Twisted X Overture - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated 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 14th June 2006, 04:19 PM   #1
diyAudio Member
 
Russ White's Avatar
 
Join Date: Jan 2005
Location: Nashville, TN, USA
Send a message via Yahoo to Russ White
Default Twisted X Overture

Hello,

I am not sure how many of you have followed my new chip amp design which is based on ideas proposed in this thread.

http://www.diyaudio.com/forums/attac...amp=1087758354

The idea is a bridged power amp that takes advantage of the "Super Symmetry" effects of the THS4131 and itself is also Symmetric.

So while maturing of the idea is largely to be credited to Nelson Pass and to Terry Aben and others (I don't have time to list them all) who worked very hard to get a discrete circuit going that modeled Nelson's copyrighted schematic, my design is substantially different, in that the only patented IP is wrapped up in the THS4131 and the LM3886. That said I fully recognize the work that went into Super Symmetry and want to be sure to credit that to Nelson Pass and thank him for sharing his ideas on a chipamp which benefits from it.

I wanted a “Symmetric” design but without the big caps in the signal path which the design that Nelson had proposed included, and without the worry of having to license anything from anyone or infringe on anyones patent or IP. The only IP I used was my own and that which was licensed to TI, or that which is readily usable without restriction.

For my part, I also place no restrictions on the material I present here, I simply request that the design I provide only be used for DIY audio. What is free, should remain free. Free as in speech.

My design utilizes the THS4131(or OPA1632 which will also work) to drive the power opamps (LM3886 in this case). The THS4131 is “Super Symmetric” in operation, and that gives my design some serious benefits when it come to CMMR. It is also a very fast part, and has excellent slew rate and settling time.

My design is really nothing more then a LM3886 nested in the feedback of a fully differential opamp. The THS4131 must be compensated with two small value(200pf) to make the circuit stable since the THS4131 is operating substantially faster than the LM3886 at the gains involved.

The input is balanced, and sounds best that way (lowest noise/distortion) but it can also handle single ended input.

There is an optional zobel network on the outputs for those with difficult to drive speakers. They actually can generally be omitted.

The amplifier has 20db of gain and has been tested with 28V rails.

It should be capable of 80W or so into 8ohms and 130W or so into 4ohms.

My heartfelt thanks to Terry Aben for all his support and encouragement, and the rest of the crew on the Pass Labs forum for their guidance in this endeavor. Terry did a superb job on his design which is based on Nelson's published circuit.

It is my hope this project will bring enjoyment to others and perhaps even spawn ideas for other circuits.

Cheers!
Russ
Attached Files
File Type: pdf x-amp1.sch.pdf (69.8 KB, 1713 views)
__________________
Less pulp more juice Twisted Pear Audio.
  Reply With Quote
Old 14th June 2006, 05:00 PM   #2
diyAudio Member
 
Russ White's Avatar
 
Join Date: Jan 2005
Location: Nashville, TN, USA
Send a message via Yahoo to Russ White
Default PCB PDFs

Here are PDFs for a single side PCB for this project. the PCB is by no means optimal, but it works just fine. I have had excelent results.

PCB PDFs

The copper side is not mirrored and the silk screen is mirrored for toner transfer.

Note that the THS4131 is mounted on the bottom, with pin #1 corner marked with a "1".

I have a much better optimised two sided design which I will be producing very soon.

Cheers!
Russ
__________________
Less pulp more juice Twisted Pear Audio.
  Reply With Quote
Old 14th June 2006, 07:05 PM   #3
diyAudio Member
 
vdi_nenna's Avatar
 
Join Date: Oct 2000
Location: PA, USA
Blog Entries: 1
Send a message via Yahoo to vdi_nenna
Hey, count me in. I don't want to miss this! Nice work!
  Reply With Quote
Old 14th June 2006, 08:18 PM   #4
diyAudio Member
 
Join Date: Mar 2003
Location: Windsor
My god Russ that has to be the funniest post I have ever read! It reads like a cellphone service agreement LOL!

Other than making me laugh, it looks like a really nice circut! I might give this one a try.
__________________
If you take something apart and put it back together again enough times, eventually you will have two of them.
  Reply With Quote
Old 14th June 2006, 08:32 PM   #5
diyAudio Member
 
BrianDonegan's Avatar
 
Join Date: Dec 2004
Location: TPA HQ
Quote:
It reads like a cellphone service agreement
Maybe a "whereas" and a few "heretofore"s...
__________________
Twisted Pear Audio
  Reply With Quote
Old 14th June 2006, 08:36 PM   #6
diyAudio Member
 
Russ White's Avatar
 
Join Date: Jan 2005
Location: Nashville, TN, USA
Send a message via Yahoo to Russ White
Quote:
Originally posted by Gcollier
My god Russ that has to be the funniest post I have ever read! It reads like a cellphone service agreement LOL!

Other than making me laugh, it looks like a really nice circut! I might give this one a try.
Just being extra extra careful not to step on toes. You just never know these days....
__________________
Less pulp more juice Twisted Pear Audio.
  Reply With Quote
Old 15th June 2006, 05:12 PM   #7
diyAudio Member
 
Join Date: Apr 2002
Location: Cayman Islands
Hi Russ,

Pardon my ignorance,

Is this going to be the SuSy (in development) kit on your site?

If so, any ideas as to a timeframe of it becoming available?

Thanks

Andrew
__________________
None of us are leaving this world alive. Enjoy it responsibly as you may.
  Reply With Quote
Old 15th June 2006, 05:42 PM   #8
diyAudio Member
 
BrianDonegan's Avatar
 
Join Date: Dec 2004
Location: TPA HQ
Yes. I updated the names on the web site. Thanks for the reminder!
__________________
Twisted Pear Audio
  Reply With Quote
Old 15th June 2006, 10:46 PM   #9
maxw is offline maxw  United Kingdom
diyAudio Member
 
maxw's Avatar
 
Join Date: Jun 2004
Location: London
Can't wait
  Reply With Quote
Old 22nd June 2006, 05:39 AM   #10
maxw is offline maxw  United Kingdom
diyAudio Member
 
maxw's Avatar
 
Join Date: Jun 2004
Location: London
Any progress on a double-sided PCB?
I've started making a chassis already
  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
FS: Twisted Pear TXO-2 Overture Amp Paul Ebert Swap Meet 2 12th May 2009 04:08 PM
FS: National Overture Class-D Demo Board Amp speaker Swap Meet 3 24th March 2009 03:05 PM
Overture for sale Peter Menting Swap Meet 1 21st June 2008 12:14 PM
Unprotected Overture Design Guide 1.4 scgibson81 Chip Amps 1 23rd June 2004 05:13 PM


New To Site? Need Help?

All times are GMT. The time now is 08:12 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