Polarity of PowerPlants

Sorry for the question if obvious. How can I check polarity of the schuko outlets of my P12 EU version? Which is the phase exactly? As usual @jamesh can you help me?
I would be sure that the phase is the same in each outlet, I assume it’s on the right hole facing the outlet (looking at the rear panel) where I see the ‘+’ symbol on it

While for the IEC inlet of the P12 (and in general PSA gear as BHK Preamp / DS DAC / PST / stellar M1200s / Stellar Phono) is always the phase the pin on the left side as shown (NO.1) in the picture here attached? Here again where I see the “+” symbol…

The aim is to correctly connect each PC (AQ Dragon in my case) from wall to P12 and of course from P12 to amps and sources, in order to plug all with the phase in the correct position

Wich phase tester do you recommend both for schuko socket and IEC inlet?

Thank you.

The back panel of the P12 is correct. If you follow that, you should be all set.

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Thank you James.

I’m curious: all the other PS Audio components above mentioned (BHK Preamp, DS DAC, PST, Stellar M1200, Stellar Phono and so on) I assume that they follow the same rule, referring to the IEC inlet phase pin position, is it correct? I’m asking because I do not see any symbol on their back panels. Is there a factory standard design?

Last question: I’m looking for a phase checking device able to determine the polarity of cables, I tried a few contactless pens (cheap models from amazon) with led display but they gave me bad results, not really precise.
When the cable is plugged to wall socket (or to P12 outlets) I would test the correct phase position on the IEC plug connector on the other side: what device do you use?
For example I find on the web this device, unfortunately it is out of production since a few years:

I read an interesting paper from Garth Powell (AudioQuest) titled “Power Demystified” (I’m sure Al would appreciate) in wich at page no.29 the author suggests to always check by ears cables polarity

I find quite odd from a cable manufacturer this assumption. Not only because I’m a lazy man. Why do not put a lable/symbol to indicate the polarity on their cables connectors, both on the schuko and IEC plugs? Does it mean that it would be cable dependent and each cable of the same model/brand (Dragon HC or Source for example) may vary the phase wire position?

You US guys are fortunate not challenging with this issue but EU folks must fight against this lack of standards and it seems that AC polarity in hifi systems is not considered a subtle matter in audiophile community.

Any suggestions/experiences?

Thank you.

In my experience, wattgate does identify the phase with a star on the side of the plug (at least on their higher end line). So does Furutech. But I always check with a multimeter. It is easy to find phase. Just measure each inlet against ground (right and left ones against the middle one). Neutral should be 0v or very close. Phase should be whatever voltage your power company delivers to you home.

I would use something like this (both of them):


You can’t use a Schuko one because it allows reversing. You’ll need to use something like BS 1363 per the above, NEMA, or AU/NZ where it only allows a single direction for the plug to be plugged in.

So with that, I would test the polarity of the cable plugged into the wall:

Wall → Schuko → cable → IEC C13 … then into adapter IEC C14 to BS 1363 → polarity tester

This should ensure correct polarity between wall and PS12 or power distributor. Then plug the cable from wall into PS12 or other power distributor. Then test again the cables from the PS12 or other power distributor using the same method to ensure correct polarity between PS12 or power distributor to component.

Let me know if that doesn’t make sense and I’ll take some pics and post.

EDIT: I should also mention that power distributors and conditioners designed for EU/Schuko usually design around plugins being able to be swapped around (or plugged in reversed (?!?) if reverse is even the correct word). E.g. Shunyata power distributors have two filters attached, one to active, and one to neutral for EU/Schuko devices whereas for non-EU/Schuko, they only have one filter attached to active.

Thank you so much. James already confirmed me that as shown on the picture I previously posted, on the back panel of the P12 (EU version) a few symbols indicate the correct polarity both for schuko outlets and IEC inlet. So feeding the rest of the components according to this polarity symbols all the system is inherently correctly plugged.

As for the first meter from wall to P12s I just ordered this IEC ADR tester NO.1:
As soon as I receive it I’ll tell you if it works.

While I already use to check polarity wall sockets this one:

It does the job.

And at the end I’m giving a try to test polarity from components IEC inlets to this device:

frankly not very satisfied due to controversial results, even if correctly grounded. It seems to find the phase both on right and reversed on left. Mah!

The problem is, we’re assuming cables are properly wired with earth at the top, which I’ve found isn’t always the case :wink:

Testing polarity on the IEC C13 end seems like the best bet to me.

Totally agree. I found two old AQ Dragon HC cords with reverse side polarity compared to the rest of same cords (more recently purchased in effect). I sent an email to AQ asking if they have a standard factory rule for polarity design, they forwarded the email to a department manager in The Netherland and I’m still waiting his answer.

Hi @luca.pelliccioli
Are all termiated with Schuko plugs? If yes, does that mean the Neutral and Earth were mixed?

That would be bad, more likely active and neutral reversed so Earth hole could be at the top or at the bottom.

Ignore the coloured lines below
Left to right - Active, Earth (top), Neutral

Or reversed:

Left to right - Active, Earth (bottom), Neutral

Both will work with most parts of EU with Schuko outputs, not in some parts of Euro where there’s a little pin in the socket for Earth.

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But can’t live an neutral be inverted by turning the cable with a Euro plug 180 degrees at the mains / regenerator socket? Something that cannot be done with pluges designed for US, UK, AU …

Yes all Schuko cable, Dragon HC and Source and Tornado HC for subs. The 2 old Dragons need to be plugged inverted right/left into the wall socket to have the phase on the IEC connector at the correct point (right side if earth up - on 3.00 clock hour position). Look at no.1 here.

All the other (recently purchased) Dragons/Tornados have the phase in the same IEC connector place no.1 only if they are plugged into wall socket differently, left/right as shown here below:

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I get it! Things have to be done properly if one is using this socket:

Rather than this socket

Yes, exactly! That’s why IMO, it’s best to test polarity at the IEC C13 end of the cables before plugging it into components (and power distributor inlets).

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All clear to me now! Yes, they should make them ready for everybody, and make sure the whole stack is fully aligned!

I agree, my P12 sockets and wall receptacles are designed in the same way

Oh, there is such a thing:

From Leaderman Earth Continuity and Polarity Test Kit With IEC Extension Lead ECP-K4 | eBay

It would be useful if famous and trusted brands of gears and cable always clarify with symbols where is the phase in their EU models.

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Yes indeed, this is the reason why I’m checking all my cables to be sure.

Polarity of wall sockets, done. (Also with my electrician because it is a dedicated line).

Polarity of powerplants outlets, done. The symbols on back panel are very clear and James confirmed too. Thank you so much PS guys, please do the same on other components for IEC inlets.

Polarity of AQ cables, done. Each one. Awaiting in any case an answer from factory reps.

Quite time consuming and accessories needed, all would be avoided with a little bit of help from designers. But that’s the hobby we all love, you know…