# Connecting Dual Torroidals



## Pancakes (Jan 16, 2008)

Not sure if this is the right place to post this but I figure people with their noses in this forum will know the answer to my question.

I'm building a power amp and am stumped with the Torroidals. There are 4 outputs (split centre tap), that mush is easy. Both the inputs are orange and I want the ripple to be in phase on both L and R channels.

I'll be splitting the mains AC after the first fuse > L and R Torroidals > 2 x 35A 400V bridge rectifiers/channel (One will supply +V rail the other -V rail, the unused connections will be joined then run to ground.

I'm picturing that if I connect one of the cores up different to the other that it will reverse the 0V and +V secondaries too? I have access to an oscilloscope to check the output phasing (is it even phasing?).

Thanks in advance! Brian.


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## lcaillo (May 2, 2006)

Not sure what you mean exactly by "connect one of the cores up different to the other " but you may find some help here:

http://www.electro-dan.co.uk/electronics/wiringtrans.html


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## Pancakes (Jan 16, 2008)

So each of my transformers is like the 230V single primaries/series secondaries illustration on the site you linked to (the bottom left of the four. The question is that I have two of those and am worried that if I hook one of them up as shown but the other with the primaries reversed (mine are both orange on each core so no live and neutral markings to indicate the start and finish of each primary winding). Does that mean that the +V and 0V of the secondary pairs (in the illustration red/yellow and blue/grey) will be reversed also or will it not matter after the rectifiers anyway?


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## lcaillo (May 2, 2006)

Changing the polarity of the primary does not affect the d.c. output of your rectifier circuit. The orientation and relationship of the rectifiers and filters determine the polarity of the d.c. output.


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## Pancakes (Jan 16, 2008)

Yeah that finally came to me as I was going to sleep. Now I get it I can't beleive I got stuck on that! I guess doing stuff with 12vDC forever and no AC has bunged me up. How embarressing to have asked that and thanks for the polite reply!


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## lcaillo (May 2, 2006)

You should not be embarrassed at all to ask. We all get a bit mixed up on basics every now and then. The discussion may help someone else understand how transformers and rectifiers work.


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