1 trafo for 2 snubberized 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 21st December 2005, 12:52 PM   #1
diyAudio Member
 
Join Date: Nov 2004
Location: UK, bristol
Default 1 trafo for 2 snubberized bridges ?

Can one dual secondary trafo be used with 2 brianGT snubberized boards?

Or would it need to have 4 secondaries ?

This question implies an assumption that 2 snubber boards are better than 1. If that is right? then a follow up question is whether 2x say 20000uF snubberized boards is better than 1x 40000uF board?
  Reply With Quote
Old 22nd December 2005, 07:28 AM   #2
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
connect the two secondary wires to each pair of ~ bridge connectors.
This will give you two DC outputs. You can then run two independant DC PSUs to your loads. Not quite as good isolation as 4 secondaries, but much better than a shared PSU for a stereo amp. You are starting to go down the dual mono route but using the cheap method.

Connect the transformer central common to the power ground and run both the PSU capacitor commons back to the same power ground. Try to keep the layout to ensure all the power ground wires are fairly short. Then run a wire from power ground to your Central Star Ground (CSG). Do not combine the power ground with the CSG!!!!
__________________
regards Andrew T.
  Reply With Quote
Old 15th January 2006, 05:37 PM   #3
diyAudio Member
 
Join Date: Nov 2004
Location: UK, bristol
This is the chipamp snubber board. http://www.chipamp.com/images/ps.gif

So let's say I've got 2 of these running off one pair of 25V secondaries.

Is it ok to connect an amp to just one board and leave the other connected but not being used?

How much power would the unused snubber board draw?

Thanks.
  Reply With Quote
Old 16th January 2006, 07:05 AM   #4
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
delete the AC2 and make connections from AC1 to the empty ~ bridge inputs.
The unused PSU will draw a big power pulse on start up then draw very little current afterwards. 2k2 + electro leakage = very low power.

Has anyone on the thread queried the value of the 2k2 resistor. It seems excessively low.

You may benefit from adding snubbers to each of the diodes.
__________________
regards Andrew T.
  Reply With Quote
Old 16th January 2006, 09:36 AM   #5
diyAudio Member
 
Join Date: Nov 2004
Location: UK, bristol
OK thanks. So I'm using 1 secondary to feed both rectifiers on the 'snubber' board (and the other secondary to drive my other board).

There was good Intro to rectification on someones diy audio site but I can't lay my hands on it now, I think that would have covered these questions.
  Reply With Quote
Old 16th January 2006, 10:32 AM   #6
hates ground loops
diyAudio Member
 
Rodeodave's Avatar
 
Join Date: Dec 2004
Location: in the alps
Blog Entries: 1
Hi,

my situation: One Trafo with one secondary. What's better for powering two channels:

two bridge-rect. with CLC (Cap-Inductor-Cap) filter each or
one bridge-rect. with CLCLC filter with the two channels sharing the supply.

Greets, Dave
__________________
Gravity - Making the G since 13.7 billion B.C.
  Reply With Quote
Old 16th January 2006, 02:44 PM   #7
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi Jimbo,
OOPS I slipped up. I forgot you need bipolar supplies.

Connect the two secondaries in series. Take the top connection to ~ bridge and take the bottom to the other ~ bridge. Now take the same two secondary connections to the other bridge.
Connect both the capacitor commons back to the transformer centre tap. Connect the centre tap to your central star ground.
Now you have two PSUs that can feed two channels of power amp.
__________________
regards Andrew T.
  Reply With Quote
Old 16th January 2006, 06:16 PM   #8
diyAudio Member
 
Join Date: Nov 2004
Location: UK, bristol
Does it matter which ends of the secondaries I connect? In which case I would need to examine the trafo or get info from the manufacturer.
  Reply With Quote
Old 17th January 2006, 07:05 AM   #9
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
YES, it matters.
Connect the secondaries in series and measure the voltage on the two spare ends.
If you have two times the secondary voltage then the windings are in phase and you can then connect into your PSU circuit.

If you measure almost zero volts then the secondaries are out of phase and you must swap around one pair of secondary connections.

After you have the correct voltage on the series connected secondaries, it then does not matter which ends are connected to the bridge~ since both bridge inputs can accept either AC connection.
__________________
regards Andrew T.
  Reply With Quote
Old 19th February 2006, 12:06 PM   #10
diyAudio Member
 
Join Date: Nov 2004
Location: UK, bristol
So, I'm finally about to build.

If I follow the advice above, ie series connect my secondaries and connect to bridge, aren't I going to get twice the voltage I wanted out from the bridge? I've got 25V secondaries.

If we go back to the start > Is there anything wrong with connecting the two power supply boards in parallel, ie my four secondary wires are paralleled to the same point on each PS board http://www.chipamp.com/images/ps.gif
  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
2 or 4 bridges? Raka Chip Amps 26 29th July 2012 01:53 PM
Power supply options.. bigger trafo with less caps or medium trafo with heavy caps? rhythmdiy Chip Amps 9 23rd October 2007 12:30 AM
tda2030, bridges vlljpior Chip Amps 2 29th September 2006 06:54 AM
Bridges for life ! mpmarino Parts 4 11th December 2004 10:11 PM
Why two bridges are better than one? Andypairo Pass Labs 14 15th October 2002 12:25 AM


New To Site? Need Help?

All times are GMT. The time now is 02:00 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