Super Leach diode problem - 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 3rd August 2002, 09:22 PM   #1
diyAudio Member
 
supernet's Avatar
 
Join Date: Dec 2001
Location: Europe
Question Super Leach diode problem

I am buliding a stereo Super Leach amp this time and I do not understand where to put 4 diodes on heat sink. My amplifier has two heat sinks per one side. I put 4 PNP transistors at one and 4 NPN at the second, but where to put 4 diodes?

Thanks for help!!

Supernet
  Reply With Quote
Old 3rd August 2002, 11:04 PM   #2
diyAudio Member
 
Join Date: May 2002
Location: Cincinnati, OH now Columbus,OH USA
Send a message via AIM to BeanZ
Drill holes and put the diodes in the holes through the heatsink in between two middle transistors on the heatsink. I could be the heatsink with either the NPN or PNP. They should run at approximately the same temperature and will keep the amplifier thermally stable. Good luck

BeanZ
__________________
BeanZ
  Reply With Quote
Old 4th August 2002, 02:32 PM   #3
diyAudio Member
 
supernet's Avatar
 
Join Date: Dec 2001
Location: Europe
So, it doesn´t matter on which heatsink you put them?

Supernet
  Reply With Quote
Old 4th August 2002, 05:14 PM   #4
diyAudio Member
 
Join Date: Jun 2001
Location: Flanders, Belgium
Another suggestion, I've used BYV29 diodes (see pic) for the bias circuit, they are easier to mount on the heatsinks (use also isolation!! and cooling paste).

I would use one heatsink per channel (so 2 NPN's, 2 PNP's and 2 diodes on one heatsink).

best regards,

HB.
Attached Images
File Type: jpg byv29.jpg (3.7 KB, 462 views)
  Reply With Quote
Old 5th August 2002, 02:10 AM   #5
diyAudio Member
 
Join Date: May 2002
Location: Cincinnati, OH now Columbus,OH USA
Send a message via AIM to BeanZ
hugobross mentioned it but it can not be stressed enough. Make sure that you test the continuity between the tab on the TO-220 package to the heatsink. There should be no continuity! Catastrophic failure is emminent if there becomes continuity. I recommend the SIL-PADS by Berquist. They are good performers and you always know that there is not continuity.

BeanZ
__________________
BeanZ
  Reply With Quote
Old 5th August 2002, 07:35 AM   #6
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Here is an another idea: You can use almost any PN-junction (diode) to create the -mV/degree thing. You can use isolated transistors. Connect the base to the collector, then you have a diode if you use base(collector) and emitter. You can also use (collector - base) and (emitter - base). These two types of diodes have different properties but in your application I think it's of no (or minor) importance.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy. Still time for signing up.
  Reply With Quote
Old 5th August 2002, 02:22 PM   #7
diyAudio Member
 
supernet's Avatar
 
Join Date: Dec 2001
Location: Europe
Thanks for advice!

Supernet
  Reply With Quote
Old 12th August 2002, 01:53 AM   #8
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
The Motorola (ON Semiconductor) MJF122/127 are a fully isolated TO220 type transistor that can be used as a pair of diodes (they are a Darlington type).
  Reply With Quote
Old 12th August 2002, 03:06 AM   #9
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
I would keep the original diode scheme and put them on one of the heatsinks and see how it works. If you have problems (such as one heatsink being hotter then the other), then put 2 PNP and 2 NPN on each heatsink instead. I talked to Dr. Leach about this a few months ago, when I was considering seperate heatsinks for my superamp, and I think he suggested 2 and 2 with the diodes on one, but I can't remember exactly, since i found a heatsink with 8 - to-3 holes to use instead.

Good luck,

--
Brian
  Reply With Quote
Old 12th August 2002, 06:31 AM   #10
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
Actually, the 122/127 is not a good idea. There is a low value resistor around one BE junction. I wish the STV4H bias diodes were still available. NTE still has the three junction ones, but no four junction ones.
  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
High Current Leach/leach super amp bowdown Solid State 41 2nd March 2011 02:15 PM
Leach Super Amp HELP ... Ahmad_tbp Solid State 22 28th December 2009 05:44 AM
1N4747 diode in leach amp Wagener Solid State 1 3rd May 2004 09:52 AM
I need some help with super Leach amp! supernet Solid State 5 22nd April 2002 09:27 PM
Leach amp vs super Leach amp supernet Solid State 0 21st February 2002 10:16 PM


New To Site? Need Help?

All times are GMT. The time now is 11:40 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