Transformer output in phase and out of phase

Hi everyone,

Can someone please explain to me the following principle:

I own an Electrocompaniet Ampliwire IIA amplifier and I am working on improving the power supply.

That transformer used has four secondary outputs per side and when checking the phase of the windings I discovered that two of the windings per side are out of phase.

I first thought that someone before me had modified the amplifier and had by accident wired some out of phase,
but after checking several other amps I discovered that it appears to have been manufactured that way.

I always thought that a transformer should be connected in phase, where comes my surprise in discovering this.

Does anyone have a logical explanation for a connection to a bridge rectifier that two of the four windings are out of phase with each other?
What are the advantages and disadvantage either one way or another?

Thank you in advance for any response you may have that would enlighten me.

I include a wiring diagram showing how the windings are connected on each bridge rectifier.
 

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Hi everyone,

Can someone please explain to me the following principle:

I own an Electrocompaniet Ampliwire IIA amplifier and I am working on improving the power supply.

That transformer used has four secondary outputs per side and when checking the phase of the windings I discovered that two of the windings per side are out of phase.

I first thought that someone before me had modified the amplifier and had by accident wired some out of phase,
but after checking several other amps I discovered that it appears to have been manufactured that way.

I always thought that a transformer should be connected in phase, where comes my surprise in discovering this.

Does anyone have a logical explanation for a connection to a bridge rectifier that two of the four windings are out of phase with each other?
What are the advantages and disadvantage either one way or another?

Thank you in advance for any response you may have that would enlighten me.

I include a wiring diagram showing how the windings are connected on each bridge rectifier.
That schematic makes no sense, did you draw it?

What is the outside load?

Are +/- outputs connected in some way?

Where is Ground?

WHY would anybody make same colour coding wire pairs different phase?

It makes no sense at all.

Side note: answering "go read some (unspecified) book" is a useless answer ; can YOU answer the question?

Same as "google it" or "there is some YT video explaining it" without further details.

Otherwise it only calms some obsessive compulsion to "write something" ... no matter what.
 
My goal was not to draw the entire PSU, but only the connections to the Diode Bridge to show that two secondaries were plugged in out of phase. Only that.

Forget how primary is connected to the mains, it's not important, just that it's plugged in parallel, and for the ground, it's the four black wires plugged in together.

No, it was not me who chose the colors of the transfo wires

yes, there are capacitors after the diode bridges, which I did not draw, that was not the purpose of the exercise.
 
Wiring half the transformer "in- phase" will result in 50/60 Hz supply ripple and twice the DC ripple amplitude than normal "push-pull" wiring that gives you 100/120Hz ripple. Normally you get a center tapped winding instead of two separate winding, which is impossible to get wrong. The transformer center tap is grounded which creates two independent positive and negative DC voltages. Typical amplifiers require two independent voltages, positive and negative so that large DC blocking capacitors are not required to connect the speaker, which provides better bass frequency response and avoids the potential distortion generated by the large electrolytic capacitors.
 
My goal was not to draw the entire PSU, but only the connections to the Diode Bridge to show that two secondaries were plugged in out of phase. Only that.

Forget how primary is connected to the mains, it's not important, just that it's plugged in parallel, and for the ground, it's the four black wires plugged in together.

No, it was not me who chose the colors of the transfo wires

yes, there are capacitors after the diode bridges, which I did not draw, that was not the purpose of the exercise.
Please post the full schematic, from mains plug to power rails.

Your verbal explanation is not clear enough.
 
As I said in my first post, my goal was to replace the PSU inside the amplifier, with a better one. And it brought a huge improvement in the sound.

It was when I removed the old one and analyzed it that I discovered that there were secondary windings connected out of phase and this thanks to mr. Mark Johnson's PhaseDots circuit.

And since I'm curious, that's why I asked what the benefit of connecting these out-of-phase secondaries might be, nothing more.

You can be sure that I checked twice that I had not made any mistakes when I checked the polarity of the winding.
 
All of the green leads will have the same polarity/phase wrt the black leads.
There are errors in the schematic. To form a center tap with two of the windings,
a green lead must be connected to a black lead, and then both to ground.
 
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Normally, I will 100% agreed with you Rayma,

But in my amplifier's supply, the two green wires are connected to the diode bridge and the two black wires are connected to the ground.
And it's when I connected those windings to the PhaseDots circuit, I discovered that the number two and four secondaries are out of phase to the rest of the transformer

Normaly, the first green wire is supposed to be connected to the bridge, the first black et the second green wire connected together for the ground, and finally the second black wire to the bridge.

But this not what I have in my amp
 
The two wires going to each bridge must have opposite polarity/phase to get DC out of the rectifier.
If they were the same polarity/phase, the diodes would not conduct.

In your diagram, the dots are correct, but the colors are wrong. The wires with dots should all be the same color.
Also the connection joining all the black wires together should be grounded.

Is the transformer manually wired from terminals on it, or are the wires captive to the transformer?
 
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Okay, I have found the problem.

I had starting with the idea that all secondary green wires must be the first one. If I invert the second and the fourth winding, all become in phase

The schematic and the circuit will work now.

Thanks rayma, you had help me when you have talking about the dot and the color of the wire. This transformer have the dot associated with different color for the phase. It's the only possible explanation
 

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