Advantage of a FET-BJT CCS vs BJT only - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 9th June 2009, 10:56 PM   #1
Bitrex is offline Bitrex  United States
diyAudio Member
Join Date: Jan 2009
Default Advantage of a FET-BJT CCS vs BJT only

I'm looking at a tube differential amplifier schematic, and it has a BJT biased with diodes to form a CCS, and there's a FET between the tube cathodes and the CCS. The FET's gate is connected to the transistor base and diodes, the drain going to the tube and the source connected to the BJT's collector. I guess this is called a cascode current source and I'm wondering what the advantage of putting the FET in there is vs. just connecting the tube directly to the transistor CCS? Also, if anyone can refer me or tell me the basics of how one would design such a current source I would be very appreciative!
  Reply With Quote
Old 10th June 2009, 12:21 AM   #2
diyAudio Member
Join Date: Oct 2004
Location: Adelaide South Oz
Some background for your possible interest.

These are 2 of the most commonly quoted articles on CCS circuits. Walt Jung was an engineer at Analog Devices (now retired). These will cover your question.

  Reply With Quote
Old 10th June 2009, 03:01 AM   #3
Bitrex is offline Bitrex  United States
diyAudio Member
Join Date: Jan 2009
Excellent resources, thank you!
  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
Is it an advantage to use this one instead of 2SC5200 or 2SA1943? destroyer X Solid State 8 11th December 2009 04:57 PM
What's the advantage of E-linear Michael Koster Tubes / Valves 34 30th August 2009 01:38 AM
Any advantage of increase VDD to +6V for tda1541a? Sunsun22 Digital Source 4 30th December 2008 03:40 PM
Another advantage of IB mashaffer Subwoofers 2 15th September 2007 04:57 PM
advantage preamp seahag Chip Amps 9 4th October 2005 01:23 AM

New To Site? Need Help?

All times are GMT. The time now is 04:07 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