Phase

[Patdel]

Before Linn had a convention for live phase on the power cord. Which of the two metal pins in the picture of a power cord should be connected to live in the socket?

[Tendaberry]

I don't think you can say for which of the metal pins. However, if you connect the cable to the wall, you should have the live phase to the right at the other end.

[V.A.MKD]

I don't think you can say for which of the metal pins. However, if you connect the cable to the wall, you should have the live phase to the right at the other end.

Yes, absolutely ...

[Spannko]

Can someone please explain the mechanism by which mains phase affects sound?

EDIT: I’ve just found this http://whatishifi.blogspot.com/2017/05 ... phase.html. It appears that correct polarity can make a huge difference to circulating earth currents, but the mechanism by which it occurs remains a mystery! Are we looking at unintentional inductive connections?

[lejonklou]

Can someone please explain the mechanism by which mains phase affects sound?

There are several mechanisms involved and which ones are relevant depends on how the power supply is designed.

The easiest to grasp and measure is when linear transformers are used. Live on the outermost winding and neutral on the innermost creates an electrical field around the transformer. Reverse the two and the neutral outer winding will shield the inner live ones, resulting in a weaker field.

With switch mode power supplies it often comes down to a handful of details, which are more difficult to grasp and measure, but can nevertheless be heard.

[Patdel]

I don't think you can say for which of the metal pins. However, if you connect the cable to the wall, you should have the live phase to the right at the other end.

With ground up I suppose. Thanks! That's what I have now. 50% chance! Haven't compared though.

It's the lower pin that should go into live phase then

[matthias]

There are several mechanisms involved and which ones are relevant depends on how the power supply is designed.
The easiest to grasp and measure is when linear transformers are used. Live on the outermost winding and neutral on the innermost creates an electrical field around the transformer. Reverse the two and the neutral outer winding will shield the inner live ones, resulting in a weaker field.
With switch mode power supplies it often comes down to a handful of details, which are more difficult to grasp and measure, but can nevertheless be heard.

Hi Fredrik,
just came across this old thread.
Did you find a pattern for best musicality when connecting linear transformers?
Is it better to have "Live" on the innermost or the outermost winding?
Thank you

[lejonklou]

Hi Matt!

As I mentioned in the post you quoted, it is usually better to have the live phase on the inner end of the wiring in a conventional linear mains transformer.

[Spannko]

I’m struggling to understand what the innermost and outermost windings are Fredrik. Could you explain please.

[lejonklou]

It depends on how the transformer (or inductor) is wound. If there is an inside and an outside, and the wires are long and wound in several layers, you have one end of the wire that starts closer to the inside and another end that ends closer to the outside. That's looking at one winding.

If you have a transformer (or inductor) with a winding that isn't several layers but only one, you will have often have one end of the wire connected to the signal and the other connected to ground. Then the end where the signal is connected will have a stronger electrical field around it than the other end. So then it becomes a matter of which side is closer to components that are sensitive to this field.

But if you remove the transformer (or inductor) far from the sensitive electronics, you will still hear a difference between which end of the wire you connect to signal and which you connect to ground. Is it mainly because the wire has some directionality, are there mechanical factors involved or is it due to changes in magnetic flux in the core? I don't know enough about what exactly happens in the core.

[Spannko]

Ah, right. I understand what you’re saying now. I wondered if you were describing a multi-layer secondary winding. For similar reasons Audience mark their Auricap bipolar to signify which wire is connected to the outside foil. They suggest connecting the outside foil to the lowest impedance connection for maximum noise suppression.

A typical power transformers primary winding will have 2 to 3 layers of wire, so is it important that the outermost winding (of the primary) is connected to the mains neutral? Hopefully, there’s a convention which requires the blue neutral wire (on the transformer) to be connected to the outermost wire. So winding starts with a red wire and ends with a blue wire? This makes sense from a safety point of view too, so I’d be surprised if they’re not made this way.

If I’ve understood correctly, this also explains why it’s important to get the mains polarity correct in countries where the mains plug can be connected with either polarity?

Something you haven’t mentioned is the importance (or not!) of the polarity of the transformers output wrt it’s input, for transformers with only one secondary winding (which I think is usually only one layer thick). I’m having a think about this one!

Now I’m struggling with your second paragraph! The idea that the electrical field varies along a wires length?