Matching Jfets - 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 20th January 2010, 02:36 AM   #1
diyAudio Member
Sunsun22's Avatar
Join Date: Jul 2004
Location: Hong Kong
Default Matching Jfets

I am matching Jfets (J74/K170) with a curve tracer.

When matching same channel Jfets for preamp, should I choose closest Idss or closest gradiant pairs?

What about matching N-P channel Jfets?

  Reply With Quote
Old 20th January 2010, 07:14 AM   #2
h_a is offline h_a  Europe
diyAudio Member
h_a's Avatar
Join Date: Sep 2006
Location: Graz, Austria
I could imagine that in a differential pair closest gradient could be better, but without checking it with a distortion analyzer we will never know.

Don't expect too much from matching, the very most people are happy with IDSS-sorted jfets.

N to P matching is usefull to lower offset, but with respect to distortion cancellation I never had the time to test it, but I'm still thinking of it.

Have fun, Hannes
  Reply With Quote
Old 20th January 2010, 01:58 PM   #3
diyAudio Member
Sunsun22's Avatar
Join Date: Jul 2004
Location: Hong Kong
Thank you, that's what I think too. Matching uses up a lot of time but the result is still ????
  Reply With Quote
Old 20th January 2010, 02:08 PM   #4
AndrewT is offline AndrewT  Scotland
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
closest gradient over the SAME current range.
That requires the gradient to be measured at fixed matching currents.
How do you do that at a fixed and repeatable Tj?

The above condition virtually demands selecting the same Idss to yield the same gradient at a lesser operating current.
regards Andrew T.
Sent from my desktop computer using a keyboard
  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
Matching Jfets NickC Solid State 13 23rd December 2013 11:18 PM
SiC JFETS revintage Pass Labs 15 27th August 2009 02:43 PM
jfets for preamp kzeprf22 Solid State 14 21st November 2008 02:35 PM
Matched JFETs suzyj Solid State 8 22nd August 2007 02:10 AM

New To Site? Need Help?

All times are GMT. The time now is 08:33 PM.

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