Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Pass Labs This forum is dedicated to Pass Labs discussion.

DEF Amp
DEF Amp
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 2nd December 2016, 08:51 PM   #1
Nelson Pass is offline Nelson Pass  United States
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
DEF Amp
Default DEF Amp

I am going to start this thread around the circuit shown at BAF 2016,
seen at the end of the talk on the video, and attached here in simplified
form.

I am calling it DEF, which stands for Depletion / Enhancement Follower.
It is a self-biasing push-pull output stage which has some interesting
characteristics, not the least of which is low temperature drift which allows
stable undegenerated operation.

Attached Images
File Type: jpg DEF.jpg (203.4 KB, 4057 views)
  Reply With Quote
Old 2nd December 2016, 08:56 PM   #2
Zen Mod is online now Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
DEF Amp
oh boy ...... here we go again

I'm outa here and outa electronics

not just that I can't keep up with Papamps .......... what's more important - I can't keep up even with just 2% of kwayzee Papawittyness

__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 2nd December 2016, 09:06 PM   #3
Dennis Hui is online now Dennis Hui  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: Toronto, Canada
DEF Amp
Watching this with great interest. Thanks Papa!

Dennis
__________________
We are fearless amplifier builders. A little heat doesn't scare us at all.
- NP 2002
  Reply With Quote
Old 2nd December 2016, 09:07 PM   #4
xrk971 is offline xrk971  United States
Got Foam?
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Metro DC area
DEF Amp
Very cool. Thank you for the new toy Mr Pass.

What parts can you recommend for the interested student to try out at home? The video shows a voltage divider on the gate of the P channel to balance offset. What values go there?
  Reply With Quote
Old 2nd December 2016, 09:21 PM   #5
riksu is offline riksu  Finland
diyAudio Member
 
Join Date: Jul 2015
Location: Here
Superb
  Reply With Quote
Old 2nd December 2016, 09:25 PM   #6
Soundhappy is offline Soundhappy  France
diyAudio Member
 
Soundhappy's Avatar
 
Join Date: Oct 2012
Location: Montpellier near Mediterranean Sea France
DEF Amp
Papa go from Click the image to open in full size. to
__________________
class A amplifiers with full range speakers
sings like angels in heaven
  Reply With Quote
Old 2nd December 2016, 10:03 PM   #7
needtubes is offline needtubes  United States
diyAudio Member
 
Join Date: May 2003
Quote:
Originally Posted by Nelson Pass View Post
...I am calling it DEF...
Eh??

Very interesting, though it will be a challenge to find enhancement P-channels whose Vgs matches that of available depletion parts... The IXYS parts all hang around -2V for reasonable bias (<2A), so maybe the 2SJ201 could work. The USCi and Infineon JFETs all require very negative (<-7V) bias, though. Perhaps, once again, the Semisouth part is just special...
  Reply With Quote
Old 2nd December 2016, 10:36 PM   #8
dimkasta is offline dimkasta  Greece
diyAudio Member
 
dimkasta's Avatar
 
Join Date: May 2010
Location: Athens
Click the image to open in full size.

Thanks for all the fun
__________________
Too many projects... so little time...
  Reply With Quote
Old 2nd December 2016, 10:50 PM   #9
wdecho is offline wdecho  United States
diyAudio Member
 
Join Date: Oct 2014
DEF Amp
Some of you young whizzes fill in the blanks with some available parts and I will build. I already have some heatsinks, 20V transformer and PS section ready to build while waiting the BAF and a buildable project.
  Reply With Quote
Old 2nd December 2016, 11:48 PM   #10
rideht is offline rideht  Germany
diyAudio Member
 
Join Date: Dec 2015
Great, thank you so much, i am interested in this
  Reply With Quote

Reply


DEF AmpHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Multicore CPUs & their desktop boards: Any risk to high def audio quality? oltos Digital Source 0 17th April 2014 07:12 PM
Def Tech Powerfield Supercube II Sub Amp john65b Swap Meet 3 15th May 2013 01:43 AM
Def Tech PF-10 amp lcq1 Subwoofers 1 29th March 2012 03:21 PM


New To Site? Need Help?

All times are GMT. The time now is 07:59 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki