From a previous post on this forum -
Regardless of what certain 'experts' (without the benefit of actual experimentation) oppine, there are valid technical objective measures that will change the subjective capabilities of a powercord.
In the States, it is easy to get a subtantial improvement over the typically supplied OEM stock cord by replacing them with Volex 17604 IEC terminated cords at less than $1/ft. These have 3 14ga cabled wires with plastic fillers to space the shield away from the wires. This results in far less capacitive coupling to ground than an apparently similar cords (such as those from Unicable that lack the fillers) and will result in very different subjective perceptions. The voltage rating of cords used must be appropriate for your line voltage, i.e. 240vac as opposed to the 120vac here in North America.
Certainly, there is much voodoo associated with aftermarket cords... but there are construction details that change subjective perceptions that correllate to measureable objective measures.
1. As Pinkmouse said, use appropriately rated cords, with a large gauge to minimize both danger and resistance.
2. Minimize capacitive coupling to ground by spacing the shield away from the line and neutral wires, if you use a shield. This is easiest to do, but I'm not familiar with what is available in Europe, but it should be possible to find premade cordage in Europe who's shield is spaced away from the wires
3. Maximize the line to neutral capacitace by using multiple twisted pairs or a star-quad configuration for the line and neutral wires, as that capacitance acts as a noise filter, and those geometries will minimize the effects of external emi and rfi interference, especially if your cord lacks a shield.
All I can say is that I've actually compared cords, its inexpensive as starquad cords are readily available, and the above 'guidelines' have worked for me.
For anyone who's knowledge tells them 'if the resistance...', I can only suggest they obtain a Volex 17604 from Newark.com and the equivalent from Unicable, #6450 -
http://www.unicable.com/
and conduct their own statistically significant, double blind test. The cords show equal resistance, but you should change their premoulded plugs to whatever, for consistency (I used Marincos).
I assume there is a reason (other than 'audiophilia') that cordage manufacturers (Belden, CDT, Alpha, Northwire) use fillers around the cabled conductors on shielded cables. I suspect that those reasons are the very same ones that account for the subjective differences I (and everyone else who has compared the 'sound' without knowing which is which) can detect, and consistently identify.
I've no definitive answers, but I do know that its not resistance uber alles.
Regardless of what certain 'experts' (without the benefit of actual experimentation) oppine, there are valid technical objective measures that will change the subjective capabilities of a powercord.
In the States, it is easy to get a subtantial improvement over the typically supplied OEM stock cord by replacing them with Volex 17604 IEC terminated cords at less than $1/ft. These have 3 14ga cabled wires with plastic fillers to space the shield away from the wires. This results in far less capacitive coupling to ground than an apparently similar cords (such as those from Unicable that lack the fillers) and will result in very different subjective perceptions. The voltage rating of cords used must be appropriate for your line voltage, i.e. 240vac as opposed to the 120vac here in North America.
Certainly, there is much voodoo associated with aftermarket cords... but there are construction details that change subjective perceptions that correllate to measureable objective measures.
1. As Pinkmouse said, use appropriately rated cords, with a large gauge to minimize both danger and resistance.
2. Minimize capacitive coupling to ground by spacing the shield away from the line and neutral wires, if you use a shield. This is easiest to do, but I'm not familiar with what is available in Europe, but it should be possible to find premade cordage in Europe who's shield is spaced away from the wires
3. Maximize the line to neutral capacitace by using multiple twisted pairs or a star-quad configuration for the line and neutral wires, as that capacitance acts as a noise filter, and those geometries will minimize the effects of external emi and rfi interference, especially if your cord lacks a shield.
All I can say is that I've actually compared cords, its inexpensive as starquad cords are readily available, and the above 'guidelines' have worked for me.
For anyone who's knowledge tells them 'if the resistance...', I can only suggest they obtain a Volex 17604 from Newark.com and the equivalent from Unicable, #6450 -
http://www.unicable.com/
and conduct their own statistically significant, double blind test. The cords show equal resistance, but you should change their premoulded plugs to whatever, for consistency (I used Marincos).
I assume there is a reason (other than 'audiophilia') that cordage manufacturers (Belden, CDT, Alpha, Northwire) use fillers around the cabled conductors on shielded cables. I suspect that those reasons are the very same ones that account for the subjective differences I (and everyone else who has compared the 'sound' without knowing which is which) can detect, and consistently identify.
I've no definitive answers, but I do know that its not resistance uber alles.
li_gangyi said:
ABSOLUTELY!! The human factor that might prompt one to conduct an actual experiment rather than play that (evidently) obligatory role of jaded cynic in a sophomore(ic) epistemology seminar....
dohz...everything has got Human Factor as an answer...you noe McDonalds?? they use a food tray to minimise spillage...the nthe human factor comes in...it does not work properly when you drop the whole thing on the floor~!!!
On the subject of power cords and sound quality, how about the recording process? Is it possible to tell which recordings were conducted with "good," burnt-in power cords?
It comes to mind that some audio debates could be resolved (more likely escalated) if A/B/X recordings could be made to exemplify the differences in the sound caused by "good" power cords ("good" capacitors, "good" resistors, "good" whatever).
Of course, those listening to the A/B/X recording with "bad" components would not hear "as well" the difference in sound quality. But, shouldn't the difference be noticeable (even on a "bad" system)? And would anyone tell which way the X recording was conducted with A: "good" components or B: "bad" components.
And , of course, a lot of music is recorded with "bad" components. If one wished to truly improve the sound quality of reproduced music, then all of us would benefit from having recording studios convert over to "good" power cords. And if they are already using them, that would be interesting to learn. Perhaps they are using the good ones (the same ones most of use).
JF
It comes to mind that some audio debates could be resolved (more likely escalated) if A/B/X recordings could be made to exemplify the differences in the sound caused by "good" power cords ("good" capacitors, "good" resistors, "good" whatever).
Of course, those listening to the A/B/X recording with "bad" components would not hear "as well" the difference in sound quality. But, shouldn't the difference be noticeable (even on a "bad" system)? And would anyone tell which way the X recording was conducted with A: "good" components or B: "bad" components.
And , of course, a lot of music is recorded with "bad" components. If one wished to truly improve the sound quality of reproduced music, then all of us would benefit from having recording studios convert over to "good" power cords. And if they are already using them, that would be interesting to learn. Perhaps they are using the good ones (the same ones most of use).
JF
there is a bit of time difference when swapping power cords...and manufacturers might say putting a switch spoild the sonic differences in the power cables...
li_gangyi said:
Guess I had something a little more sophisticated in mind.
Someone could conduct a well thought out way to exemplify the difference in sound quality of aspects of audio (during the recording process). Of course, some people will debate the merits of such a test.
(I can appreciate one of Sully's points--that it's challenging to find ways to get constructive thinking going on about such issues. Deconstruction seems to prevail. In the Big picture, entropy is increasing, right? So deconstruction just follows the general trend. It's good to get these things straight. At least, I know that it's nothing personal.)
JF
Re: Re: Re: Interpreting results
Konnichiwa,
Are you familiar with any published DB Test offering such large sample sizes? I know few tests that have either sufficient participants or tries per participant outside serious research, such as perceptual coding like MP3.
Sayonara
Konnichiwa,
Rob M said:
Are you familiar with any published DB Test offering such large sample sizes? I know few tests that have either sufficient participants or tries per participant outside serious research, such as perceptual coding like MP3.
Sayonara
Re: Interpreting results
No, I'm not, but I'm no expert on this stuff. You said that tests with sample sizes less than several hundred couldn't be taken seriously, which I found puzzling. In fact, a sample size of 30 or so should be enough to find an effect as strong as the ones you mentioned. Whether any such tests have been performed is another question, which I bet someone else here can answer.
Kuei Yang Wang said:
No, I'm not, but I'm no expert on this stuff. You said that tests with sample sizes less than several hundred couldn't be taken seriously, which I found puzzling. In fact, a sample size of 30 or so should be enough to find an effect as strong as the ones you mentioned. Whether any such tests have been performed is another question, which I bet someone else here can answer.
pmkap said:
Im no great expert o the subject, but I had a few interesting conversations with people who make cable. Particularly when it comes to power chords I think that the fillers are there mostly to maintain the cable geometry. With power cords that means keep it round, with HF-AC cables it also gets into other issues. I know that over the last decade an awful lot of energy has gone into finding out what happens to the filler and sheath materials when they are heated to a few thousand degrease. CL-2 and plenum ratings have greatly influenced cable manufacturing.
David,
Yes, you are undoubtedly correct. I should have realized that the typical fillers are not specifically for spacing the shield away from the line and neutral, as cordage without shields often have fillers.
I guess that it was fortuitous that I found nominally equivalent cords, whos construction difference was that shield spacing. An additional experiment further led me to the conclusion that powercords with high capacitve coupling 'to ground', for lack of a better word, simply sucked. In an effort to make the powercord equivalent to a large X2 and Y2 cap(s), I made a pc from a 12 16ga teflon wire (6 hot, 6 neutral), with the ground via foil and copper shielding. It exactly duplicated the wretched (albeit subjective) qualities of the Unicable. When the shielding was removed from the experiment, and ground established with a single 12ga, loosely spiraled in the opposite direction from the cabled wires direction, the powercord was 'peachy', lacking those subjective characteristics which I now believe is asscociated whith 'intimate' shields. Further, I believe that these subjective qualities are conveyed by a surfeit of distributed capacitive coupling to ground.
I may not know what makes a great powercord, but I do know one of the things that can make a bad powercord. I'll not prejudice anyone with those subjective characterizations, and can only suggest that anyone who wishes to test the hypothesis that 'resistance is all', conduct their own experiment with a Volex 17605 and Unicable 6450, using them to energize a poweramp.
Yes, you are undoubtedly correct. I should have realized that the typical fillers are not specifically for spacing the shield away from the line and neutral, as cordage without shields often have fillers.
I guess that it was fortuitous that I found nominally equivalent cords, whos construction difference was that shield spacing. An additional experiment further led me to the conclusion that powercords with high capacitve coupling 'to ground', for lack of a better word, simply sucked. In an effort to make the powercord equivalent to a large X2 and Y2 cap(s), I made a pc from a 12 16ga teflon wire (6 hot, 6 neutral), with the ground via foil and copper shielding. It exactly duplicated the wretched (albeit subjective) qualities of the Unicable. When the shielding was removed from the experiment, and ground established with a single 12ga, loosely spiraled in the opposite direction from the cabled wires direction, the powercord was 'peachy', lacking those subjective characteristics which I now believe is asscociated whith 'intimate' shields. Further, I believe that these subjective qualities are conveyed by a surfeit of distributed capacitive coupling to ground.
I may not know what makes a great powercord, but I do know one of the things that can make a bad powercord. I'll not prejudice anyone with those subjective characterizations, and can only suggest that anyone who wishes to test the hypothesis that 'resistance is all', conduct their own experiment with a Volex 17605 and Unicable 6450, using them to energize a poweramp.
Re: Re: I should know better ....
I don't know in which country you live, but your electrical building code is at "electrical third world" standard!
In most of the European Union the neutral and the ground HAVE to be separate. Any attempt to short or to connect them together would immediately trip the safety switch of the house! Any Italian, German and French reader will know what I'm talking about...
In my previous post I stated very clearly that we would assume that no PC was seriously flawed or grossly inadequate. What you describe as an experience is pure madness, no person in his right state of mind would ever do that.
IMHO, the VOLTAGE fluctuations that can occur in the AC line are much more audible than any esoteric cable design.
I maintain that, under normal circumstances (please see above), audibility of PC sound is several orders of magnitude below ANY other element in your system, and I'm being generous because my real personal opinion is that this is nothing but snake oil.
sully said:
I don't know in which country you live, but your electrical building code is at "electrical third world" standard!
In most of the European Union the neutral and the ground HAVE to be separate. Any attempt to short or to connect them together would immediately trip the safety switch of the house! Any Italian, German and French reader will know what I'm talking about...
In my previous post I stated very clearly that we would assume that no PC was seriously flawed or grossly inadequate. What you describe as an experience is pure madness, no person in his right state of mind would ever do that.
IMHO, the VOLTAGE fluctuations that can occur in the AC line are much more audible than any esoteric cable design.
I maintain that, under normal circumstances (please see above), audibility of PC sound is several orders of magnitude below ANY other element in your system, and I'm being generous because my real personal opinion is that this is nothing but snake oil.
Re: Re: Re: I should know better ....
Why would it do that? The safety ground doesn't carry any current except under fault conditions (other than small leakage currents due to capacitive coupling). We have GFCI (Ground Fault Circuit Interruptors) here too that are required in most new homes and they work just fine with neutral tied to safety ground.
se
m.parigi said:
Why would it do that? The safety ground doesn't carry any current except under fault conditions (other than small leakage currents due to capacitive coupling). We have GFCI (Ground Fault Circuit Interruptors) here too that are required in most new homes and they work just fine with neutral tied to safety ground.
se
li_gangyi said:
How the GFCIs typically work here is they monitor the current on hot and neutral. Under normal conditions there will be as much current flowing through the hot as the neutral. In the event of a fault, there will be more current flowing through one than the other and once a certain differential threshold is reached, the circuit trips.
se
li_gangyi said:
Think I might have misread you here.
What do you mean by "it" with regard to carrying return current?
se
We're getting off topic here!
The safety switch is known in Europe as a "differential" switch and in Italy it is tripped by a current of 15mA (this threshold is mandated by law).
As to connecting neutral and ground together, in Europe it's against the law, not to mention the issues we're discussing about.
Now, that is something that, at least theoretically, COULD affect the sound, because you'd then be losing some of the shielding effect of the chassis (grounded) and you would lose an electrical reference point.
However, changing the PC wouldn't still be doing anything to the sound, because the issue wouldn't be solved.
I'm suggesting a simple experiment to the skeptics.
Drive an iron bar (the kind used for reinforcing concrete is perfect) into the ground of your garden (yard for the US friends) for at least 50-80 cm. (2-3 feet), leaving a small portion of it protruding out of the ground.
Electrically connect a large section cable to the bar and run it into your house to your equipment. You should be able to connect it to all of your gear or at least to the power amp.
If you want to A/B test it, get a rocker switch and put on one side the "regular" ground coming from your outled and on the other side the "homegrown" ground.
You'll be amazed at the differences in sound!!! You can even have a friend to operate the switch without you looking, so that you can rule out subjectivism...
The safety switch is known in Europe as a "differential" switch and in Italy it is tripped by a current of 15mA (this threshold is mandated by law).
As to connecting neutral and ground together, in Europe it's against the law, not to mention the issues we're discussing about.
Now, that is something that, at least theoretically, COULD affect the sound, because you'd then be losing some of the shielding effect of the chassis (grounded) and you would lose an electrical reference point.
However, changing the PC wouldn't still be doing anything to the sound, because the issue wouldn't be solved.
I'm suggesting a simple experiment to the skeptics.
Drive an iron bar (the kind used for reinforcing concrete is perfect) into the ground of your garden (yard for the US friends) for at least 50-80 cm. (2-3 feet), leaving a small portion of it protruding out of the ground.
Electrically connect a large section cable to the bar and run it into your house to your equipment. You should be able to connect it to all of your gear or at least to the power amp.
If you want to A/B test it, get a rocker switch and put on one side the "regular" ground coming from your outled and on the other side the "homegrown" ground.
You'll be amazed at the differences in sound!!! You can even have a friend to operate the switch without you looking, so that you can rule out subjectivism...
Re: Re: Interpreting results
Konnichiwa,
I must conclude that you willfully misinterpret waht I have been writing.
I suggested that in order to qualify the existence of comparably small differences (eg audio or power cables) a very large sample size is required, if we wish to analyse the data to a .05 level of significance.
I provided entierly DIFFERENT items as a "pre-test" of the setup and listeners, simply to ensure tht there are no fundamental errors in the test setup, just as you would verify any other test setup that attempts to quantify or qualify an unknown but suspected effect with a suitable KNOWN effect. This is basic a scientific approach, no more and no less.
AND at one of the DB Tests I was present at I was able to illustrate that the test-setup was not discriminating enough to allow the participants to show a statististically significant identification of even out of phase channels, when analysed to .05 significance, though at .2 significance all participants showed a stististically significant identification.
As this was done after the main test some of the lack of discrimination can easily be accounted for by listener fatigue, yet in less formal tets of my own I noticed that often people fail even the basic test of discrimination in a drastically different audio system/setup compared to their own.
All in all the use of DB testing without accounting for listener fatigue, attention span (how many times can you listen to the same excerpt of music before your attention shuts down?) AND together with small to very small sample sizes is not productive in qualifying small differences.
Any number of null results have been laboriously produced, documented and published to illustrate nothing more than either a lack of sufficient statistical and human auditory/nervous system knowledge (the favourable hyphotesis) or a deliberate intent at deception (the unfavourable hyphothesis).
Whichever hyphotesis is true, practically non of the DB Tests available and quoted in the public domain have sufficient statistical power, either singly or when combined to illustrate anything WHATSOEVER on the subject of the audibility of (for example) differences in Interconnect or Speaker cables, never mind power cables.
BTW, this is not as such a rejection or condemnation of Double Blind Testing as a scientific methode, but rather a condemnation of the either deliberate or ignorant MISUSE of DB Testing by certain pseudoscientific sharlatans who have their own agendas and issues to promote and zero interest in the actual truth.
Sayonara
Konnichiwa,
Rob M said:
I must conclude that you willfully misinterpret waht I have been writing.
I suggested that in order to qualify the existence of comparably small differences (eg audio or power cables) a very large sample size is required, if we wish to analyse the data to a .05 level of significance.
I provided entierly DIFFERENT items as a "pre-test" of the setup and listeners, simply to ensure tht there are no fundamental errors in the test setup, just as you would verify any other test setup that attempts to quantify or qualify an unknown but suspected effect with a suitable KNOWN effect. This is basic a scientific approach, no more and no less.
AND at one of the DB Tests I was present at I was able to illustrate that the test-setup was not discriminating enough to allow the participants to show a statististically significant identification of even out of phase channels, when analysed to .05 significance, though at .2 significance all participants showed a stististically significant identification.
As this was done after the main test some of the lack of discrimination can easily be accounted for by listener fatigue, yet in less formal tets of my own I noticed that often people fail even the basic test of discrimination in a drastically different audio system/setup compared to their own.
All in all the use of DB testing without accounting for listener fatigue, attention span (how many times can you listen to the same excerpt of music before your attention shuts down?) AND together with small to very small sample sizes is not productive in qualifying small differences.
Any number of null results have been laboriously produced, documented and published to illustrate nothing more than either a lack of sufficient statistical and human auditory/nervous system knowledge (the favourable hyphotesis) or a deliberate intent at deception (the unfavourable hyphothesis).
Whichever hyphotesis is true, practically non of the DB Tests available and quoted in the public domain have sufficient statistical power, either singly or when combined to illustrate anything WHATSOEVER on the subject of the audibility of (for example) differences in Interconnect or Speaker cables, never mind power cables.
BTW, this is not as such a rejection or condemnation of Double Blind Testing as a scientific methode, but rather a condemnation of the either deliberate or ignorant MISUSE of DB Testing by certain pseudoscientific sharlatans who have their own agendas and issues to promote and zero interest in the actual truth.
Sayonara
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