Class A heatsink question - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 17th January 2012, 08:31 PM   #11
djk is offline djk
diyAudio Member
djk's Avatar
Join Date: Feb 2001
Location: USA
TO-3 with grease is about 0.9°C/W in my book.

BeO2 is about 0.17°C/W.
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 17th January 2012, 09:51 PM   #12
diyAudio Member
jacco vermeulen's Avatar
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
The mica adds 0.3C/W, does not imply that Rth c-s is the same number.

(polished heatsink, polished TO-3 surface, best mica grade. mica rates from thin to thick, from best to worst origin)
It doesn't count how one deals with winning, but how to handle a loss (© DjT)
  Reply With Quote
Old 17th January 2012, 11:00 PM   #13
djk is offline djk
diyAudio Member
djk's Avatar
Join Date: Feb 2001
Location: USA
0.09°C/W, moved the decimal one place.
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 18th January 2012, 04:11 PM   #14
alibear is offline alibear  United Kingdom
diyAudio Member
alibear's Avatar
Join Date: Feb 2009
Location: Somerset
many thanks for all the assistance, much appreciated.
Andrew T, yes the 120mm fan will be fitted at the bottom of the heatsink.
Slightly off subject, using K Amps Class A Calculator I get the following results:
23V rails
3Pairs output devices
0.5 Ohm emmiter resistors
1.6Amp bias per rail
= 41W RMS and 74watts per channel heat dissapation.
Does this sound correct?
  Reply With Quote
Old 18th January 2012, 04:18 PM   #15
diyAudio Member
KatieandDad's Avatar
Join Date: Nov 2011
Location: UK
You'll be very surprised as to how little air stirring you actually need in order to improve the heatsink transfer function of the heatsinks.

In my Pass Aleph 4 I'm ditching over 400W of heat into 8 heatsinks. Using two 50mm fans running at half voltage (ie the 2 x 12V fans in series across 12V). I've reduced the heatsink temperature by nearly 10 degrees and the fan noise is almost inaudible.
  Reply With Quote


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 candidate for Class D amps CanAm Man Chip Amps 1 19th September 2011 10:36 PM
Heatsink candidate for Class A? CanAm Man Pass Labs 9 17th September 2011 06:24 PM
ab class heatsink dimensioning morpheus82 Solid State 6 21st April 2005 09:35 PM
heatsink question? xdissent Solid State 13 18th June 2004 02:44 AM
N.E.W A-60 Class A heatsink vsr123 Pass Labs 10 19th May 2004 07:45 PM

New To Site? Need Help?

All times are GMT. The time now is 11:24 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2