Jump to content

jeromelang

Why does ac polarity affect sound quality?

Recommended Posts

Posted (edited)

Yes, why? Anyone has answers?

 

What's your subject experiences?

 

 

Edited by jeromelang

Share this post


Link to post
Share on other sites

That's a provocative post, jl.  :)  All the usual suspects will tell you that it can't possibly matter, as the mains is AC - but I became a believer after reading Clark Johnsen's excellent book "The Wood Effect" about 20 years ago.

 

Although that book is mainly about how absolute polarity affects the sound, it mentions ac mains polarity as causing similar sonic artefacts to absolute polarity.  So ever since then I make sure that the mains traffo primary circuit is connected "the right way round" wrt Active & Neutral, in any amp I build.

 

AIUI, there is capacitative coupling between primary & secondary windings, which changes with AC orientation.

 

Andy

 

Share this post


Link to post
Share on other sites

AC polarity changes at 50 times/second (L wrt N). Or do you mean phase? Anyway, I wouldn't worry about it to much, your bridge rectifier is smart enough to route the polarity as it changes.

Share this post


Link to post
Share on other sites

If you are talking mains electricity, it's important (not because of polarity as such) but because of rules and regulations, and safety.

Our mains is of the MEN (Multiple Earthed Neutral) type.

The brown wire (old colour was red) is the Active wire. This is the wire that should be switched when a single pole switch is used.

The blue wire (old colour was black) is the Neutral wire. This and the brown (active) wire are the pair that supply the electricity. This is where out 230V is measured and deliverd. The blue (neutral) wire is earthed to a bus bar at the switchboard.

 

This is what people mean when they say a socket/plug/extension is incorrectly wired, that the active and neutral are transposed. It doesn't mean the polarity is wrong, just that standards and safety are compromised.

 

The electricity is AC and the polarity reverses 50 times per second, so there is no absolute polarity.

Share this post


Link to post
Share on other sites


7 minutes ago, pwstereo said:

If you are talking mains electricity, it's important (not because of polarity as such) but because of rules and regulations, and safety.

Our mains is of the MEN (Multiple Earthed Neutral) type.

The brown wire (old colour was red) is the Active wire. This is the wire that should be switched when a single pole switch is used.

The blue wire (old colour was black) is the Neutral wire. This and the brown (active) wire are the pair that supply the electricity. This is where out 230V is measured and deliverd. The blue (neutral) wire is earthed to a bus bar at the switchboard.

 

This is what people mean when they say a socket/plug/extension is incorrectly wired, that the active and neutral are transposed. It doesn't mean the polarity is wrong, just that standards and safety are compromised.

 

The electricity is AC and the polarity reverses 50 times per second, so there is no absolute polarity.

The highlighted  is So important! 

Share this post


Link to post
Share on other sites

Changed the subject title.... 😁

Share this post


Link to post
Share on other sites
Posted (edited)
5 hours ago, andyr said:

That's a provocative post, jl.  :)  All the usual suspects will tell you that it can't possibly matter, as the mains is AC - but I became a believer after reading Clark Johnsen's excellent book "The Wood Effect" about 20 years ago.

 

Although that book is mainly about how absolute polarity affects the sound, it mentions ac mains polarity as causing similar sonic artefacts to absolute polarity.  So ever since then I make sure that the mains traffo primary circuit is connected "the right way round" wrt Active & Neutral, in any amp I build.

 

AIUI, there is capacitative coupling between primary & secondary windings, which changes with AC orientation.

 

Andy

 

I first heard about this ac polarity debacle way back in 1996. back then I was managing a retail store selling pro audio equipments - mixers, compressors, ADAT machines, studio monitors, keyboards, workstations, and so on. An engineer type person came in one day to pick up a processor box or something. He tooked a look at the 2-prong ac plug on the captive ac cord, and said something like: "...oh well, i guess i'll just have to check it then..." I asked him check what, and that was when he told me all about the ac polarity thingy.

 

I went home and checked it on my Alessis Matica 900 power amp, and sure enough there was audible sonic changes when I tried it both ways. The amp came supplied with a captive powercord terminated with a 2-pin European round body plug. I could get it right/wrong either way. Looking back, I think I must have chosen to use the wrong direction - because from then on, the sound image became very upfront, very in-my-face, the whole soundstage was always in front of the NS-1000M speakers (which was how I preferred it at the time).

 

Edited by jeromelang

Share this post


Link to post
Share on other sites

Aside from safety, potentially (pardon the pun) transformer performance.

Share this post


Link to post
Share on other sites


3 hours ago, pwstereo said:

If you are talking mains electricity, it's important (not because of polarity as such) but because of rules and regulations, and safety.

Our mains is of the MEN (Multiple Earthed Neutral) type.

The brown wire (old colour was red) is the Active wire. This is the wire that should be switched when a single pole switch is used.

The blue wire (old colour was black) is the Neutral wire. This and the brown (active) wire are the pair that supply the electricity. This is where out 230V is measured and deliverd. The blue (neutral) wire is earthed to a bus bar at the switchboard.

 

This is what people mean when they say a socket/plug/extension is incorrectly wired, that the active and neutral are transposed. It doesn't mean the polarity is wrong, just that standards and safety are compromised.

 

The electricity is AC and the polarity reverses 50 times per second, so there is no absolute polarity.

 Good advice indeed, explained here, is what can happen when polarity is swapped:   https://sound-au.com/articles/mains-safety.htm

 

"

Connecting Class 2 And Earthed Appliances To Each Other
Although prohibited by the rule: 'Class II - do not earth', linking Class II and earthed items of audio and video gear is done routinely via the shielding on signal carrying cables.  Though users enjoy a great bonus by eliminating ground loop hum, doing this eliminates all the safety advantages of Class II and allows for a horrific possibility.

A potentially lethal hazard occurs if ever an earthed appliance in such a system becomes live on its chassis or internal ground circuit – the fault condition will then pass the full AC supply voltage onto the exposed metalwork of each and every Class II item in the system.

As shown in Figure 6, this can happen merely because a miswired but quite functional supply lead (IEC or hard wired) is used with an AC outlet that has the otherwise harmless error of reversed Active and Neutral.

While the following may seem unlikely, most service techs will have seen similar scenarios with mains leads that have been 'repaired' by unskilled people.  Reversed active and neutral are surprisingly common, especially in older houses and venues, or where unskilled people have performed 'upgrades' to existing wiring.  Not everyone is capable of following simple colour codes and/ or identifying which lead is which in an installation (compounded by older wiring using different colour codes).

Figure 6
Figure 6 - Correct & Incorrect Wiring (Australian Mains Fittings Shown)

The incorrectly wired plug shown will work more-or-less 'normally' in a correctly wired outlet, but it will trip the safety switch - if one is present.  Without a safety switch, it's probable that no-one would ever realise that the lead is miswired unless a tester is routinely used to verify that all leads used are wired properly.  While this might happen with a touring band, it most certainly will not happen in a private residence, and the fault will go un-noticed until a miswired outlet is used.  The combination is then deadly.

 

While I've shown an Australian mains outlet and plug, the same principles apply worldwide.  It's nothing to do with the style of the connectors used, only the way they are wired. "

 

 

Share this post


Link to post
Share on other sites
32 minutes ago, jeromelang said:

I first heard about this ac polarity debacle way back in 1996. back then I was managing a retail store selling pro audio equipments - mixers, compressors, ADAT machines, studio monitors, keyboards, workstations, and so on. An engineer type person came in one day to pick up a processor box or something. He tooked a look at the 2-prong ac plug on the captive ac cord, and said something like: "...oh well, i guess i'll just have to check it then..." I asked him check what, and that was when he told me all about the ac polarity thingy.

 

I went home and checked it on my Alessis Matica 900 power amp, and sure enough there was audible sonic changes when I tried it both ways. The amp came supplied with a captive powercord terminated with a 2-pin European round body plug. I could get it right/wrong either way. Looking back, I think I must have chosen to use the wrong direction - because from then on, the sound image became very upfront, very in-my-face, the whole soundstage was always in front of the NS-1000M speakers (which was how I preferred it at the time).

 

 

The second time when i encountered this issue, I had already changed my job, and was flying around the world making demonstration to distributors with a myriad of audio only and av products. The company's chief engineer had come along me on this particular event. I assisted in the setup as a matter of course, and he was quite generously dropping a bit of hints here and there. First he showed me how to measure chassis leakage current while swapping ac polarity. So I asked him - how could ordinary users check if they don't happen to make a multi-meter on hand?

 

As he explained that day - first remove all wiring connection to the equipment being checked. With the ac plug connected in one direction, feel the front panel of the metallic chassis with the back of 1 finger. Normally one can feel a small, but perceptible vibrational buzz on the back of the finger as the finger slide across the metallic surface. Next, reverse the ac polarity and test again. 1 orientation will produce less vibrational buzz compared to the other orientation. The one with the less vibration buzz is the correct ac polarity. This correspond to the same test using a multi-meter. The one orientation that yield less chassis leakage voltage readout is also the correct polarity.

 

But can one hear the difference? Yes!

Share this post


Link to post
Share on other sites

Levardin Amps have the hot pin marked in red. Apparently this is the "wrong" way round for Australian power cords.

I compared a Levardin with cords of different polarities (one matching their preferred way and one that was the australian standard way)

Zero difference. My wife and kids who have much better hearing could hear no difference (not even from the kitchen) 

Share this post


Link to post
Share on other sites
Posted (edited)
13 minutes ago, jeromelang said:

 

The second time when i encountered this issue, I had already changed my job, and was flying around the world making demonstration to distributors with a myriad of audio only and av products. The company's chief engineer had come along me on this particular event. I assisted in the setup as a matter of course, and he was quite generously dropping a bit of hints here and there. First he showed me how to measure chassis leakage current while swapping ac polarity. So I asked him - how could ordinary users check if they don't happen to make a multi-meter on hand?

 

As he explained that day - first remove all wiring connection to the equipment being checked. With the ac plug connected in one direction, feel the front panel of the metallic chassis with the back of 1 finger. Normally one can feel a small, but perceptible vibrational buzz on the back of the finger as the finger slide across the metallic surface. Next, reverse the ac polarity and test again. 1 orientation will produce less vibrational buzz compared to the other orientation. The one with the less vibration buzz is the correct ac polarity. This correspond to the same test using a multi-meter. The one orientation that yield less chassis leakage voltage readout is also the correct polarity.

 

But can one hear the difference? Yes!

 

Let me rephrase the question again.

 

But can one "see" the difference? 

 

There are those who can "see" and and there are those who cannot.

 

The trick is learning how to "see" into the music, rather than just "hearing" it.

 

In the course of my work, I've come across many people who can only "hear", and they have not been educated how to "see" into the music. That's what separate the grain from the chaff. Read the way they describe their sonic experiences, you can probably guess who those "hearers" are...

 

 

 

Edited by jeromelang

Share this post


Link to post
Share on other sites


1 hour ago, jeromelang said:

Changed the subject title.... 😁

And that seems quite disengenuous.

Share this post


Link to post
Share on other sites

 @jeromelang ... can I suggest that you should change the subject title again ... to avoid mis-directing people into thinking you are advocating unsafe electrical practices?

 

How about "Why does ac orientation affect sound quality "?

 

BTW - I use the 'AC meter method' when determining which end of the power transformer's primary winding should be connected to Active.  As you say, measuring for the lower AC reading on the chassis gives the 'right way round'.

 

Andy

 

Share this post


Link to post
Share on other sites

Back in Germany, many years ago, it was quite important, and I had all audio mains plugs and sockets marked with red dots next to the hot pin. That was of course because in Europe there is no fixed assignment of L and N pins, as mains plugs are reversible.

 

In Australia, there is no need to worry about this.

Share this post


Link to post
Share on other sites
Posted (edited)
22 minutes ago, Steffen said:

Back in Germany, many years ago, it was quite important, and I had all audio mains plugs and sockets marked with red dots next to the hot pin. That was of course because in Europe there is no fixed assignment of L and N pins, as mains plugs are reversible.

 

In Australia, there is no need to worry about this.

 

Correct, S - that is, from a safety PoV.

 

But, because you have no option in Oz to 'flip' mains plug orientation ... how do you know that your SQ is optimal?  (IOW, did the mfr orient the correct end of the power traffo's primary winding to 'Active'?)

 

Andy

 

Edited by andyr

Share this post


Link to post
Share on other sites


The idea back then was, it doesn’t matter which way the plugs are plugged in, as long as they’re all plugged in the same way around. I never looked into whether that made sense, or why. I just went with the flow :)

 

Share this post


Link to post
Share on other sites
2 hours ago, jeromelang said:

 

Let me rephrase the question again.

 

But can one "see" the difference? 

 

There are those who can "see" and and there are those who cannot.

 

The trick is learning how to "see" into the music, rather than just "hearing" it.

 

In the course of my work, I've come across many people who can only "hear", and they have not been educated how to "see" into the music. That's what separate the grain from the chaff. Read the way they describe their sonic experiences, you can probably guess who those "hearers" are...

 

I’m sure you’re pulling a left leg!

One of the safety taught when working on mains equipment is that you cannot see, hear or smell electricity.  So you must operate with the mains turned off, unless you’re a different species with a special sense......😀

 

2 hours ago, jeromelang said:

 

Share this post


Link to post
Share on other sites
2 minutes ago, Addicted to music said:

 

I’m sure you’re pulling a left leg!

One of the safety taught when working on mains equipment is that you cannot see, hear or smell electricity.  So you must operate with the mains turned off, unless you’re a different species with a special sense......😀

 

You must be one of those pathetic people who can only "hear" the music rather than "see" it.

(Hint, I am too… I feel so small and insignificant …)

Share this post


Link to post
Share on other sites
5 minutes ago, Steffen said:

The idea back then was, it doesn’t matter which way the plugs are plugged in, as long as they’re all plugged in the same way around. I never looked into whether that made sense, or why. I just went with the flow :)

 

It’s a safety issue that the active and neutral have a universal identification so consumers can operate the equipment safely and service personnel can service the equipment knowing which line can kill.

otherwise there is no difference....  All equipment operate with a DC supply, so to convert the mains to DC this is what’s needed where a transformer reduced the AC via windings to the correct acceptable level and like someone else has posted it will then go through what’s known as a full wave bridge rectifier to convert to DC.   So those who think they can detect a difference which side the active is connected to a transformer; please explain!

EE9471B5-1D52-4FA0-A7D6-18411C5532B6.png

Share this post


Link to post
Share on other sites
6 minutes ago, sir sanders zingmore said:

You must be one of those pathetic people who can only "hear" the music rather than "see" it.

(Hint, I am too… I feel so small and insignificant …)

It sucks to be a normal human being......  

Share this post


Link to post
Share on other sites

Why do people always like going around the same old circles time after time?  You have to be a true believer.   Nothing new to see here,  move along now...

Share this post


Link to post
Share on other sites
6 minutes ago, aussievintage said:

You have to be a true believer.

 

I thought the phrase was "true Belieber "?  :lol:

 

Andy

 

Share this post


Link to post
Share on other sites
23 minutes ago, andyr said:

 

I thought the phrase was "true Belieber "?  :lol:

 

Andy

 

 

I wondered what you were on about, then Justin time I figured it out...

Share this post


Link to post
Share on other sites
1 hour ago, aussievintage said:

I wondered what you were on about, then Justin time I figured it out...

 

:lol:

 

Andy

 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Classifieds Statistics


    Currently Active Ads

    Total Sales (Since 2018)

    Total Sales Value (Last 14 Days)

    Total Ads Value (Since March 2020)
  • Recently Browsing   0 members

    No registered users viewing this page.


×
×
  • Create New...