Summit: correct Mains Polarity

Hello,

i´ve tried to figure out the correct Mains Polarity for my Summits. Although I was able to to this for any of my other components by listening and verifying through measurements, I´ve failed this time.

There are slight differences when turning the IEC Plug 180 degrees. If you look at the backside mains connector (which is upside-down) the right pin sounds warm and voices have a very full timbre. But stage is not as defined as if the mains phase runs into the left pin.

Measurements (leak voltage to ground potential) fail, because the power supply obviously switches only with music signal.

What is your expierience and how did you connect mains? Are there any methods to figure that out by means of a voltmeter?

Br
Johann

Color me confused - how does this change the "polarity" of alternating current? By it's definition the polarity of AC alternates (in the US at 60Hz - or cycles/per/second)..

Is there some magic here that normal physics and quantum mechanics has missed?

Hi BN,

So you are talking about the power plug, without the ground pin, inserted into the AC outlet and reversing the insertion direction. Correct?

GG

In Europe this is more a problem than in the US, because here you can insert the plug into the wall two ways. The wall sockets have two ground pins at the edges of the inlet. And apart from the ground pins, there is one neutral 'hole' and one with the alternating current. If you do not know which of the two is the neutral, you might end up with the current flowing through your component the wrong way. This is not a real problem for most devices like coffee makers or vacuum cleaners. But it can affect the sound of audio gear. Usually, you can measure the correct polarity (= the correct way to plug the cord into the wall) by uncoupling the device and only connect it with an electrical cable without grounding into the 230V. With a Volt meter, you can see that there is some current on the neutral part of, by example, an rca outlet. If you then twist the power plug 180 degrees and do the measurement again, you will measure more or less current. The position of the plug with the least measured current is the best.
You can hear the difference aswell. The imaging of the sound changes when the polarity is changed. The problem bluenote56 is having, is that he cannot measure the current, because the Summits will not go on without music being driven into them. And it is impossible to do the measurements with the speakers connected to an amplifier, because the amp is probably connected to a grounding terminal.
Maybe there is a solution. That is to connect the Summits to a battery driven device like a ghettoblaster, making sure this is well isolated from the ground. In that case, the Summits will go on, and you can measure the correct polarity.
I hope this helps... I am am by no means an expert...

Hello,

I almost forgot about my post ;-)
Good to have some replies now. many thanks!

Yes, the situation is exactly as Nutshell has decribed. Here, in Europe, we are able to insert mains plugs in either two directions into the wall outlet. So, you have to figure out the right "hot" pin.

Very nice idea to fake music signal by some other device with no ground connection. I´ll try that out and let you know.

Br
Johann

I had always thought that Europe had more stringent electrical standards than North America, and that you could never have a power plug without a ground pin.

It's not main's current that's flowing the wrong way, after all this current reverses itself 100 or 120 times per second. What it is - is on most equipment, there is a small amount of leakage current from the unit's power supply AC primary to the chassis. While this current is very small indeed, it can create a large AC voltage on the chassis when measured to Protective Earth or Safety Ground. In some cases, reversing the two pin AC plug will reduce this voltage and (maybe) improve the system sound.

Bernard said:

I had always thought that Europe had more stringent electrical standards than North America, and that you could never have a power plug without a ground pin.

Click to expand...

Its not a plug without a ground pin. The european plug has a symmetrical design with 2 pins and 2 ground contacts. therefore you may insert it reversed. It will always match.

Speedskater said:

It's not main's current that's flowing the wrong way, after all this current reverses itself 100 or 120 times per second. What it is - is on most equipment, there is a small amount of leakage current from the unit's power supply AC primary to the chassis. While this current is very small indeed, it can create a large AC voltage on the chassis when measured to Protective Earth or Safety Ground. In some cases, reversing the two pin AC plug while reduce this voltage and (maybe) improve the system sound.

Click to expand...

Indeed, I've read that one of the signs is greater EMI from the unit if "wrongly" polarised.

If measuring the AC by means of a voltmeter is difficult like with the Summits, I see only two possible alternatives:

- Presume that ML has observed the international wiring standard, which means that the Live shall enter into your speakers through the left-side pin of the IEC plug installed on the back of your Summits. Since the plug is upside-down on these speakers, it is the right-side pin in this particular case. If the manufacturer has observed this rule (that is quite certain) you will just have to ensure (by means of a simple voltage tester) that after you've plugged your power cable to the mains, the Live “appears” in the right-side hole of the IEC socket at the end of your power cable. If not, just reverse the Schuko plug at the other end. This picture is much more talkative:


- Trust your ears. If reversing the polarity has no or little effect on sound and the choice is not evident, just forget all of this polarity thing You will in no way harm your Summits by plugging them reversely.

Domchuck said:

Trust your ears. If reversing the polarity has no or little effect on sound and the choice is not evident, just forget all of this polarity thing You will in no way harm your Summits by plugging them reversely.

Click to expand...

That´s excatly what I do in addition to measure the leakage current. I only measure to verify what i´ve found out by listening. Obviously most manufacturers observe the correct internal wiring, means: "live" at the right side hole. Only a few exceptions: the Benchmark DAC-1 USB is reversed as well as my Paravicini E.A.R. 864 preamp. As measuring does not work with my Summits and i think the standard polarity works best, i´ll stay with that.

Many thanks for your input!

Johann

In any and all modern electrical units and equipment, both the Hot and Neutral wires are well insulated from the chassis. In most equipment the chassis is directly connected to the Safety Ground/Protective Earth (EGC/PE). Other units have passed special safety tests and do not require this connect to their case.

The voltage on the chassis under discussion is caused by capacitive leakage in the unit's power supply, it has almost no available current and is not a safety concern. But this voltage can be sensed by the audio inputs in some equipment and it's possible that it effects the sound.

bluenote56 said:

As measuring does not work with my Summits and i think the standard polarity works best, i´ll stay with that.

Click to expand...

I shall admit that I haven't tried to hear the effect with reversed polarity, I instantly plugged the Summits the regular way, I'm pleased to hear from you that I will probably not need to make a try

PS: I also made measurements with a cheap voltmeter some time ago, my amp showed the same amount of leakage current (almost none) no matter how it was plugged, I think my VCR was wired reversely, but all my other measurable components liked the regular plugging.

bluenote56 said:

Hello,

i´ve tried to figure out the correct Mains Polarity for my Summits. Although I was able to to this for any of my other components by listening and verifying through measurements, I´ve failed this time.

There are slight differences when turning the IEC Plug 180 degrees. If you look at the backside mains connector (which is upside-down) the right pin sounds warm and voices have a very full timbre. But stage is not as defined as if the mains phase runs into the left pin.
Measurements (leak voltage to ground potential) fail, because the power supply obviously switches only with music signal.

What is your expierience and how did you connect mains? Are there any methods to figure that out by means of a voltmeter?

Br
Johann

Click to expand...

Hello Johann,
Hello everyone else,

Please allow me one question to the above statement marked bold:
Did you hear the difference immediately after turning the phase or did you have to wait for a while to hear the difference?

Well you need to find a musical situation where it's audible. There is absolutely no burn-in in AC power circuits.

Speedskater said:

Well you need to find a musical situation where it's audible. There is absolutely no burn-in in AC power circuits.

Click to expand...

Well that much I knew I was just wondering whether turning the polarity will be audioble right after turning the plug?
The reason for my thought is that if you switch of the mains the speaker will keep on playing for quite a while without power and I would think that turning the polarity would need some time to be audioble.
That was the reason for me asking if turning the polarity will be audioble right away or if it would possible take some time.

The AC power polarity swap is about background noise/interference/leakage levels. All are in the 50/60Hz to maybe 500/600Hz range and none of which are stored.