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

Look ma, no center tap
Look ma, no center tap
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 13th April 2015, 05:23 PM   #1
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Look ma, no center tap
Default Look ma, no center tap

Retrofitting an LM4780 chip amp into an old Fisher Console -- no CT on the power transformer. This works as a rail-splitter for a more demanding load:
Attached Images
File Type: png RailSplitter.png (38.6 KB, 355 views)
  Reply With Quote
Old 14th April 2015, 02:33 PM   #2
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Are you sure? What do the upper three diodes do? As wired, not what the lower three diodes do!
  Reply With Quote
Old 14th April 2015, 02:50 PM   #3
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: The great city of Turnhout, BE
Jack, the real test here is with asymmetrical loads. Load it so that the pos side needs, say, 3A and the neg side 0.3A Then see what happens.

Jan
__________________
Cable: a potential source of trouble interconnecting two other potential sources of trouble - Erik Margan
Linear Audio pubs and articles . The SilentSwitcher now at diyaudio store SilentSwitcher. Keeping in touch with SY.
  Reply With Quote
Old 14th April 2015, 03:02 PM   #4
wwenze is offline wwenze  Singapore
diyAudio Member
 
Join Date: Mar 2008
A rail splitter is essentially an amplifier that outputs a "nothing"

Or, you can run your LM4780 in bridged mode so that negative terminal can output something more useful. That's how the cheap stuff are powering their speakers, because bipolar supplies are expensive.
  Reply With Quote
Old 14th April 2015, 07:29 PM   #5
Ketje is offline Ketje  Belgium
diyAudio Member
 
Ketje's Avatar
 
Join Date: Dec 2012
Location: Flanders
Quote:
Originally Posted by jackinnj View Post
Retrofitting an LM4780 chip amp into an old Fisher Console -- no CT on the power transformer. This works as a rail-splitter for a more demanding load:
The datasheet of the LM4780 shows how to use it with a single supply.
Mona
Attached Images
File Type: jpg AmpNo0.jpg (67.7 KB, 284 views)
  Reply With Quote
Old 16th April 2015, 06:31 AM   #6
palstanturhin is offline palstanturhin  Finland
diyAudio Member
 
palstanturhin's Avatar
 
Join Date: Jun 2011
Virtual ground.
Attached Images
File Type: png LM1875_VGND.png (3.9 KB, 223 views)
  Reply With Quote
Old 21st April 2015, 07:04 PM   #7
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Look ma, no center tap
Quote:
Originally Posted by jan.didden View Post
Jack, the real test here is with asymmetrical loads. Load it so that the pos side needs, say, 3A and the neg side 0.3A Then see what happens.

Jan
How about a nice muscular servo? Are you hinting at Figure 2 of LA#9's article "Low Parts Count Amplifier"?
  Reply With Quote
Old 21st April 2015, 07:27 PM   #8
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Look ma, no center tap
Quote:
Originally Posted by jackinnj View Post
Retrofitting an LM4780 chip amp into an old Fisher Console -- no CT on the power transformer. This works as a rail-splitter for a more demanding load:




-RNM
  Reply With Quote
Old 27th April 2015, 06:09 PM   #9
Binely is offline Binely  United States
diyAudio Member
 
Binely's Avatar
 
Join Date: Mar 2015
Location: St. Louis, Missouri
I have an old fisher tuner I would be interested in retrofitting too. Uses a couple of old sanyo IC's. Interested in collaborating?
  Reply With Quote

Reply


Look ma, no center tapHide 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
Half B+ taken from center tap kaputt Power Supplies 4 14th August 2014 12:31 PM
Center tap or not... ixe13 Tubes / Valves 7 8th April 2011 11:14 PM
Center tap wiring tom wesley Chip Amps 3 11th July 2010 07:34 PM
No center tap Help FastEddy Power Supplies 57 19th April 2010 07:01 PM
Transformer Center Tap dswiston Parts 2 4th February 2004 03:09 PM


New To Site? Need Help?

All times are GMT. The time now is 11:46 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki