Jfet folded cascode with diamond buffer opamp - Page 4 - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

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 27th April 2013, 09:18 PM   #31
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
I Will test with ssm2212 tomorrow .

The input bias current Will be less than 5uA.

- Sonny
  Reply With Quote
Old 27th April 2013, 09:45 PM   #32
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
Just a shot of the difference on input and output on the squarewave signal.

Lightblue is the input.
Attached Images
File Type: png inputoutputcompare.png (18.4 KB, 138 views)
Attached Files
File Type: pdf inputoutputcompare.pdf (32.5 KB, 9 views)
  Reply With Quote
Old 27th April 2013, 10:51 PM   #33
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
I have tested the JFET opamp with NPN pair instead of jfet's.

Some of the data is:
  • Less than 2mV input offset
  • less than 4uA input offset current
  • Distortion 10 times lower at 10KHz into 220R load

The picture below is as with all the other measurement
  • 47pF compensation
  • 680mVrms out
  • 10KHz Sine
  • 0dB gain

Distortion is 0.0018% - Generator is: 0.0013%
Attached Images
File Type: jpg fft 10KHz 220R NPN pair.jpg (115.2 KB, 134 views)

Last edited by sonnya; 27th April 2013 at 11:06 PM. Reason: added measurement
  Reply With Quote
Old 28th April 2013, 09:45 AM   #34
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
still the post1 schematic?
__________________
regards Andrew T.
  Reply With Quote
Old 28th April 2013, 12:02 PM   #35
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
Quote:
Originally Posted by AndrewT View Post
still the post1 schematic?
No, it is changed a bit.

See attachment.

instead of folded cascode, i use current mirrors now. But performance is exactly the same.
Attached Images
File Type: jpg fft 10KHz 1K load 11xgain NPN pair.jpg (118.4 KB, 101 views)
File Type: jpg fft 1KHz 1K load 11xgain NPN pair.jpg (112.3 KB, 98 views)
File Type: jpg fft 1KHz No load 11xgain NPN pair.jpg (117.3 KB, 96 views)

Last edited by sonnya; 28th April 2013 at 12:32 PM.
  Reply With Quote
Old 28th April 2013, 12:34 PM   #36
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
Here is the schematic of Bipolar version of the Jfet opamp
Attached Files
File Type: pdf ssm2212rzopampv10.pdf (49.4 KB, 92 views)
  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
Folded Cascode in the Making wrenchone Solid State 11 6th March 2010 01:11 AM
All FET folded cascode driver for "JLH"-buffer with no GNFB revintage Solid State 10 29th January 2010 09:58 AM
folded-cascode FET/opamp MC phono Werner Analogue Source 33 17th January 2010 10:22 AM
folded-cascode FET/opamp MC phono Werner Analogue Source 24 12th October 2006 10:07 AM
folded cascode the_tool Chip Amps 1 27th June 2006 09:53 PM


New To Site? Need Help?

All times are GMT. The time now is 06:32 PM.


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