637 Amplifiers - 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 25th June 2012, 02:17 PM   #1
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao
Default 637 - Class AB Amplifier

OPAM 637 is very popular with the OPA structure is simple.
I'm inspired by it and the amplifier circuit diagram has the same structure to create this amplifier 637.

This is the inner structure of OPAM
Attached Images
File Type: jpg Opam-627-.jpg (67.0 KB, 1934 views)
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html

Last edited by quanghao; 5th July 2012 at 11:09 PM. Reason: 637 - Amplifier
  Reply With Quote
Old 25th June 2012, 02:21 PM   #2
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao
and , please see it
Attached Images
File Type: jpg opam-627-2.jpg (116.1 KB, 1856 views)
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
  Reply With Quote
Old 25th June 2012, 02:49 PM   #3
Bonsai is offline Bonsai  Taiwan
diyAudio Member
 
Bonsai's Avatar
 
Join Date: Jul 2003
Location: Taipei, Taiwan
You have removed the LTP current mirror. Although I expec this design will work without it, loop gain will be lower and current balance in the LTP will not be optimum. Both of these will lead to higher distortion.
__________________
bonsai
Amplifier Design and Construction for MUSIC! http://hifisonix.com/
  Reply With Quote
Old 26th June 2012, 04:52 AM   #4
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao
Quote:
Originally Posted by Bonsai View Post
You have removed the LTP current mirror. Although I expec this design will work without it, loop gain will be lower and current balance in the LTP will not be optimum. Both of these will lead to higher distortion.
please see this mode OPA 637
Attached Images
File Type: jpg 637-3.jpg (86.0 KB, 1698 views)
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
  Reply With Quote
Old 26th June 2012, 04:57 AM   #5
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao
and one opam 637
Attached Images
File Type: jpg Opam-627-mode.jpg (135.2 KB, 1624 views)
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
  Reply With Quote
Old 26th June 2012, 07:55 AM   #6
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao
and the end my amli finis ,
Attached Images
File Type: jpg 637-amli.jpg (120.4 KB, 1486 views)
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html

Last edited by quanghao; 26th June 2012 at 08:03 AM.
  Reply With Quote
Old 26th June 2012, 08:08 AM   #7
forr is offline forr  France
diyAudio Member
 
forr's Avatar
 
Join Date: Dec 2004
Location: Next door
The voltage reference of the common base transistors in the cascode input stage is ground and not as in the 637.
  Reply With Quote
Old 26th June 2012, 08:15 AM   #8
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao
the constant current circuit diagram for the j-fet input, very little noise and running smoothly!
Attached Images
File Type: jpg New-CCS.jpg (97.3 KB, 574 views)
File Type: jpg Circuit-new-CCS-.jpg (94.8 KB, 407 views)
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
  Reply With Quote
Old 26th June 2012, 08:18 AM   #9
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao
Quote:
Originally Posted by forr View Post
The voltage reference of the common base transistors in the cascode input stage is ground and not as in the 637.
I changed them and test simulation software running on Mutisim.

a fun change, but pretty good results!
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
  Reply With Quote
Old 26th June 2012, 09:07 AM   #10
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
Quote:
Originally Posted by quanghao View Post
the constant current circuit diagram for the j-fet input, very little noise and running smoothly!
It is usually not much different in noise that can be seen in simulation of different CCS topologies. Worse, lower noise doesn't always mean better sounding. I'm still not sure if I want to go the trouble building such a complex current source. What is your experience. Is it a big improvement soundwise? I mean, are you just relying on simulation numbers?

ADD: Note that the amp would probably be using regulated front end supply

Last edited by Jay; 26th June 2012 at 09:12 AM.
  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
Jackson 637 Tube tester Info needed Zero Cool Tubes / Valves 0 19th September 2008 10:46 PM
Opa627/637 for sale Audio.Spec1 Swap Meet 1 4th August 2007 11:29 AM
Fs: Bb Opa627,637 vadimgal Swap Meet 6 14th January 2007 03:27 AM
Fs: Opa627/637, Ad1862 vadimgal Swap Meet 0 9th July 2006 02:16 PM


New To Site? Need Help?

All times are GMT. The time now is 02:29 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