only one, what about the return path? as for high frequencies the last thing you want is enhanced conduction of hash in the GHz range...
I tried XY comparison method using two additional 20 m long extension cords on the bobbins, both measuring and listening DAC, preamplifier, power amplifier and loudspeakers combination. Working theory was that if a 'better' power cord can influence sound, a 'worse' one should as well. My audio components are described at post #256
Considering by what physical mechanism could different cords affect sound of equipment, I tried to cover what I could. That were two possible sources: noise and effect of different signal ground path affecting impossible to measure soundstage impression and details resolution.
For noise to possibly affect sound timbre as a correlated signal or to mask/change details, noise should have measurable value change. I can measure reliably to -180 dBV levels with several nV resolution.
Measuring output noise at DAC and preamplifier outputs, both connected first with standard power cord, and then each with 20 m extension cords, produced no measurable noise level or shape change or even temporary spikes except natural random variation around the same average value. Real time measurement method with no averaging was used first to observe any fast changes or spikes. Averaged noise level remained below -140 dBV or exactly -104.1 dBV in the 22 Hz to 22 kHz bandwidth, with volume control open in the used listening position.
Listening test were next. Tonal balance, timbre and exact positions on the soundstage were compared using several tracks (The Peppery Man – Natalie Merchant, Diamonds on the Soles of Her Shoes – Paul Simon, Hallelujah – Jeff Buckley).
To my best estimate, there wasn’t any change. This was an honest attempt to check if power cord can affect sound of my system. I listened with no prejudice or beliefs, trying hard to find a difference.
Those hearing distinct sound change with different cords, should be aware that premium power cords can make sound different by making it technically worse. In case of short circuit connected signal ground to power earth, audio signal between two audio components travels in parallel through interconnects cable ground and power earth ground. Signal distribution is determined by Ohm law. Usual interconnect shield resistance is about 0.05Ω. Two in parallel make 0.025Ω. Ordinary IEC power cord ground wire resistance is from 0.05 to 0.1Ω. Two in series have 0.1Ω. This provides that ¼ of signal power travels through power ground wires at 12 dB below main signal through RCA cable. As power ground wire is unprotected from noise, this is a point of EMI influence.
Using better cord with thick wires and lower resistance results in more of audio signal traveling through power cord ground wires. Assuming 0.01Ω for one ground wire, more of signal will travel through power cord ground wires than through RCA cables ground. Embedded shielding is of no help as ground wire is coupled to mains carrying wires with stray capacitance and inductance coupling. Shield is on the power cord outside.
Some ground breaker resistance is absolutely required and you may hear no change at all with power cords.
Considering by what physical mechanism could different cords affect sound of equipment, I tried to cover what I could. That were two possible sources: noise and effect of different signal ground path affecting impossible to measure soundstage impression and details resolution.
For noise to possibly affect sound timbre as a correlated signal or to mask/change details, noise should have measurable value change. I can measure reliably to -180 dBV levels with several nV resolution.
Measuring output noise at DAC and preamplifier outputs, both connected first with standard power cord, and then each with 20 m extension cords, produced no measurable noise level or shape change or even temporary spikes except natural random variation around the same average value. Real time measurement method with no averaging was used first to observe any fast changes or spikes. Averaged noise level remained below -140 dBV or exactly -104.1 dBV in the 22 Hz to 22 kHz bandwidth, with volume control open in the used listening position.
Listening test were next. Tonal balance, timbre and exact positions on the soundstage were compared using several tracks (The Peppery Man – Natalie Merchant, Diamonds on the Soles of Her Shoes – Paul Simon, Hallelujah – Jeff Buckley).
To my best estimate, there wasn’t any change. This was an honest attempt to check if power cord can affect sound of my system. I listened with no prejudice or beliefs, trying hard to find a difference.
Those hearing distinct sound change with different cords, should be aware that premium power cords can make sound different by making it technically worse. In case of short circuit connected signal ground to power earth, audio signal between two audio components travels in parallel through interconnects cable ground and power earth ground. Signal distribution is determined by Ohm law. Usual interconnect shield resistance is about 0.05Ω. Two in parallel make 0.025Ω. Ordinary IEC power cord ground wire resistance is from 0.05 to 0.1Ω. Two in series have 0.1Ω. This provides that ¼ of signal power travels through power ground wires at 12 dB below main signal through RCA cable. As power ground wire is unprotected from noise, this is a point of EMI influence.
Using better cord with thick wires and lower resistance results in more of audio signal traveling through power cord ground wires. Assuming 0.01Ω for one ground wire, more of signal will travel through power cord ground wires than through RCA cables ground. Embedded shielding is of no help as ground wire is coupled to mains carrying wires with stray capacitance and inductance coupling. Shield is on the power cord outside.
Some ground breaker resistance is absolutely required and you may hear no change at all with power cords.
Some of the amps were from Gryphon, MBL, Block Audio, Luxman, Pass, Viva, Constellation. Sometimes conditioners were used from Shunyata and Audioquest, but most times the amps were right into the wall outlet. No regenerators were used.
The high current Dragon is copper and silver, they might be in parallel, and the same on each leg of the AC, the low current Dragon is all silver according to Audioquest's web site.
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Tombo56 thank you for doing this test. To hear the improvement of a power cord it must be connected right to the piece of equipment like a plug in power cord with an IEC connector, The further you get away from the equipment the less the improvement. The first meter away from the equipment is the most important part of a cord, after 2 meters you get less improvement. I feel that this is why with your 20m extension cords you heard no change. Myself I think it is because of the inverse square law effect.I tried XY comparison method using two additional 20 m long extension cords on the bobbins, both measuring and listening DAC, preamplifier, power amplifier and loudspeakers combination. Working theory was that if a 'better' power cord can influence sound, a 'worse' one should as well. My audio components are described at post #256
Considering by what physical mechanism could different cords affect sound of equipment, I tried to cover what I could. That were two possible sources: noise and effect of different signal ground path affecting impossible to measure soundstage impression and details resolution.
For noise to possibly affect sound timbre as a correlated signal or to mask/change details, noise should have measurable value change. I can measure reliably to -180 dBV levels with several nV resolution.
Measuring output noise at DAC and preamplifier outputs, both connected first with standard power cord, and then each with 20 m extension cords, produced no measurable noise level or shape change or even temporary spikes except natural random variation around the same average value. Real time measurement method with no averaging was used first to observe any fast changes or spikes. Averaged noise level remained below -140 dBV or exactly -104.1 dBV in the 22 Hz to 22 kHz bandwidth, with volume control open in the used listening position.
Listening test were next. Tonal balance, timbre and exact positions on the soundstage were compared using several tracks (The Peppery Man – Natalie Merchant, Diamonds on the Soles of Her Shoes – Paul Simon, Hallelujah – Jeff Buckley).
To my best estimate, there wasn’t any change. This was an honest attempt to check if power cord can affect sound of my system. I listened with no prejudice or beliefs, trying hard to find a difference.
Those hearing distinct sound change with different cords, should be aware that premium power cords can make sound different by making it technically worse. In case of short circuit connected signal ground to power earth, audio signal between two audio components travels in parallel through interconnects cable ground and power earth ground. Signal distribution is determined by Ohm law. Usual interconnect shield resistance is about 0.05Ω. Two in parallel make 0.025Ω. Ordinary IEC power cord ground wire resistance is from 0.05 to 0.1Ω. Two in series have 0.1Ω. This provides that ¼ of signal power travels through power ground wires at 12 dB below main signal through RCA cable. As power ground wire is unprotected from noise, this is a point of EMI influence.
Using better cord with thick wires and lower resistance results in more of audio signal traveling through power cord ground wires. Assuming 0.01Ω for one ground wire, more of signal will travel through power cord ground wires than through RCA cables ground. Embedded shielding is of no help as ground wire is coupled to mains carrying wires with stray capacitance and inductance coupling. Shield is on the power cord outside.
Some ground breaker resistance is absolutely required and you may hear no change at all with power cords.
If you could make up a 2 meter power cord with solid core wire and plug it right into the equipment, that would be a good test. Thanks again for your work!
I have not seen this, but it might work well. Good thought.Maybe the safety ground is wired with silver litz to facilitate (encourage) the draining of the GHz hash away from the signal?
Okay. Do you find that the power cords affect pretty much all the amps in the same way, or different sound change for different amps? Also, what perceptually would you say sounds better with a cable that you would describe as sounding 'better?' Sound stage in some way, distortion in some way, FR, or what? In addition, what is the most common source device, vinyl, DAC, other?
Mark, a good aftermarket power cords makes the music more dimensional, it seems to come out of the speakers more and you can hear the space around the instruments. It also is like a fog or haze has cleared the room and sounds are clearer and more well defined. Professional reviewers can write about the change better than I can, I agree with what they hear, I’m sure you can find many reviews of power cords on line. All the amps improved the same way with a power cord change.
Most of the time the source was digital so comparisons of cords could be more easily made with the same songs and no record wear. We used a local digital storage or a streaming service like qobuz.
Also DAC’s respond very well to power cord changes even what I consider the best, the MSB reference.
Hmmm...
I think I understand the premises behind tombo's test: that a) if an effect is detectable with 6 feet of cord then it should be much more apparent (measurable) with 25 feet of cord and b) if "ordinary" cable is so bad in a 6 foot length, that terrible effect should be much more evident with 25 feet of cable. tombo was looking for a significant degradation in his test. This was not in evidence.
Your assertion about proximity seems predicted on a very local -- almost "topical" -- mechanism. The inverse square law might describe the character of the effect but not why that should be... how it works.
Your test proposal doesn't seem helpful in this regard. What might help would be to insert 20 feet of extension cord in between your fancy cord and the unit being powered.
And it might also be helpful to demonstrate just how "local" the effect is: Make up a series of very short fancy cables and test those as above. In other words, if you are correct, it just may be that 6 inches of high-end cord might be all you need to do the job. You are particularly well positioned to test this... at least in the golden ear realm. But it might also point to notions of how this might be and what is going on here.
That's just another audio marketing department myth.
The only small difference is that the last few meters can act as an interference antenna. (then changing the cord length or placement can change the interference susceptibility.
Yeah, I need to get some of those fancy power cords so that the sound will come out of the speakers more.
Right now the sound doesnt seem to be coming out of the speakers at all. Instead it seems to be coming from the wall between them, and worse yet, some of it comes from behind the wall. Particualary instruments that tend to be at the back of the orchestra.
So yeah, I need to do something to change all of that and get the sound to come right out of the speakers more. Thanks for the tip. New, fancy, expensive power cords. Yeah.
Probably doesn't mean that. Hopefully not anyway. Perhaps improvement in 'the space around the instruments' might have been more the point?
Regarding soundstage, Topping D90 had more of it than Benchmark DAC-3. Despite that it was still possible to hear what was wrong with D90.
Changing the subject for a moment, if anyone listened to the same one of the YouTube power cord comparisons I did, with A and B examples, 'A' sounded rather bright on my laptop, and 'B' sounded more subdued and maybe a bit time-smeared, kind like oil-filled caps can do (or however one would like to describe those two different example sound effects). Didn't listen on the big system since it was only YouTube lossy compressed quality. Did anyone else listen to that video?
Regarding soundstage, Topping D90 had more of it than Benchmark DAC-3. Despite that it was still possible to hear what was wrong with D90.
Changing the subject for a moment, if anyone listened to the same one of the YouTube power cord comparisons I did, with A and B examples, 'A' sounded rather bright on my laptop, and 'B' sounded more subdued and maybe a bit time-smeared, kind like oil-filled caps can do (or however one would like to describe those two different example sound effects). Didn't listen on the big system since it was only YouTube lossy compressed quality. Did anyone else listen to that video?
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Not at all. Just saying some things are at least partially audible despite a laptop, and despite lossy compression. That was one subject regarding YouTube power cord comparisons.
Moving along then to something a bit different, guess its that I keep finding out now and then what I used to think was about as good as reproduction gets on a really good system, actually it could have been a little more good than I thought. Didn't expect it, but I only can know the best reproduction I have heard. Otherwise I may assume a limit on recording quality or something else along those lines (which can be a problem too of course).
Maybe like having a great expanded gamut and color calibrated LCD display that seems about as good as monitors can get. Then one day I see a better monitor that does more realistic black. Or maybe I see a digital camera image where the color of my rug looks really accurate (that one hasn't happened yet, unfortunately). Probably the idea is clear enough though. We only know some things as well as they can be known from prior experience. For me, that includes how good I know how to do on the main reproduction system as of today. Wouldn't be surprised if all our systems could be audibly improved to some degree, whether or not we would like to believe it.
Moving along then to something a bit different, guess its that I keep finding out now and then what I used to think was about as good as reproduction gets on a really good system, actually it could have been a little more good than I thought. Didn't expect it, but I only can know the best reproduction I have heard. Otherwise I may assume a limit on recording quality or something else along those lines (which can be a problem too of course).
Maybe like having a great expanded gamut and color calibrated LCD display that seems about as good as monitors can get. Then one day I see a better monitor that does more realistic black. Or maybe I see a digital camera image where the color of my rug looks really accurate (that one hasn't happened yet, unfortunately). Probably the idea is clear enough though. We only know some things as well as they can be known from prior experience. For me, that includes how good I know how to do on the main reproduction system as of today. Wouldn't be surprised if all our systems could be audibly improved to some degree, whether or not we would like to believe it.
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