpipe in place of a plain metal plate, where you will see an improvement because a heatpipe has (hopefully) a lower thermal resistance than metal, but it's still more resistance than if you attached the heatsink directly to the heat source!

You could integrate a heatpipe into a heatsink, where the heatpipe distributes heat to the fins instead of a metal baseplate. That would be a more practical application for audio amps. Indeed, some commercial heatsinks do just that.
__________________
https://mrevil.asvachin.eu/
  Reply With Quote
Old 16th September 2005, 07:18 PM   #8
rif is offline rif  United States
diyAudio Member
 
rif's Avatar
 
Join Date: Jan 2003
Location: Southern NJ
Quote:
Originally posted by Mr Evil

You could integrate a heatpipe into a heatsink, where the heatpipe distributes heat to the fins instead of a metal baseplate. That would be a more practical application for audio amps. Indeed, some commercial heatsinks do just that.

That is what I meant to communicate -- guess it didn't come across that way. I always intended a traditional heatsink at the other end -- and by moving it away from the heat source, it frees up some design constraints.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Heatsink... Lewis Moon Chip Amps 8 26th November 2008 07:22 PM
One heatsink for each mos ? pa Pass Labs 3 1st April 2002 10:29 PM


New To Site? Need Help?

All times are GMT. The time now is 10:41 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2