Single transformer - multiple bridges! - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 4th February 2012, 08:22 AM   #1
UV101 is offline UV101  England
diyAudio Member
 
UV101's Avatar
 
Join Date: Dec 2008
Location: Oxford
Default Single transformer - multiple bridges!

Does this work? I see no reason why not on paper.

What I mean is if we have a transformer winding. Can we run multiple independent rectification (i.e. ac inputs in parallel) to generate multiple isolated dc supplies with a common ground?

Would we see any adverse effects?
__________________
When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
JA-88D Class A, Audio Aero Capitole MKII, Focal and Kimber "Leave Nothing as Standard"
  Reply With Quote
Old 4th February 2012, 08:29 AM   #2
jazz is offline jazz  Netherlands
diyAudio Member
 
Join Date: Dec 2001
Location: leiden, physically that is...
Hi,

It's what i use in one of my tube amps and it works fine.

grtz
Joris
__________________
oh, what a beautifull day
I wanna go out and play!
  Reply With Quote
Old 4th February 2012, 08:35 AM   #3
diyAudio Member
 
sofaspud's Avatar
 
Join Date: Nov 2005
Location: San Antonio
It can be done, yes, but if they share a common ground are they really isolated?
Coincidentally, I'm currently working with a recycled linear supply whose single transformer provides 25VDC through a full-wave bridge rectifier and 12VDC through a half-wave diode circuit.
__________________
It is error only, and not truth, that shrinks from enquiry. - Thomas Paine
  Reply With Quote
Old 4th February 2012, 10:07 AM   #4
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
You need just one bridge, and then a single diode for each additional supply. However, they won't be fully isolated from each other.
  Reply With Quote
Old 4th February 2012, 10:17 AM   #5
UV101 is offline UV101  England
diyAudio Member
 
UV101's Avatar
 
Join Date: Dec 2008
Location: Oxford
Thanks. With respect to the common ground, even if I use multiple transformers, I'd need to common the ground for rails in the same device.

What I'm looking to achieve is to replace the multiple 5v psu's with individual transformers I run inside my player with a much larger single transformer hence the multiple full wave bridges from a single winding and keep the separation for each supply back to the bridge (common gnds accepted).

I wonder if the multiple transformers is adding anything or if a single higher quality higher va unit will be as good. I'm not looking to reduce the number of rectifiers, smoothers, regs etc.
__________________
When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
JA-88D Class A, Audio Aero Capitole MKII, Focal and Kimber "Leave Nothing as Standard"
  Reply With Quote
Old 4th February 2012, 10:26 AM   #6
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Would it help to have one transformer with multiple windings?
These are then isolated from each other. Can be rectified and smoothed separately. Regulated if need be.

Then each circuit can have only ONE final connection to your common voltage reference.
__________________
regards Andrew T.
  Reply With Quote
Old 4th February 2012, 10:47 AM   #7
diyAudio Member
 
Join Date: Oct 2011
Location: Tauberbischofsheim, Germany
Hi,

if common gnd is acceptable, you don't need a full bridge for each positive line. You'd just feature a bridge capable for the total current amount, plus two diodes, or a double diode with common cathodes from the AC terminals to each pos. rail.

Best regards!
  Reply With Quote
Old 4th February 2012, 10:59 AM   #8
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Most of any problems will be with the grounds. Much easier to have either one big PSU to supply the lot, or lots of genuinely separate PSUs driven from separate secondaries - doesn't have to be separate transformers. 'Separate' PSUs driven from one secondary is about the hardest way to do it. My feeling is that if you knew enough about ground wiring to get it right, you would know enough not to attempt it!
  Reply With Quote
Old 6th February 2012, 09:35 PM   #9
UV101 is offline UV101  England
diyAudio Member
 
UV101's Avatar
 
Join Date: Dec 2008
Location: Oxford
What I have is this
Click the image to open in full size.

And I'm wondering what will happen if I move the this
Click the image to open in full size.

I am already dealing with multiple grounds so I've no issue there. Obviously I could got for a transformer with multiple secondary windings and keep that side as per the 1st diagram and the mains side as per the second, but I wonder how using an off the shelf large va transformer would effect things.

I treat each supply as being in its own noise domain but I wonder if going all the way back to the secondary windings is really necessary. I'm not just looking for an it will work or wont, I'm interested in opinions on the quality of the supply.....

I appreciate the comments so far, thanks ;-)
__________________
When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
JA-88D Class A, Audio Aero Capitole MKII, Focal and Kimber "Leave Nothing as Standard"
  Reply With Quote
Old 6th February 2012, 09:39 PM   #10
UV101 is offline UV101  England
diyAudio Member
 
UV101's Avatar
 
Join Date: Dec 2008
Location: Oxford
Quote:
Originally Posted by DF96 View Post
You need just one bridge, and then a single diode for each additional supply. However, they won't be fully isolated from each other.
Somehow missed this!!!! Same question applies, how will this effect things compared to individual secondary's?
__________________
When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
JA-88D Class A, Audio Aero Capitole MKII, Focal and Kimber "Leave Nothing as Standard"
  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
Two bridges and a CT transformer.... rsumperl Tubes / Valves 27 29th June 2011 11:10 AM
Single Transformer for multiple TDA1554Q pra3718 Chip Amps 9 15th December 2010 11:56 AM
Multiple Speakers with single reciever DerFarm Parts 2 29th April 2010 04:56 PM
Multiple inputs for single output tommy_o Analog Line Level 7 13th November 2009 08:01 PM
Single Tumult or multiple others? DIYNewbie Multi-Way 12 22nd June 2004 08:27 PM


New To Site? Need Help?

All times are GMT. The time now is 10:11 AM.


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