Does electrical polarity really matter?

I just bought an Oehlbach Powersocket 907, which is supposed to protect my system by providing a stable power supply. It has filtered and unfiltered plugs, unfiltered being for analog and filtered for digital.

It also has a polarity control for the main lead, a light that only goes on if the polarity is correct. It only does that for the main that goes into the wall: if you want to ensure that every device attached to the socket has the right polarity you need another device called Oehlbach Phaser (another 60 euros) which I haven't yet both.

The manual stresses the importance of every device being connect with the right polarity into the electrical socket, to "get the proper sound out of your system".

This introduces a new (and unknown for me) level of complication in the long a winding road to achieve good sound.

I just wonder: are these guys just trying to get some extra money out of me, or does electrical polarity really matters and make a difference? Also, does a DAC and a network player belong to the digital or analog domain, where do I plug them?

 

Ah...theoretically if the components aren't all grounded the same you could have currents running in the ground planes which could muck stuff up. I don't think that should be an issue unless a designer made a weird choice? And anyway, aren't your Euro plugs asymmetric? Or is that just in the US? Here most equipment comes with 3 prongs, and one is wider, and you cannot normally or easily change the polarity of the plug anyway. Except, small "wall wart" supplies like low-power DACs and small amps have can be reversed...very interesting question you raise, I hope some designers chime in.

 

The plug here have 2 prongs, looking exactly the same, at least to me. I'm really unaware of any electrical matter, completely ignorant about it so I have no idea what asymmetric pluc means..

 

Never encountered the inside of a EU plug but after viewing this video, getting consistent wiring seems fairly straightforward.

 

If the polarity matters for the component, in the U.S. at least, one prong of a two-prong cord will be larger, and thus prevent incorrect polarity.

There are rare situations where the mains power was wired incorrectly at some point upstream of the wall outlet, that is why some components come with polarity switches. This is most often a feature found in analog preamps.

I imagine that in many European countries, with their strict regs, if the polarity is important, the plug will be three-prong and thus prevent an improper connection.

There are some components that do invert polarity for whatever reason. This can result in reverse polarity at your amplifier output taps, which can be corrected by simply swapping the +/- speaker cable leads at either the amp or speaker end.

 

It matters for safety. Digital.
-Bill

 

I guarantee half the homes in America have hot wires connected to the larger prong opening in their electrical outlets and the neutral to the smaller size. That is the reverse of what it should be. But home many homes are actually constructed with an licensed master electrician doing their wiring???
It's AC though... for many applications, it doesn't much matter. With the advent of AFCI breakers and more electrically sensitive devices, it probably is becoming more important than it used to be

 

Thank you. Does filtered versus unfiltered also affect sound in any way?

 

Thank you.

 

Mains polarity matters (ie which is live and which is neutral) because of the power transformer in your audio gear. If it is a toroid, or an EI with primary and secondary overwound, you need the neutral next to the secondary. The neutral is close to ground voltage. If the live is next to the secondary you have 110V or 240V ac right next to the secondary, and capacitively couples to the secondary. Not just 60 or 50Hz, but all the harmonics of the distorted mains power waveform, and all the spikes and RF crap too.

Provided the transformer has been wound properly (ie with the right grade of wire insulation, and an insulation barrier between primary and secondary, and creepage and clearance are adequate), it does not make any difference regarding electrical safety, but it does have sonic consequences to get it the right way round.

 

Woah....full stop. Let's squash this one right now. AC power polarity has nothing at all to do with audio polarity. Not at all related.

With unbalanced power, as we have in the US, some transformer leakage can result in extra noise that flipping the polarity can change. In those rare cases, re-wiring internally is the correct solution. Detection is via floating the device, and measuring voltage between the chassis and ground. Then via a grounding adapter, flipping and comparing the result.

Changing AC polarity via a grounding adapter is not right, long term, as you want fuses and power switches in the hot leg. I would wonder in the OP's case what they're doing about that safety issue.

CJ

 

It can if there is something to filter.
-Bill

 

yes it does if you look at a schematic of a power transformer..

 

Guarantee, huh? How do I claim the reward of this guarantee?

The unions and regulatory capture pretty much make electricity a racket. An assistant can take the outlets out of the package but can't operate a screwdriver. An electrical engineer can design the power grid or a super-collider (or dishwasher) but can't put in his own dishwasher (if he plans to sell the home). They've even managed to weasel their trade into low voltage. I've had to sit on the phone for hours because the code-following inspection monkey wanted changes that endangered both signal and safety. The result is that yes, newly-constructed homes have a licensed electrician connect the white wire to the silver wire terminal.

 

Newly constructed homes may have electrical contractors that operate under the licences of a master licensed electrician. Doesn't mean that their homes were wired by the licences holder. Also, low voltage work usually doesnt require a license though union heavy cities would make it a point to claim that work for their local.
But none of that was my point. My point was that most people wouldnt notice if the polarity of their receptacle was reversed because most things powered by AC will work regardless of whether or not the hot and neutral are reversed.

 

Well, looks like NY is a bunch of boilermakers and burglar alarm companies that will work over your kneecaps if you don't go through them if your secretary can see a DVR screen. But indeed, NY state legislation for alarms surreptitiously sucking in networking:

NYS Division of Licensing Services

If you want to be an electrician, a shortcut is to supplement your MSEE with 2.5 years of washing the company truck and loading spools.

 

Your answer is very interesting. Can you be more specific, i.e.: what do you mean by "something to filter"?

 

Would you use non filtered sockets? I'm not sure yet, as I try to leave room to the fact that I could biased, but it seems to me that filtered sockets are deteriorating sound, take some life out of it...

 

All audio devices are filtered through their power supplies. It is therefore unnecessary to filter the AC line. If there is by chance any RF higher frequency in the AC line, it will be completely filtered out by the power supply. It is beneficial however to have AC voltage surge protection and lightning suppression.

The AC line polarity is important. Correct polarity lowers any potential ground loop differentials, and hum problems. I have never noticed any audible difference from reversed polarity (although it may exist) but have encountered hum issues. This was first observed in my early life working in a band. We always made sure the ground switches on our amps were correct, otherwise we could get zapped pretty good! So, a reversed AC plug can be a safety issue. The safety concern is where a device "sees" AC voltage to chassis, mostly older gear up to about 1970. (here in the USA) Some vintage devices have floating ground reference, which is lifted from chassis ground... a safer design.

If any device has the old non-polarized two prong plug, you can always determine correct polarity by touching the tip of an open RCA plug. Have the volume set lower to prevent a loud "buzz", flip the plug in the AC outlet for the lowest level hum, you're done. (don't do this on wet grass, ok? you're safe in your house on a wooden floor.. lack of common sense kills) I have never read about anyone shocked or killed by a correctly polarized guitar amp or hifi device. Of course, a three prong grounded AC connection is safest. The problem exists when one device is not ground referenced correctly.. or plugged in "backward".

Of course, the three prong grounded connection has made things "idiot-proof" much to the disadvantage of human-kind, since we have one less method that undesirables can remove themselves from the gene pool. (sarcasm)

 

Thank you! This is very clear. Just one thing: say I want to chech the correct polarity of my DAC. What RCA plug do I need to touch, the female one on the DAC or do I disconnect the RCA that goes into the amp an touch that? Sorry, this is the last bit of confusion I have... could you clarify a bit more?

 

That's a good question. I apologize for being unclear about country and line voltage. Your country is 230v 50 cycles, so the AC plugs should have a ground pin, and be proper polarity, and only insert one way. Your AC conditioner verifies proper polarity at the wall outlet, so you're good to go.. every device plugged into it will be correct polarity.

There is a way to check the DAC for mains polarity, but of no point to outline, since they plug in one way.

One thing to be aware, especially here in the USA and all other countries on 100 to 120v single phase... all audio equipment should be plugged in the same wall outlet. (or on the same leg from the electrical panel) This is good practice anywhere in the world, since one wall outlet can have more voltage drop than another when under load. (*just plug in the same outlet, then no worries.. exception would be high current mono blocks drawing 10 amps each.. we would need to have them on a separate outlet) In all other circumstances, we want all audio gear on the same outlet. On the other hand, avoid two different legs from the electrical panel operating the same system. The opposite phase of each leg will cause hum problems, and can be a safety issue.... which is never mentioned in any handbook I've ever read. However 230v line voltage is always the same phase throughout the home, (given the outlets are wired correctly) so no worries about that in your country.

 

Thanks, but what about the "touch the RCA" you were referring to earlier on. How does that exactly work?