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Hi,
Do old vintage power cords better than say a new Pangea power cord you see in Audio Advisor?
In the new issue of Absolute Sound there is a new article called (Tip of the month) AC Polarity.
In this article the writer in a quest for better sound explains that the power transformer leaks a small amount of AC voltage from the primary that can be measured on an isolated chassis that when minimized will greatly improve your sound. He does this measurement by measuring the chassis voltage, with interconnects disconnected then measuring again with the power outlet plug flipped upside down or prongs reversed in the AC outlet. The lower voltage measured on the chassis providing the least distortion.
To do this he takes a gray (cheater plug), attaches the ground wire to ground and flips this plug upside down in the outlet to attain 2 different chassis voltages.
I think it is fair to list this question in (vintage) because most of my vintage stuff has old 2 prong plugs with no ground prong on the plug. To do this test he files one plug prong down, the larger wider one, to be able to flip the gray adapter plug, with the newer grounded plug inserted.
I'm not understanding this as how one side of an outlet will produce a lower voltage on one side as it is an alternating current.
How will this article sit with the people that prefer the worlds most exspensive cables?, of which Absolute Sound makes a lot of revenue on. You can't flip a grounded plug upside down with that ground plug on it. Will there be a rush by Hi-fi nuts to hardware stores for those 25 cent gray plugs?
I need some schooling on this one if any of you have the time......thanks.....Mark Korda.
Follow Ups:
nt
You asked a question and I'll do my best to answer it. It's called "absolute phase". It's really not that difficult. Imagine your loudspeaker connection. The speaker will produce sound when connected either way, but the correct way is clearly better. The easiest way to measure is with a volt meter. With the amp powered up, measure from the metal chassis to earth ground. Reverse the outlet plug and remeasure. The orientation that give the least amount of voltage readings should give the best sound.
I have an ST-35 as well BTW. You also may get why I checked out on answering questions years ago on the asylum. It isn't called the asylum for nothing. It'll drive you crazy if you aren't already. Lol
I agree with Sam that measuring an older plug with two blades only requires reversing the plug while measuring both positions.
However, with newer grounded plugs I make three readings. First in the normal position with the ground pin (3rd) inserted. Then I measure with a "cheater" plug (3 into 2), now ungrounded, with the same orientation. Lastly I reverse the cheater plug.
I've found I cannot predict which orientation will give the lowest voltage reading, experimenting is the only way.
"The piano ain't got no wrong notes." Thelonious Monk
It seems like I remember seeing some HQ cords have a removable ground terminal.
Lots of playing around to get the best sound, but so worth it!
"He does this measurement by measuring the chassis voltage, with interconnects disconnected then measuring again with the power outlet plug flipped upside down or prongs reversed in the AC outlet. The lower voltage measured on the chassis providing the least distortion."
I did this 25 years ago before three wire grounded plugs were common. I was more concerned that there could be dangerous ACV on the chassis. Further, any AC voltage on the chassis causes current to travel through the interconnect cables since the two chassis of the connected components are at different voltage potentials. This is not only dangerous, but it also causes noise and hum. All this was solved by the introduction of three wire power cables and by not using the chassis as ground, with the exception of one location where the green ground wire from the power cord is connected.
Some consumer gear in the 1950s and 1960s used the chassis as ground throughout the unit. This creates many ground loops and the only way to fix the situation is to make a ground bus. Everywhere the chassis is used as ground, that connection should then go to the bus which is only connected to the chassis where the green wire from the power cable is connected. Any older gear that reaches my workbench receives a three wire cable before any other task is started. If the chassis was used as ground that is rectified too by installing a ground bus.
Just saw that YOU actually did give a good answer. Sorry that I didn't see prior to my reply. My brain cells were about to melt after reading the other replies. I'm ready for a shot of Makers Mark now.
Absolute Phase, I'll etch that in Samstone.
Stone, that was the easiest answer, thanks. All the rest of you too.
One thing I found out about the Dyna-35 was that the cage was too small. It touches my quad cap, same size as the original, and in some instances the transformers. I'm going to re drill the mounting holes, lower. I had a 5 pound York barbell plate on my cage to stop a hum until Steve from Texas told me about the cage thing. Thanks for the info from all. This is the stuff you can't easily find in a book.....Mark K.
First of all, putting a $30 Pangea cord in context with "the world's most expensive cables" is a bit of a joke.
Today, virtually all high powered amps must be grounded to pass code. What I've experienced with using a range of aftermarket power cords, both commercially available and DIY, is improved ability to transfer necessary current (yes, Virginia I use 20A dedicated circuits for my amps) and multiple ways to minimize RMI/RFI interference. The results are better dynamic punch and clarity especially at the top.
While turntables don't require current, they do benefit from noise rejection. Long ago, I replaced the dinky lamp cord attached to my Ariston RD-11s turntable with shielded 14 gauge Belden cable using a high quality plug. That indeed reduced noise in my system.
You don't really have to measure at the line (requires 20dB pads for most data acquisition cards) but you can measure the power supply voltages and the and look for noise - and perhaps the ground connections - signal and chassis grounds.Each component power supply is designed differently - so it is useful to measure the signal grounds for noise insertion along each component. Sometimes enhanced by bad cables or connectors.
"The hardest thing of all is to find a black cat in a dark room, especially if there is no cat" - Confucius
Edits: 02/01/17
Are you referring to noise generated after the outlet?
I was an electrician for about 4 years and between that outlet and the panel there are a lot of connections and wires wrapped in bundles - lottsa EMF there. So it would seem to me that any noise cancelling effects would have to be at that outlet point. Like a power reserve much like a stereos filtering caps.
Otherwise a good 12-14 gauge cord should be fine. being the rest of your house is wired with 14 gauge.
Are you referring to noise generated after the outlet?
Before and after. Your system is a source of EMI/RFI noise. Myriad other devices on the power line are sources of EMI/RFI noise. All of it. :)
So it would seem to me that any noise cancelling effects would have to be at that outlet point.
Indeed there are enthusiasts who invest considerable funds into Oyaide outlets. As for me, I use heavy duty Leviton hospital grade outlets for their firm connectors.
Otherwise a good 12-14 gauge cord should be fine. being the rest of your house is wired with 14 gauge.
I'll continue to disagree with both assertions.
I've found audible benefits in many systems using aftermarket cabling of larger gauge and apparently you didn't pay attention to details in my post. Hint: the audio system has its own lines. And, FWIW, I had an electrician add a line to the closet in the garage which is also 12 gauge. :)
I never heard a difference in various power cords. I did hear a difference late at night. I assumed the 120 VAC line noise was reduced in my NYC setting after people went to bed. (I left NYC for MI a few years ago).I now install a Corcom line filter on my amplifiers.
Edits: 01/31/17
Other components in your system are likewise effected or generate RFI noise themselves like all digital critters.
Filters alone, however, with high powered amplifier don't address current issues.
Hi you guys,
All I'm trying to find out is why one side of the outlet delivers more or less voltage than the other side. I have not measured the difference yet on my Dyna-35 which has an old style plug with no ground prong and plug blades the same size.It does work fine either way it's plugged in.
I'm just trying to figure out the science behind this guys tip in Absolute Sound about turning your power cord plug upside down and why there are different voltages involved measured from the chassis.
I hope someone finds the article. Thanks for any info at all though. It's greatly appreciated....Mark K.
The situation you describe is primarily the result of asymmetric mains leakage to the chassis due to PT construction idiosyncrasies and/or the presence of a "death cap(s)". Personal experience indicates that there is indeed benefit to orienting the mains plug for minimum AC voltage betw chassis and electrical system ground while powered up AND coordinating the orientation of equipment to be interconnected such that all equipment is at lowest potential to ground while in isolation (before interconnects are added).
With everything properly oriented, I hear (and can measure) reduced noise and hum and not necessarily better sound as might be described as "higher highs", "blacker blacks", improved "PRAT" etc.
Obviously, it's usually bad form to defeat the grounding feature of 3 prong plugs by improperly using "cheaters".
Here are my guesses. First guess, it isn't the AC coming in, it is the unit's power transformer which isn't perfect. The chassis ground is the center tap of the secondary, which is going to have slightly different inductance to the poles.
Second guess, the AC may be a contributing factor if the waveform is asymmetrical.
Regarding the adding of grounded plugs to vintage equipment. I always do this, but leave it so that it can be detached. I have had a few instances that removing the third wire ground at the equipment end is the only way I could get rid of audible digital noise.
I'm a little slow today Mark, but are asking if there is any difference between measuring voltage between the hot and ground leg of the same receptacle? And this is because you have a non polarized older style plug?
Just a hint - don't get to wrapped up into those articles since you are dealing with a piece that was designed with that plug in mind. newer units do have polarized plugs BUT ! I can't tell you how many receptacles I've changed out over the years where the polarity was incorrectly hooked up. So you win a few and loose a few.
It sure would be nice if there was a shielded version of
14/2 or 12/2 house wire avail. for a dedicated line.Outlets use 20A circuits, lighting, 15A.
Edits: 01/31/17
One of my power cord purveyors, JPS Labs sells UL and CSA listed cable for in wall use, although it's 10 gauge.
E-stat:"(yes, Virginia I use 20A dedicated circuits for my amps)"
Airtime: "being the rest of your house is wired with 14 gauge"
FYI, A 20 amp circuit by code requires 12awg cable.
actually isn't BX cable shielded?
Good point
Hi, All great points! When I redefined the question a little you guys had some great info. I need to do some multimeter tests for my own curiosity but will probably install the 3 prong plug if I don't hear anything great in the sound change as the article implies. Thanks so much. As far as cables and cords go I like to have the (magic) explained before I start throwing money around.....Mark K.
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