Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Linearizing diodes in amp circuits.
Linearizing diodes in amp circuits.
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 19th August 2006, 04:23 PM   #1
Acoustic Absorb is offline Acoustic Absorb  Ireland
diyAudio Member
 
Join Date: Mar 2006
Location: Ireland
Default Linearizing diodes in amp circuits.

Greetings.
Are linearizing diodes ever used to linearize the transfer characteristic of transistors in audio amps? I haven't seen any examples in the schematics. Google indicates that the technique is used in RF amps and diode lasers, but no examples in audio amps that I can find. Is there any role for them? what are the difficulties in using the technique? Are there any casualties among you from attempts to make it work? I look forward to your views with interest.
  Reply With Quote
Old 19th August 2006, 05:29 PM   #2
lumanauw is offline lumanauw  Indonesia
diyAudio Moderator Emeritus
 
lumanauw's Avatar
 
Join Date: Oct 2002
Location: Bandung
Send a message via Yahoo to lumanauw
Quote:
Are linearizing diodes ever used to linearize the transfer characteristic of transistors in audio amps
Where to put diode in the transistor? You got example drawing?
  Reply With Quote
Old 19th August 2006, 05:59 PM   #3
davidallancole is offline davidallancole  Canada
diyAudio Member
 
Join Date: Nov 2005
Take a look at this:

http://ca.search.yahoo.com/search?p=...-web-t912&b=11

Go to number 12.
  Reply With Quote
Old 19th August 2006, 06:45 PM   #4
lumanauw is offline lumanauw  Indonesia
diyAudio Moderator Emeritus
 
lumanauw's Avatar
 
Join Date: Oct 2002
Location: Bandung
Send a message via Yahoo to lumanauw
It is LM13600

Is the linearizing diode is D2 and D3? What are they doing there? What's the mechanism to obtain the "linearizing"? Won't the DC offset annoyed?
Attached Images
File Type: jpg lm13600.jpg (21.2 KB, 393 views)
  Reply With Quote
Old 19th August 2006, 07:21 PM   #5
Acoustic Absorb is offline Acoustic Absorb  Ireland
diyAudio Member
 
Join Date: Mar 2006
Location: Ireland
>Where to put diode in the transistor? You got example drawing?

I haven't sketched any examples yet. I will study the examples referenced in the reply from member lumanauw before spending time on it. I am putting off working on this idea in case there are some compelling reasons to avoid it.
  Reply With Quote
Old 19th August 2006, 07:32 PM   #6
Acoustic Absorb is offline Acoustic Absorb  Ireland
diyAudio Member
 
Join Date: Mar 2006
Location: Ireland
>Take a look at this:
>http://ca.search.yahoo.com/search?p...b-web-t912&b=11
>Go to number 12.

There is plenty of material to study there. I am still curious why there are no examples of discrete amps using linearizing diodes.

I expect it is easier use them in ICs due to better matching of diode and transistor properties when they are on the same die.
  Reply With Quote
Old 19th August 2006, 07:37 PM   #7
Acoustic Absorb is offline Acoustic Absorb  Ireland
diyAudio Member
 
Join Date: Mar 2006
Location: Ireland
>Where to put diode in the transistor? You got example drawing?

I expect I would use them to linearize the input transistors which give voltage gain. Small signal transistors; FETs and tubes all seem to have a non linear transfer characteristic and so there might be a role for linearizing diodes. This would be an alternative to high open loop gain with feedback to achieve linearity.
  Reply With Quote
Old 19th August 2006, 07:53 PM   #8
darkfenriz is offline darkfenriz  Poland
diyAudio Member
 
darkfenriz's Avatar
 
Join Date: Jun 2004
Location: Warsaw
You can "linearize" current driven common emitter stage to current mirror. You will get lower gain, but better linearity. Good basic example?
Attached Images
File Type: jpg bez tytułu.jpg (21.7 KB, 351 views)
  Reply With Quote
Old 19th August 2006, 11:51 PM   #9
john curl is offline john curl  United States
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
Very hard to do right, except by experts.
__________________
"Condemnation without Examination is Prejudice"
  Reply With Quote
Old 20th August 2006, 12:00 AM   #10
latala is offline latala  United Kingdom
diyAudio Member
 
Join Date: Feb 2006
Location: staffordshire
Linearizing diodes in amp circuits.
The first think that comes to my mind is the baxendall diode as used inthe Linsey Hood 75 watt design ! This is used to match the transfer characteristics between the quasi-complimentary output stage transistors !
A similar technique is also used in the old Phase linear 400/700 power amps
Regards Trev
  Reply With Quote

Reply


Linearizing diodes in amp circuits.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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Idea for linearizing a cascoded VAS ionomolo Solid State 9 27th June 2008 09:44 PM
Connecting Virtual Ground Circuits with True Ground circuits?? Minion Solid State 1 12th February 2007 02:28 AM
protection diodes in LM317 circuits jarthel Parts 2 14th September 2006 11:28 PM
Research on tubes and circuits simple circuits Cazcotty Tubes / Valves 6 16th June 2006 01:50 PM
85 powersupply circuits 58 charge circuits gev Power Supplies 0 31st July 2005 12:27 PM


New To Site? Need Help?

All times are GMT. The time now is 08:09 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki