Thermal management - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 14th May 2008, 03:19 PM   #1
diyAudio Member
 
Join Date: Mar 2008
Send a message via AIM to Linear Purpose Send a message via MSN to Linear Purpose Send a message via Yahoo to Linear Purpose
Default Thermal management

In solid sate amplifier thermal management is a critical point for performance an reliability.

Nevertheless it is often an under estimated part of the design.

For example there is still people using MICA insulators (which are completely obsolete) between transitors and dissipator ...

There is certainly lots of ideas to share on that subject !
  Reply With Quote
Old 14th May 2008, 05:53 PM   #2
CBS240 is offline CBS240  United States
diyAudio Member
 
CBS240's Avatar
 
Join Date: Aug 2005
Location: K-town
Quote:
...For example there is still people using MICA insulators (which are completely obsolete) between transitors and dissipator ...
Mica is obsolete My mica insulators work quite well if you mount them properly. There may be material out there that works a little better but when you factor in the price...
You just have to deal with the heatsink grease.
__________________
All the trouble I've ever been in started out as fun......
  Reply With Quote
Old 14th May 2008, 06:13 PM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Mica insulators conduct heat better than many of the new insulators that are marketed.

The main purpose and reason for these "dry" insulators is to save assembly time.
__________________
regards Andrew T.
  Reply With Quote
Old 14th May 2008, 06:13 PM   #4
diyAudio Member
 
Join Date: Sep 2004
Location: mendoza
Quote:
Originally posted by CBS240

"It is not a disgrace to fail. Failing is one of the greatest arts in the world."
I usually fail with complete succes...
  Reply With Quote
Old 14th May 2008, 06:29 PM   #5
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
By far the best way is to mount the transistors directly to the heatsink, but that creates other headaches. You either have to run the sinks electrically hot or limit yourself to a grounded collector topology.
  Reply With Quote
Old 14th May 2008, 06:36 PM   #6
Dr_EM is offline Dr_EM  United Kingdom
diyAudio Member
 
Dr_EM's Avatar
 
Join Date: Oct 2006
Location: Swindon
The mechanical mount is important too. Using Hex head bolts will help and ideally a clamp can be used (again tightened with hex type bolts). For insulators I tend to use Sil-Pads, seem to work pretty well (had a heatsink untouchably hot in one test setup but the chips never cut out or had problems).
  Reply With Quote
Old 14th May 2008, 11:19 PM   #7
diyAudio Member
 
Join Date: Nov 2004
Location: Florida
I use wide clear tape on my heatsinks, so far success and no issues.

I stick the tape on the heatsink, making sure of no air pockets, and grease the transistors, and stick them to the tape, and clamp them down. The thermal performance is good.

I'm not worried about melting the tape, because if I run it that hot, which I doubt, then I have more problems to worry about than the tape anyway.
  Reply With Quote
Old 14th May 2008, 11:28 PM   #8
Account disabled at member's request
 
MJL21193's Avatar
 
Join Date: Mar 2007
My first time I was impatient to try my creation and I used thermal grease and paper. Ordinary white printer paper cut to size. Amp had 56V rails, and it worked fine.

I later changed to mica to be on the safe side.
  Reply With Quote
Old 15th May 2008, 12:04 AM   #9
diyAudio Member
 
Join Date: Dec 2006
Location: Overtaxed Long Island, NY
Default Re: Thermal management

For example there is still people using MICA insulators (which are completely obsolete) between transistors and dissipator ...

Obsolete??? I would not use anything else. As others have stated and I verified for myself the other types have worse thermal performance than mica and good thermal grease.
  Reply With Quote
Old 15th May 2008, 12:24 AM   #10
diyAudio Member
 
Join Date: Nov 2004
Location: Florida
Quote:
Originally posted by MJL21193
My first time I was impatient to try my creation and I used thermal grease and paper. Ordinary white printer paper cut to size. Amp had 56V rails, and it worked fine.

I later changed to mica to be on the safe side.
Wow, you used paper???

At least you greased it though. That thermal grease is great stuff.

I saw a car amp one time someone tried to fix, and they put pieces of fairly thick paperboard behind the transistors with no grease

Here's a heatsink I just done with clear tape. You can hardly see the tape with the naked eye
Attached Images
File Type: jpg subampsink.jpg (31.2 KB, 130 views)
  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
Biasing/thermal compensation of Thermal Trak transistors Bob Cordell Solid State 161 8th March 2014 08:42 AM
Thermal management: it this not really of concern? LowRedMoon Tubes / Valves 18 16th November 2006 01:11 AM
Thermal Management of Subwoofer Drivers Oborous Subwoofers 4 2nd November 2006 10:52 PM


New To Site? Need Help?

All times are GMT. The time now is 03:43 AM.


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