My differential input 49830 - 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 26th March 2008, 06:41 PM   #1
diyAudio Member
Join Date: May 2006
Default My differential input 49830

I basically copied their schematic but added a differential input. I decided to do four pairs for possible sub amp use but would start with one pair and add them if power requirements warrant.

Alothough I have the IR FET's there I am considering the Toshiba's mentioned in the 4702 app note.

One thought I had was to drop back to two FET pairs and parallel two boards for the sub. I would just swap the differential pair of one to basically do a bridged design. That's what the BPA-300 design essectially does with seemingly excellent results.

Any suggestions for improvement?
Attached Files
File Type: pdf schematic prints.pdf (24.2 KB, 326 views)
  Reply With Quote
Old 26th March 2008, 08:44 PM   #2
diyAudio Member
Join Date: Apr 2005
Location: In the Wild, Wild West
Some of the final values will depend on the PCB layout. The compensation capacitor and gate resistors, for example. Be prepared to adjust them for full stability. The bias may also need to adjust depending on where you want to bias your design. Be sure the drain supply bypassing is close to the FET as possible.

  Reply With Quote
Old 26th March 2008, 09:06 PM   #3
diyAudio Member
Join Date: May 2006
Thanks! I was counting on doing some tweaking. My guess is that going from one FET pair to two or more may also require tweaking.
  Reply With Quote
Old 27th March 2008, 12:07 AM   #4
diyAudio Member
Join Date: Aug 2007
Zobel network/filter at the output.
  Reply With Quote
Old 28th March 2008, 05:20 AM   #5
diyAudio Member
Join Date: May 2006
Thanks, I forgot to add that.

If that's the worst of it I'll have to pat myself on the back!
  Reply With Quote
Old 6th May 2012, 11:44 AM   #6
diyAudio Member
Join Date: May 2011
Very good circuit!!!
  Reply With Quote
Old 6th May 2012, 11:38 PM   #7
djk is offline djk
diyAudio Member
djk's Avatar
Join Date: Feb 2001
Location: USA
The source resistors aren't big enough to do any real good.

I would consider using an FET for the bias thermal compensation device, it will have a better tempco than a BJT for this circuit. C14 needs to be much bigger than 10pF, I would prefer 10F.
Candidates for the Darwin Award should not read this author.
  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
JLH with a differential input stage mohan72 Solid State 46 10th September 2008 07:59 PM
Adding a third input to a differential input stage? maudio Solid State 15 11th October 2006 02:16 AM
Differential input stage Dynsdale Tubes / Valves 8 3rd September 2005 07:29 PM
differential input stage xuesong Solid State 3 27th December 2004 02:08 PM

New To Site? Need Help?

All times are GMT. The time now is 11:23 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