jfet preamp - does a jfet exist that'll work at just 5V supply? - Page 6 - 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 1st May 2012, 12:02 PM   #51
juma is offline juma  Germany
diyAudio Member
juma's Avatar
Join Date: Nov 2005
Location: Berlin
Post #40 doesn't mention a buffer. It shows a circuit that is common-source voltage amplifier (Q1) loaded by CCS (Q2) and wrapped in triode/Schade feedback network (R6/R7) that sets the gain at 3V/V.

Post #41 says that, if need arises, buffer can be added to an existing common-source gain stage and the circuit shows how it's done - Q3 and Q4 are introduced.
Now we come to the obvious mistake in the drawing: there is one wire too much on it, the one that connects lower ends of R4 and R9.
Q3 is a source-follower loaded with CCS (Q4) and together they form a buffer stage.
Both stages (Q1/Q2 common-source gain stage and Q3/Q4 buffer stage) are wrapped in R6/R7 feedback network that sets the gain at 3V/V.

Here is a drawing without a superfluous wire:
Attached Images
File Type: gif corr.gif (4.7 KB, 61 views)
  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
Complementary JFET-JFET cascode input, BJT VAS-Drivers, Lateral Output Neutrality Solid State 61 2nd October 2015 06:35 AM
JFET preamp? asc Chip Amps 6 10th May 2013 08:21 AM
FS: PreAmp with Complimentary JFET Diff input & JFET ouput USAcircuits Vendor's Bazaar 12 21st June 2011 11:02 AM
Can I replace BF245C JFET with J201 JFET? bigmike216 Parts 2 7th December 2005 06:50 AM
BJT cascoded with a Jfet: how can I make it work? Bricolo Parts 16 7th November 2004 06:29 PM

New To Site? Need Help?

All times are GMT. The time now is 07:50 AM.

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