Composite ICs - 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
Thread Tools Search this Thread
Old 16th December 2005, 04:24 PM   #1
00940 is offline 00940  Belgium
diyAudio Member
Join Date: Sep 2003
Location: Paris
Default Composite ICs

I was browsing through Jung's book (opamp applications) and I saw the schematic posted below (chapter 6, p202). It is claimed that such arrangement would : lower noise, boost open loop gain and isolate thermally the input section.

Has anyone built something like that ? Would it be interesting or not ? The idea would be to use an OPA549 or something like that.
Attached Images
File Type: gif composite.gif (9.8 KB, 394 views)
  Reply With Quote
Old 16th December 2005, 05:30 PM   #2
lineup is offline lineup  Sweden
diyAudio Member
lineup's Avatar
Join Date: Dec 2005
Location: the north
I have seen such circuit used in Phono RIAA circuit
mainly to get get very low noise, I suppose.

Will add one more stage to inside OP-amp stages.
And of course will be very high open loop gain.
This might not be always a good thing.
  Reply With Quote
Old 17th December 2005, 04:01 PM   #3
diyAudio Member
Join Date: Nov 2003
Location: Tempe, AZ
A more technical and detailed explanation of the ides behind compound opamps is (again by Walt) found at

The idea is very popular with the headphone-amp-building folks who publish on

While I haven't tried it with a chip power amp, the line drivers in my system use the AD815 inside the feedabck loop of an opamp, and I can attest to better sound than either alone.

- bkb
  Reply With Quote
Old 18th December 2005, 06:52 AM   #4
Electrons are yellow and more is better!
diyAudio Member
peranders's Avatar
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
00940, such design is a bit historical because nowadays there is not much sense to do this because the opamps are much better now but it works alright.

If you compare Walt's suggestion with AD797 I think the latter is better and definitely smaller/cheaper.
/Per-Anders (my first name) or P-A as my friends call me
Group buy Pavel Dudeks excellent LM4780 based amp Sign up here
  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
DIY composite platter marekst Analogue Source 23 8th October 2010 07:19 PM
Composite Plinth Capt Zach Analogue Source 5 24th July 2006 09:40 PM
composite to XLR Skoda_101 Analog Line Level 2 15th March 2006 09:50 AM
Composite opamps biovizier Solid State 1 12th April 2005 01:52 AM

New To Site? Need Help?

All times are GMT. The time now is 12:45 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright ©1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2