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

Solid State Talk all about solid state amplification.

beginners q's
beginners q's
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 23rd May 2005, 11:03 AM   #1
lt cdr data is offline lt cdr data  Wales
diyAudio Member
Join Date: Dec 2003
Location: earth
Default beginners q's

input diff pair is SO common, why not simple single transistor with feedback to the emitter? (current feedback)

And which is best, double or triple darlington OPS for BJTs?
  Reply With Quote
Old 23rd May 2005, 02:41 PM   #2
anatech is offline anatech  Canada
diyAudio Moderator
anatech's Avatar
Join Date: Jun 2004
Location: Georgetown, On
beginners q's
Hi cdr data,
NAD used a single bjt input instead of a diff pair. This design does not compete well sonically with other approaches. If it did, that would be the prevailing design. The diff pair can be far more linear, over a greater input signal range. It is self balancing for DC offset and there is no DC offset between the error input and signal input (0.6V for the single bjt).

There are enough variations between input device types and configurations to keep one busy for an awfully long time. At least you are on ground that is proven and stable.

You have only listed a couple output configurations. Lots of different ways to do things here too.

The answers depend one what you intend at the end, and cost. One circuit may not fit all situations.

  Reply With Quote
Old 23rd May 2005, 07:20 PM   #3
AndrewT is offline AndrewT  Scotland
Join Date: Jul 2004
Location: Scottish Borders
single input transistor is reputedly quieter than LTP.
JLH and many others use it.
The single will probably be more difficult to stabilise the DC offset at the output but I have never yet seen a design using a DC servo to control that parameter.
Swot up on it and give us a new design.
regards Andrew T.
  Reply With Quote
Old 23rd May 2005, 09:59 PM   #4
boraomega is offline boraomega  Serbia
diyAudio Member
Join Date: May 2005
Location: Cacak, Serbia
Try this address: http://sound.westhost.com/amp_design.htm
Rod Elliot is well known audio master. You might find some answers there.
  Reply With Quote


beginners q'sHide 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
Impedance for beginners jzagaja Multi-Way 6 15th December 2008 04:39 PM
Spice for beginners? Onvinyl Solid State 19 10th December 2007 11:09 AM
F2 for beginners vitalstates Pass Labs 6 24th January 2007 12:02 AM

New To Site? Need Help?

All times are GMT. The time now is 10:43 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio