AC Polarity and You

[pmkap]

.....
While on the subject of polarity, it's a good idea to test all of the outlets in your house for correct polarity and working safety ground. Especially if your house was built during the housing bubble when "less experienced" workers probably did the wiring and inspector was too busy to check every outlet. Could be the polarity is wrong at the wall, or ground has come loose with changing seasons.

Indeed.... and given that there is a vendor out there of audiophile power conditioners that is either totally ignorant of, or uncaring about standard safety practice, that they put a 5+ uf cap from neutral to ground as a 'unique' approach to power conditioning. With a not all too unusual double fault wiring (reversed hot & neutral and a floating ground, it will put a lethal, above let go current on all connected grounded chassis.

I really wish I was making this stuff up...

FWIW,
Paul

[melgross]

It's not dangerous if you understand what you're doing and have a good reason. Audio is a fine art, not limited by National Electrical Code.  Rollo is just recommending the buster as a tool to look for design flaws. Product engineers are not always as insightful as audiophiles.

You don't want to leave your equipment powered through a ground buster though. You would lose the safety ground which activates the circuit breaker with or without neutral.

I understand what I'm doing, and that's WHY I don't recommend it. The assumption for audiophiles that they exist outside the laws of physics and common sense, is amazing to me. Manufacturers ground, and polarize their equipment for very good reasons.

What would be the point of this exercise if not to eliminate the ground and polarization if it's thought that doing so would result in some "improvement"? It's best not to even bother looking. And you could have a problem from just playing with it. You never know.

First of all, fuses and breakers in a unit are almost always on the hot side of the power supply, so that if they break, the equipment will be rendered safe to touch. Otherwise, the entire chassis, often including metal knobs, faceplates, covers, etc. can be hot, and touching that while touching a grounded piece will send the current through your body. Nasty stuff! Refrigerators are grounded for good reasons. It used to be that if a problem occured, and someone was touching the fridge and touched a grounded part of a sink, e.g., any metal part, they would get electrocuted.

Removing a ground from equipment that's designed with one also eliminates the safety. In that case, chassis ground and circuit ground are two separate things.

Some manufacturers, such as my Bryston, have a ground lift switch in the back, but, they design the equipment to be safe either way, though the ground does add an extra level of safety to the product.

Even if you don't worry about the danger to health, you should know that in the case of a line surge, the equipment may no longer be protected.

There are safer ways of doing this, though they are more trouble, and may cost some money.

[melgross]

I'm confused then. When a two prong plug comes with a component and the correct orientation is NOT marked how is it grounded ? The other puzzling thing is some manfs recco lifting of the ground, PS Audio CAT, Lector. Why would they impose a liability on themselves if it was so dangerous. Mel, Tom ?
   I am curious not defending any position.


charles

Quite a while ago, plugs weren't polarized. But way back in the 1060's it was understood how dangerous that was. not just equipment melting down. Nt only people being electrocuted, but houses burning down. That's why plugs have been polarized since then.

Three wire grounding is even better for many equipment designs. It isolates the electrical circuits from the chassis.

IF a manufacturer allows the lifting of the ground, then, as I said, the equipment was designed to b safe that way as well.

But think about it. Why would their preferred method be three wire grounding in the first place?

Also, there is equipment that doesn't have polarized plugs. but that's stuff that doesn't need it. If it has it. It needs it.

[Carlman]

Thanks for sharing this tip, Rollo.. If I get so inclined, I'll go check it out.  It's tough to get into my cabinet to test things so it'll probably go untested for a long time, though.  

As to the safety concerns, THANKS if you're genuinely interested in helping your fellow audiophile from... some general sort of risk... but...

I'd much rather see people ask questions and get more details about the experiment first, then offer suggestions on how to make it even better or safer based on their own experiences, not anecdotal, broad and generalized observations... with no suggestions and a wagging finger instead.

We're grown adults here and no one is putting a (soldering ) gun to your head and forcing you to do anything.  Working at your own risk is assumed.  The pedantic diatribe is unnecessary.

-C

[melgross]

There is no need to fear electricity if you understand it and take precautions. If you don't understand it, don't mess with it, but you will miss out on Charlie's discovery.  If you understand the danger then you are able to explore safely, and that is fun.

Leaving the ground buster in the circuit for normal operation is unsafe no matter which polarity sounds better. But if you swap the hot and neutral at the transformer or in the power cord as Charlie suggests and maintain safety ground, it's not dangerous to swap hot and neutral. It is illegal to do it in the wall outlet.   

SAS preamps have a polarity switch on the back for this purpose. Sometimes the difference is audible. It was not audible on my dedicated line. But on a shared line where neutral has more wire nuts or a bad connection somewhere raising it's impedance, it might benefit to swap the polarity. I don't understand how it could improve the sound, but rollo is offering a possible reason, which intrigues me to try his test. 

Some audiophiles lift the ground on their amps and source to allow the preamp to be the ground reference for the whole system. The technique might lower noise. But then safety depends on whether chassis ground is connected to signal ground - by design it may not be, and how much you trust the ground wire in your interconnects and all those solderjoints, nuts and bolt star grounds, cheap RCA connectors. I insist on safety ground on every component, unless it is double insulated like my Sansui tuner. It has equal width plug blades which was the norm for all appliances in '79 when many houses still did not have 3 prong outlets. I know it was tested safe and certified for legal importation from Japan.

While on the subject of polarity, it's a good idea to test all of the outlets in your house for correct polarity and working safety ground. Especially if your house was built during the housing bubble when "less experienced" workers probably did the wiring and inspector was too busy to check every outlet. Could be the polarity is wrong at the wall, or ground has come loose with changing seasons.

Changing the wiring to the power transformer is not solving the problem. It's exactly the same as reversing the polarity of the plug. Why would you think that it's safe that way?

I also must agree with one thing you've said, as it's a very important point, and is often overlooked. More often than imagined, the sockets are reverse wired. It wasn't just during the housing boom. That's a screw-up that occurred ever since polarized plugs first came into being. Older electricians would often forget that they were working on polarized outlets, and simply connected everything up the way they always did. Even experienced electricians make these mistakes, and that's why they are supposed to check the outlets, one by one. but they often don't. I have some professional equipment for that purpose (the cheap $7 polarity testers don't always work properly), and found over a dozen outlets in my house when we first bought it, that were backwards! So the first thing is to test the outlet with a voltmeter. it's simple enough. The small slot is hot, and the wide one is neutral. 122 to 124 volts between hot and neutral is normal these days. 122 to 124 to the ground screw from hot is normal. Neutral to screw should be no more than about 2 volts. lower is better. For those who have Romex, the screw may not be grounded, and you likely have a plastic box. Terrible stuff! Hot to ground should be the same as hot to neutral.

Find something that's grounded. A radiator may NOT be grounded!!! This is important. If you go hot to radiator with a two wire outlet, and get nothing, that doesn't mean anything. If you have three wire outlets, no more than about 2 volts to ground from neutral is acceptable. The lower the better. Neutral is only connected to ground at the main box. At least, that's the way it's supposed to work.

I would never trust ground wires in interconnects, as they are not designed for that purpose. Even worse are the interconnects that do odd things with the ground circuit.

[melgross]

Thanks for sharing this tip, Rollo.. If I get so inclined, I'll go check it out.  It's tough to get into my cabinet to test things so it'll probably go untested for a long time, though.  

As to the safety concerns, THANKS if you're genuinely interested in helping your fellow audiophile from... some general sort of risk... but...

I'd much rather see people ask questions and get more details about the experiment first, then offer suggestions on how to make it even better or safer based on their own experiences, not anecdotal, broad and generalized observations... with no suggestions and a wagging finger instead.

We're grown adults here and no one is putting a (soldering ) gun to your head and forcing you to do anything.  Working at your own risk is assumed.  The pedantic diatribe is unnecessary.

-C

Well, Tom is a power engineer, and he knows what he's talking about. I had several years of electronics courses in college as well as four years of physics, and then several years designing professional and commercial audio gear, as well as digital equipment for several clients.

What we're saying is fact. If someone wants to disregard it, it's up to them. If you think the electrical code is wrong, you should try to have it revised, but I can assure you that it is not.

For many years now, audiophiles have been saying to lift grounds and reverse polarized plugs. It's nothing new. It's just as dangerous now as it was then.

There is no way to make an experiment that is inherently unsafe, safe. If the result is that the unsafe condition is maintained, then that's how it will end up.

Why is it that when someone isn't happy about what others say, they call it a pedantic diatribe?

Just as we don't have to do this, others don't have to listen to what we say.

And Rollo did ask us to explain further.

[Carlman]

Oops.. I missed that Rollo asked for it.  My apologies...  However, you make a lot of assumptions about how I feel which aren't the case and it's another sign of what I'm talking about..

I was neither happy or unhappy with what you said. I have no emotional iron in this fire.  Right now, this is one of those posts where one guy does a cool experiment.. and then people condemn and say how he's wrong... even though he had positive results and is alive to tell about it.  That's the problem, and that's not what AN is about.. nor will it be.  

BTW.. the post below is a great example of a pedantic diatribe... I don't know how this post was written because you had to be standing akimbo when it was being typed.

I understand what I'm doing, and that's WHY I don't recommend it. The assumption for audiophiles that they exist outside the laws of physics and common sense, is amazing to me. Manufacturers ground, and polarize their equipment for very good reasons.

What would be the point of this exercise if not to eliminate the ground and polarization if it's thought that doing so would result in some "improvement"? It's best not to even bother looking. And you could have a problem from just playing with it. You never know.

First of all, fuses and breakers in a unit are almost always on the hot side of the power supply, so that if they break, the equipment will be rendered safe to touch. Otherwise, the entire chassis, often including metal knobs, faceplates, covers, etc. can be hot, and touching that while touching a grounded piece will send the current through your body. Nasty stuff! Refrigerators are grounded for good reasons. It used to be that if a problem occured, and someone was touching the fridge and touched a grounded part of a sink, e.g., any metal part, they would get electrocuted.

Removing a ground from equipment that's designed with one also eliminates the safety. In that case, chassis ground and circuit ground are two separate things.

Some manufacturers, such as my Bryston, have a ground lift switch in the back, but, they design the equipment to be safe either way, though the ground does add an extra level of safety to the product.

Even if you don't worry about the danger to health, you should know that in the case of a line surge, the equipment may no longer be protected.

There are safer ways of doing this, though they are more trouble, and may cost some money.

About that last line...  since there are safer ways of doing this experiment, why do you now say this experiment can't be made safe?  I was wondering why you wouldn't divulge the safer methods you knew about.. It makes it sound like everyone here is too cheap or lazy not to try... That post sounded so disrespectful I had to say something.

I'll split this topic into another new thread about AC polarity so that can be discussed ad nauseum.  I do not wish to change electrical code but I do wish to change posting to AN to be more constructive.

[pmkap]

Mel,

Welcome to AudioNervosa. You said -

For many years now, audiophiles have been saying to lift grounds and reverse polarized plugs. It's nothing new. It's just as dangerous now as it was then.

That's quite a broad brush you wield. Like mime tossing, one never advocates the lifting of safety grounds as a normal operation. Maybe it comes with age, but I'm not quite the social Darwinist I once was.

http://www.audionervosa.com/index.php?topic=2070.msg21523#msg21523

A little background on what Rollo is getting at -
http://www.boundforsound.com/tweak.htm
http://www.audioasylum.com/audio/tweaks/messages/3/36909.html

As noted in the above references, the use of a cheater plug is for diagnostics only, not as a permanent fix for ground loop hum/noise. The object of the above is to minimize reactive leakage coupled to the chassis/safety ground. Safety grounds stay. By minimizing that capacitive/inductive coupling to safety ground, one attempts to minimize current noise on the safety ground(s). Balanced (technical) power is a more purposeful and effective way of doing this. As long as the fix is to reverse (or not) the polarity of the power transformers primary, after going through the proper extant fusing and switching, there is no harm, no foul.
The dreaded ground loop hum is largely a result of the lack of any standards in connecting single ended signals between our kit, and the multiplicity of connections from safety to signal ground. See-
http://www.audiocircle.com/index.php?topic=19860.msg177365;topicseen#msg177365

FWIW,
Paul

Some manufacturers, such as my Bryston, have a ground lift switch in the back, but, they design the equipment to be safe either way, though the ground does add an extra level of safety to the product.

If you examine their schematics you'll find that they never lift the mains safety/chassis grounds. Standing off the signal ground from the mains safety ground via a resistor or anti parallel diodes (with or wo capacitive hf bypass) or disconnecting the two does not effect safety.

Regards,
Paul

[tmazz]

I'll split this topic into another new thread about AC polarity so that can be discussed ad nauseum.  I do not wish to change electrical code but I do wish to change posting to AN to be more constructive.

Carl,
I want to, respectfully, disagree with your last statement. While you may not like the tone that it was written in, the post and the message that it conveyed was very constructive. The message was simple, regardless of the sonic result, messing with the AC polarity can cause dangerous and potentially lethal situations. Commercial AC power  is an extremely dangerous thing that we have come to take for granted as safe only because of the electric codes and safety systems that are regularly designed into every electric appliance that we use. And it is this same false sense of security that leads people to lift grounds and flip polarities without realizing what a dangerous action this actually is.  And I don't be live anyone who truly understood the downside risk of this type of action would ever consider doing it.

I watched a guy one time grab a TV set that he was repairing only to find that it had a short to the chassis (this was an old set that did not have a polorized plug and the plug was in backwards). As the electricity went trough his hands and arms it cause his muscles to tense up such that he could not let go. Luckily he had the presence of mind to step back from the bench and drag the set with him. The weight of the set ripped it out of his hands and sent it crashing to the floor. Although the set was wrecked, the tech lived to tell the story. And while the ODs of something like this happening to the piece of gear to lifted the ground from, if it does happen you may not be lucky enough to get a second chance. I don't think any audio improvement, no matter how big , is worth risking, damaging the equipment, burning down your house of killing yourself ( or someone else). But then again you would never catch me on a motorcycle without a helmet, even in a stage that doesn't have a helmet law.

The bottom line is that telling someone that they shouldn't something because it could get them killed is very constructive criticism indeed

[Carlman]

I didn't say the entire post wasn't constructive..  I thought his comments were destructive to the original topic.  That was (part of) my point.... I only want things to be 'more' constructive.  Here is a new thread to discuss the issue... that is more constructive.

[tmazz]

.... I only want things to be 'more' constructive.  Here is a new thread to discuss the issue... that is more constructive.