Dual secondaries transformer. - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

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
Reply
 
Thread Tools Search this Thread
Old 17th January 2012, 04:24 AM   #1
diyAudio Member
 
lanchile's Avatar
 
Join Date: Sep 2008
Location: AREA 51
Default Dual secondaries transformer.

I have a dilemma, I am not sure if I am willing to sacrifice capacitance for voltage separation. if I use the one on top, I will get 3.400uf per rail only, but I will get separation in voltage.
if I use the one on bottom I will get more capacitance 13.600uf, but I will have to share voltage for both channels.


PS: Transformer does not have center tap, just dual secondaries.
Attached Images
File Type: jpg 001.JPG (87.0 KB, 152 views)

Last edited by lanchile; 17th January 2012 at 04:27 AM.
  Reply With Quote
Old 17th January 2012, 05:29 AM   #2
diyAudio Member
 
Forman313's Avatar
 
Join Date: Jan 2010
The need for capacistance depends on the application and power.

If its a 2x100-150w 8r amplifier, it would probably benefit more from 10+kuF than channel separation.

How about connecting the two channels in opposite phase?
__________________
Tweak or die!
  Reply With Quote
Old 17th January 2012, 06:38 AM   #3
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
How do you figure 3400 uF per rail, for the top ones? It would give 3400 uF BETWEEN the rails, but 6800 uF from each rail to Gnd. No?

Why not just add four caps to the top ones and be done?

Also, for even better separation, if you can afford it, and have the space, use a whole separate transformer for each channel.

By the way: For both cases, to get the best separation, you would want to be sure to run the two channels' ground conductors separately, from the PSU to each channel's electronics, and only have them connect with each other at the star ground point (probably a short PCB trace stub where all of the grounds connect, which is then connected to the main smoothing caps' ground). If the ground-return currents shared any length of conductor, each channel would induce voltages that could modulate the other channel's ground voltages, at the non-PSU ends of all of the ground-return conductors that were connected "upstream", which could get summed in with the input signal, et al. It's the same reason that star grounding is used. But I figured I'd re-iterate it, since you are concerned about channel separation.

Last edited by gootee; 17th January 2012 at 06:53 AM.
  Reply With Quote
Old 17th January 2012, 07:22 AM   #4
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
You simply don't have a choice, you must use lower schematic. Using upper one you will blown your amp in a few seconds.
  Reply With Quote
Old 17th January 2012, 09:48 AM   #5
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Yes, given two secondaries (no CT) only the lower one will work. To do the top one you need a CT.
  Reply With Quote
Old 17th January 2012, 11:50 AM   #6
diyAudio Member
 
jkuetemann's Avatar
 
Join Date: Dec 2010
Location: Paris, Ontario
Connecting the correct two leads of the secondaries together will effectively produce a centre tap and the transformer can be used with either configuration. A single bridge is a little more voltage efficient but the two bridge solution makes for a quieter ground by reduces the current (reservoir charging pulses) in the ground line.
__________________
---Jason Kuetemann---
When the student is ready, the master appears.
  Reply With Quote
Old 17th January 2012, 11:55 AM   #7
diyAudio Member
 
Join Date: May 2003
Location: quebec
please draw transformer windings, then it will be possible to comment
  Reply With Quote
Old 17th January 2012, 08:46 PM   #8
diyAudio Member
 
lanchile's Avatar
 
Join Date: Sep 2008
Location: AREA 51
Thank you guys! My toroidal transformer is 300vac 32vac X 2. it does not have a center tap.it is from old Adcom amplifier that I savaged for parts. I guess I will have to stick to the one on the bottom. I wanted to do it this way but this transformer has a Center Tap and mine does not!!!!
Attached Images
File Type: gif Dual-Power-Supply-Circuit.gif (3.6 KB, 73 views)
  Reply With Quote
Old 18th January 2012, 02:43 AM   #9
CBS240 is offline CBS240  United States
diyAudio Member
 
CBS240's Avatar
 
Join Date: Aug 2005
Location: K-town
2 secondaries connected in series (correct polarity of course) will produce a single secondary with a center tap. 2 secondaries gives you more options.
__________________
All the trouble I've ever been in started out as fun......
  Reply With Quote
Old 18th January 2012, 02:48 AM   #10
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
Quote:
Originally Posted by CBS240 View Post
2 secondaries connected in series (correct polarity of course) will produce a single secondary with a center tap. 2 secondaries gives you more options.
Correct. Dual identical secondaries gives you more options than a plain centertap, not fewer.

If you join the secondaries in the center, then it IS a centertap.

Last edited by gootee; 18th January 2012 at 03:15 AM.
  Reply With Quote

Reply


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
OOPS! bought transformer without dual secondaries ByronInPortland Chipamp 7 6th May 2011 04:28 PM
UTC A-43 transformer - advantage in parelleling dual secondaries? sharpi31 Parts 0 14th July 2009 04:18 PM
One transformer with 4 secondaries or two transformers with dual secondaries Baka Chip Amps 5 28th November 2008 06:39 AM
Wanted: Transformer 22-25 VAC Dual Secondaries - Toroid or other DSchmidt Swap Meet 4 3rd January 2006 09:04 PM
Transformer Dual Primaries/Secondaries cantskienuf Parts 6 18th July 2005 08:09 PM


New To Site? Need Help?

All times are GMT. The time now is 02:06 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2