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Ok so I use vintage equipment and the power cord plug does not discriminate you can plug it in anyway you wish, being self taught I learned long time ago polarity matters a lot as how something can sound, less noise etc.
the old supposed correct way to find "correct" polarity would be to plug the unit in and measure the chassis voltage with ac meter to ground, the supposed correct polarity would be the one that has the LEAST amount of ac on the chassis and then ground the chassis. What I am finding is the exact opposite my stuff sounds better the other way.
I wonder what you guys have found?
Lawrence
Follow Ups:
In both cases I mis-wired the primary leads on the toroidal transformer. I found out (here on DIY) that the capacitance between the primary and secondary windings are different for each leg of the primary. The leads were correctly marked colored black and white. What a dunce!
The difference was in the noise level. I looked into it because there was a low hum in the output. Now, I never notice a hum, so I'm happy!
Can you open the case and look at where the wires from the cord are connected? If they're both connected to the primary of the power transformer and neither is connected to the metal chassis, then it doesn't matter (although you might consider a 3-wire set up the the 3rd ground wire connected to the chassis. However, if you see that one of the two wires is connected the chassis, then that should be connected to neutral at the wall plug.
Electraglide Power Cords didn't connect the ground because they thought it sounded better. I use all electraglide cords and think they sound terrific. One of their old cords did connect the ground, but the later cords sounded much better, but there were more changes than just lifting the ground. They sell reasonably cheaply second hand.
Plug the power cord in anyway you prefer. Otherwise, look for markings on one of the wires of the zip cord that either involve information about the cord, or a ribbed surface of the neutral wire. The wider prong socket of an AC outlet is the neutral polarity. Unless you are concerned about keeping the vintage power cord unmodified, you might consider re-terminating the zip cord with a HQ 3-pole AC plug, implementing the un-used ground prong as a polarity determinant only. Make sure to tighten the un-used ground prong termination screw so it does not rattle inside the AC plug.
Duster, cannot use thick 3 wire cords for my audio gear, but if you would be so kind to recommend, a nice 2 wire like zip that would be an honest improvement?
I assume you simply wish to replace a vintage 18 AWG captive power cord with something better. Rather than another zip cord type power cord, I suggest a 16/2 twisted pair power cord for lowered inductance and increased noise rejection, and while not substantial in audiophile terms, a 16 AWG conductor provides two-thirds greater cross section than an 18 AWG conductor.
Here's two power cord suggestions to consider: a low-cost option and a moderate-cost option.
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Home Depot carries a Husky 16/2 extension cord with a polarized AC plug that features very high-quality bare brass prongs. The power cord can be cut to the length desired, and hardwired to the component. Other 16/2 power cord products at Home Depot feature nickel plated AC plug prongs that should be avoided. It is only available as 12 foot length:
http://www.homedepot.com/p/Husky-12-ft-16-2-Extension-Cord-AW62611/100661438
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chuya-online in Japan sells a discount-priced Oyaide NEO 16/2 detachable C7 power cord with a gold plated non-polarized AC plug at one end, and a C7 connector at the other. A C7 inlet can be installed at the back of the component, or the power cord can be cut to length and hardwired to the component. Three lengths are available:
https://global.rakuten.com/en/store/chuya-online/item/53377/
https://global.rakuten.com/en/store/chuya-online/item/53379/
https://global.rakuten.com/en/store/chuya-online/item/53380/
Thanks, but will need more conventional zip cord style without any twisting, just looking for a slight upgrade, maybe DIY
Replacing vintage 18 AWG zip cord with new 16 AWG zip cord terminated with a bare brass 2-prong AC plug should still be a worthwhile thing to do.
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Southwire (By-the-Foot) 16-2 Black Stranded Lamp Wire:
http://www.homedepot.com/p/Southwire-By-the-Foot-16-2-Black-Standed-Lamp-Wire-55681899/204725033
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Leviton 15 Amp 125-Volt Light Duty Plug, Black:
http://www.homedepot.com/p/Leviton-15-Amp-125-Volt-Light-Duty-Plug-Black-101-EP/301304861
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That said, if you spend extra finds towards an Audio Grade AC plug rather than a hardware store sourced product, it should be considered as a vital step to take for better audio performance.
The old supposed correct way to find "correct" polarity would be to plug the unit in and measure the chassis voltage with ac meter to ground, the supposed correct polarity would be the one that has the LEAST amount of ac on the chassis and then ground the chassis. What I am finding is the exact opposite my stuff sounds better the other way.
How old is the unit? 1950s/ 1960?s The old stuff often used an AC noise filter connected to one of the AC mains lines to chassis. Those old filter caps go bad and leak AC voltage to the chassis. That can skew the power transformer primary winding leads proper AC polarity orientation voltage measurement test for the lower of the two winding leads to the chassis measurement.
Look for the cap to see if one was used. Isolate, disconnect, it from the chassis and then do the polarity test.
Yes I would agree, but I have yet come across such problem, my vintage equipment i use does not have a Line to ground capacitor but a capacitor across the switch but none of this is what I asked about, I asked about YOUR experience/findings about polarity and sound, nothing more nothing less.
Guys nothing to worry about safety I am well versed in hi voltage 6kv audio repair, I have been repairing audio equipment for 25 years, I understand our utility very well.
Then why don't you just plug it in and see for yourself? You are the one that has to listen to it.
"Then why don't you just plug it in and see for yourself? You are the one that has to listen to it."
I was thinking along the same lines. Connect a turntable to it and find out which way gives you the least hum for one.
Things with two prong AC cords that are not polarized are usually fairly well isolated. But there is always a resistor and cap to keep the static electricity away. That causes a small amount of current to flow which can invade low level signals. Remember turntables ? In the owner's manual they told you if you are getting hum even when you got the ground hooked up to reverse the cord.
Things should be isolated enough that it doesn't matter, but nothing is perfect. And now, with a polarized AC cord, if they took and use the old resistor and cap on the hot side it would probably produce more hum. So then what do you want them to do ? If they put the resistors and caps o both sides of the lie there would be hum no matter which way you plug it in.
Maybe the answer is just to power all this stuff with DC.
A story about that, I think maybe in England. They used DC for a time. A serviceman was called because the TV would not work. He asked for a potato and stuck electrodes in it, and on DC one turns black or something. He simply reversed the power cord and it worked. I found it hard to believe they used DC, but then, whatever.
Really, with SMPS technology, DC power transmission is not all that much of a pain. It would eliminate all the inductive losses and the big heavy transformers. However, being solid state devices they would be more prone to failure and more susceptible to lightning strikes and whatever. But as technology advances and they fix those problems, we might see the day when power transmission is DC. It is possible now, but in the view of most people who now what they're doing, and I agree, it is not reliable enough at this point in time. There could be some changes made, for example huge filter capacitors that would limit their vulnerability to voltage spikes. Can't do that with AC.
But for now it is AC and is not going to change anytime soon. The whole system is designed for it and replacing it is like, well just too expensive.
Like electric cars. First of all nobody wants to just scrap their car and buy a Tesla. Then you need high current to charge the thing. If you are worried about CO2, more CO2 is emitted by generating electricity than cars, it would only make it worse.
France is said to be outlawing fossil fuel i about a decade. Well they happen to be a world leader in nuclear power. Ad if we start going electric we should have their engineers over here. I have never heard of them having an "accident". So they can pull this off. Thinking that the US is best at everything is an extremely outdated notion. In fact Russia has better weapons, we just have more of them. Other countries are doing things too and they are not all stupid.
So most of Europe is on 240/50 Hz. There was a discussion on Usenet on why the US went with 60 Hz. Most say it is so that the electric motors run faster and increase production in our factories. Of course that was many years ago. Now most machines run on DC and possibly a three (or more) phase convertor, or stepping motors.
Bottom line though, if people are worried about CO2, the only way to go is nuclear. Solar just isn't going to do it. Is solar going to power my AC at 240 volts at 15 or so amps in the middle of the night ? Ain't happening without a shit ton of batteries that are an environmental nightmare. Have any idea what kind of chemicals are in those things ? You certainly don't want them in your Cheerios.
Ironically, much of this old transformerless stuff will run just fine on DC unless you plug it in backwards. Might even run better. You make tube amps with DC filament supplies right ? Reduces hum and noise.
Enough.
Yes I would agree, but I have yet come across such problem, my vintage equipment i use does not have a Line to ground capacitor but a capacitor across the switch but none of this is what I asked about, I asked about YOUR experience/findings about polarity and sound, nothing more nothing less.
but none of this is what I asked about, I asked about YOUR experience/findings about polarity and sound, nothing more nothing less.
.
My response was given for the reason you may be finding why the piece of equipment sounds better with the higher chassis measured AC voltage. Just a guess the AC polarity orientation for the AC plug is correct. Nothing more, nothing less.
From my personal experience...
The lower of the two Vac measurements, from the Grounded Conductor/equipment Grounding Conductor, of the AC mains to the chassis of the equipment is the correct AC plug polarity orientation.
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Quote from Charles Hansen
1) Reversed AC polarity -- All power transformers have an inherent asymmetry to their construction. The primary winding comprises multiple layers, so that one lead is connected to the innermost windings and the other lead is connected to the outermost windings. This means that one lead has a higher coupling capacitance to the core of the transformer. Please remember that the AC supply is also asymmetrical, with the neutral lead essentially being at ground potential (assuming there is not a fault in the house wiring). The result is that one orientation will give a higher AC leakage current to the chassis of the amp (and worse sound) than the other orientation.
Not all transformer manufacturers use consistent markings on their transformers so that the correct orientation can be identified, and not all amp manufacturers pay attention to this even if the transformer is correctly marked. The result is that many audio products have a random chance of being correctly oriented. I would have to assume that the amp was modded to achieve the correct orientation, thereby achieving improved sound quality.
The correct way to do this is to swap the transformer leads, and not the connections at the IEC connector. The difference is that changing the leads at the IEC connector will move the power switch and fuse from the hot side of the line to the neutral side. While this *could* increase the liklihood of shock under a very unlikely set of circumstances, in my opinion the service technician *vastly* overstated the hazard that was introduced by this mod.
As long as you have voltmeter, the best way would be to be to measure the voltage from the power fuse to ground. You want the fuse on the hot side. I would replace the plug with a polarized version for safety. You might even considering replacing the old power cord as well. Tweaks are fine but safety should always take precedence.
I married the perfect woman. The downside is everything that goes wrong is my fault.
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