I Believe in Power Cords
- Thread starter mep
- Start date
power cords are one thing and I believe they make a positive difference over the stock 14 guage or whatever wire you typically see. OT perhaps, Speaker wire is a whole different matter. Any version regardless of metallurgy, guage, dielectric, winding pattern ect will have varying performance depending on master to slave impedance, namely that of the amp to speaker. That is why a multi articulate interface's makes sense...ie MIT
I have what the manufacturer of each individual piece provided. I am going to have custom cords made to the exact length to clean up my equipment rack but they, too, will be of the "garden variety".
When I originally purchased all of the expensive cords, I had just added some power conditioners/re-generators and there was a real difference in the sound quality. When I then added the power cords, I could near no difference from the cords. And I am a big believer in blind testing (for me) as I know I am heavily influenced by expectation bias. So a friend randomly switched cords in and out and I could only guess as I heard zero difference.
While I don't think one set of competently built power cords sound any different than any other set of competently built power cords, I am not suggesting that others may not hear differences --- but I don't
garylkoh
WBF Technical Expert (Speakers & Audio Equipment)
Yes, that puzzles me too. I don't understand why a power cord (if well designed) would reduce the hum on the transformer. I checked the Pangea AC-9 on their website, and there certainly isn't anything exotic going on. I know that there are power cords with carbon or palladium conductors and these would have significant impedance that would then reduce the DC standing current at the transformer. If it's got high enough capacitance, that could also introduce sufficient impedance at ~0Hz to make a difference. I don't see either of in the powercord that mep picked out.
Upgrading the wall sockets, polishing the metal interfaces of the power cord, applying deoxit would probably do the trick.
Otherwise, as Frantz has pointed out, better power conditioning strategies. It would seem that fallibilities (if any) would reside at the vulnerable contact points rather than any quality of the wire or shielding as long as it was a generally appropriate gauge.
Of course, you could just rip out the copper wire from the wall and hard wire/solder it to your components.
Audiophile placebo effect (i.e. improving the signal to noise ratio of the distressed audiophile mind) can't be discounted, even Kaiser has incorporated and acknowledged the placebo effect into its practice strategies.
Otherwise, as Frantz has pointed out, better power conditioning strategies. It would seem that fallibilities (if any) would reside at the vulnerable contact points rather than any quality of the wire or shielding as long as it was a generally appropriate gauge.
Of course, you could just rip out the copper wire from the wall and hard wire/solder it to your components.
Audiophile placebo effect (i.e. improving the signal to noise ratio of the distressed audiophile mind) can't be discounted, even Kaiser has incorporated and acknowledged the placebo effect into its practice strategies.
This has been a great thread, I really enjoyed everybody's posts. If anybody is interested I'm using Silver High Breed power cables on my amp and preamp and a Shunyata Venom 3 on my cd player. I originally had two PS Audio Prelude power on my power amp and didn't really hear much of a difference except for a quieter background. When I switched to the Silver High Breeds the sound was more open with more extended highs, more detail top to bottom, the background was even more quieter, and my soundstage was pulled back a bit. Here is a picture of one of the Silver High Breeds.
garylkoh
WBF Technical Expert (Speakers & Audio Equipment)
It was an actual transformer buzz that mep was experiencing - nothing to do with audiophile placebo effect.
There are well-known causes of transformer buzz, and besides bad design of the transformer, the rest are all mains related. That the power cord that mep picked fixed it may have been a happy coincidence, but I'd like to understand the coincidence so that others here may benefit. I remember lloydelee having the problem for months with no resolution. What we learn here could be extremely helpful.
There are well-known causes of transformer buzz, and besides bad design of the transformer, the rest are all mains related. That the power cord that mep picked fixed it may have been a happy coincidence, but I'd like to understand the coincidence so that others here may benefit. I remember lloydelee having the problem for months with no resolution. What we learn here could be extremely helpful.
+1. I am a skeptic of audible benefits of power cords except in cases where something else is wrong, but there was a clear improvement here. I'd like to know why.
Although Don, what about a house that seems to have adequate earth-ground and yet improving that can result in better noise floor from equipment.
Yep something I have experienced myself with a building regulation electrician examining my mains.
I appreciate the importance of technical-reference ground, just showing an example of how the default installation was fine in theory and passed tests but there was an improvement to hiss (for some equipment suffering from this) by putting in a better earth-ground.
This is better than most subjective listening as the issue was noise-hiss and easier to quantify-assess.
Live in the UK.
Anyway just providing an example where domestic mains should have zero effect on audio equipment.
Cheers
Orb
Yep something I have experienced myself with a building regulation electrician examining my mains.
I appreciate the importance of technical-reference ground, just showing an example of how the default installation was fine in theory and passed tests but there was an improvement to hiss (for some equipment suffering from this) by putting in a better earth-ground.
This is better than most subjective listening as the issue was noise-hiss and easier to quantify-assess.
Live in the UK.
Anyway just providing an example where domestic mains should have zero effect on audio equipment.
Cheers
Orb
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Another interesting aspect (especially Europe cannot comment about other regions) is that the design of the domestic mains causes it to act as an antenna and worringly as a transmitter.
This was covered by an electronics-science university lecturer for Hifi-News that also tied into a BBC research paper on such effects.
In practice this was also reported in 6moons when they decided to investigate noise on the mains and various solutions and why they may work:
Really interesting read can recommend it: http://www.6moons.com/audioreviews/bluehorizon/1.html
BTW they also investigate DC blocking and use of solution such as Isotek Syncro (not sure if it is mentioned in the above url but can be found easily if not).
Not suggesting this has anything to do with mains cables per se, but more food for thought.
I am curious though if mains cables can effect positively/negatively the behaviour of audio equipment in context of reference-technical ground, because technically mains cable shielding is academic when RFI is already within the domestic house-flat mains circuit due to its antenna behaviour.
Maybe though some designs help to "balance out" some noise related problems; such thoughts compounded by common or differential mode noise.
Will post another aspect that is interesting in a separate post.
Edit:
Here is the link for the DC blocking Isotek Syncro I mention above: http://www.6moons.com/audioreviews/isotek3/1.html
Isol-8 also has DC blocking in their products and some mains blocks.
Cheers
Orb
This was covered by an electronics-science university lecturer for Hifi-News that also tied into a BBC research paper on such effects.
In practice this was also reported in 6moons when they decided to investigate noise on the mains and various solutions and why they may work:
Really interesting read can recommend it: http://www.6moons.com/audioreviews/bluehorizon/1.html
BTW they also investigate DC blocking and use of solution such as Isotek Syncro (not sure if it is mentioned in the above url but can be found easily if not).
Not suggesting this has anything to do with mains cables per se, but more food for thought.
I am curious though if mains cables can effect positively/negatively the behaviour of audio equipment in context of reference-technical ground, because technically mains cable shielding is academic when RFI is already within the domestic house-flat mains circuit due to its antenna behaviour.
Maybe though some designs help to "balance out" some noise related problems; such thoughts compounded by common or differential mode noise.
Will post another aspect that is interesting in a separate post.
Edit:
Here is the link for the DC blocking Isotek Syncro I mention above: http://www.6moons.com/audioreviews/isotek3/1.html
Isol-8 also has DC blocking in their products and some mains blocks.
Cheers
Orb
@Gary, you might do a couple of experiments at the shop.
WARNING DON'T DO THIS ON an AC POWER CIRCUIT !! this is a test bench project
a] You probably have a bench DC supply (low voltage, high current), a big electrolytic cap and a spare amplifier power transformer.
Hook the DC supply to the transformer primary and see what the values are, then add the cap. Really what we need is a DC offset generator (with out the high voltage fundamental.
b] If you have a 4 terminal Ohm meter, you might measure some of the power cords. I measured some of the IEC cords in my spares box and was surprised how poorly a few measured.
WARNING DON'T DO THIS ON an AC POWER CIRCUIT !! this is a test bench project
a] You probably have a bench DC supply (low voltage, high current), a big electrolytic cap and a spare amplifier power transformer.
Hook the DC supply to the transformer primary and see what the values are, then add the cap. Really what we need is a DC offset generator (with out the high voltage fundamental.
b] If you have a 4 terminal Ohm meter, you might measure some of the power cords. I measured some of the IEC cords in my spares box and was surprised how poorly a few measured.
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One point that is seldom touched on is that, all cables act as interference antennas. That includes: power, interconnect and speaker cables. In the case of power cables, they are both transmitting and receiving antennas! So with interference antennas, changing the cable length or construction style (twist or shield) or placement/routing, will change the effectiveness of the interference antenna.
I'd like to understand it too. I've chased down and eliminated buzz within a system. Without pretty serious knowledge that I don't have, it was a trial and error process in which I tried different outlets, different circuits, different paths for different components, etc. That implies, I think, that we'd need a detailed diagram of mep's system and a detailed report on everything that was changed/re-routed/upgraded/filtered, etc. leading up to the elimination of the buzz to have any chance of isolating the cause of that happy accident. Does that seem fair? And if, with all that data in hand, we could isolate the improvement to the power cord, then would we not need to understand the source specific characteristics of this filtering capability in this power cord?
As usual, this is just logic; I'm not an engineer. I hope to learn something from this as well. But that cord is the first "component" in the system south of the electrical grid. Would it not follow that any noise it is capable of affecting would be coming from the grid, from outside the system itself, and that the capabilty to filter such noise would have to be engineered into the cord and wouldn't just happen because it was better wire. In fact, wouldn't better wire just conduct the noise into the system "better."
I'm probably missing something.
Tim
Speaking of antanae, I live in RFI hell. There's a total of 11 transmission towers with 2 miles of my home and I prefer LOMC carts. Get the picture?
It's relatively easy to test the susceptibility of most wire and even do A/B comparisons (I have a CDR recorder). For example, some cords on the phono stage PSU really do seem to reduce the noise.
A solid system foundation starting with a good AC power cord absolutely made a significant improvement in my audio system
I found this article http://www.gcaudio.com/resources/howtos/powercords.html that explains why the power cable is important component for anyone interested in reading it.
This article http://www.nordost.com/default/downloads/FoundationTheory.pdf explains why a solid system foundation makes sense for anyone interested in reading it.
I found this article http://www.gcaudio.com/resources/howtos/powercords.html that explains why the power cable is important component for anyone interested in reading it.
This article http://www.nordost.com/default/downloads/FoundationTheory.pdf explains why a solid system foundation makes sense for anyone interested in reading it.
The part in bold from my previous post is important:
DonH50 said:
A thorough discussion of grounding and shielding is well beyond the scope of this thread, and in fact there are plenty of classes and texts about the subject. My understanding is probably far above that of most audiophiles and yet well below the real RFI/EMI/EMC experts in the field.
Even back-to-back electrolytic caps make me nervous in an application like that; last time I did such a thing I used a special non-polar power capacitor designed for generator and power-line applications. That was many, many years ago so I don't recall the manufacturer.
The diode bridge is not actually used as a bridge; it is actually set up as a two pairs of series diodes, one going one way, one the other, to provide a safety path and clamp across the caps.
Adding anything like that will probably not pass UL muster... One reason I went with the capacitor I did was because it was used by the power company.
There are companies that make DC blocks and/or include them in their power conditioners.
How big a problem is DC on the power lines? I do not know but am curious. Some marketing would have you believe every other person suffers from it and it is destroying all the stuff in our homes; the power companies usually say there's nothing to worry about, transformers used in all power distribution networks eliminate any DC.
The diode bridge is not actually used as a bridge; it is actually set up as a two pairs of series diodes, one going one way, one the other, to provide a safety path and clamp across the caps.
Adding anything like that will probably not pass UL muster... One reason I went with the capacitor I did was because it was used by the power company.
There are companies that make DC blocks and/or include them in their power conditioners.
How big a problem is DC on the power lines? I do not know but am curious. Some marketing would have you believe every other person suffers from it and it is destroying all the stuff in our homes; the power companies usually say there's nothing to worry about, transformers used in all power distribution networks eliminate any DC.
Done all that.
The single electrolytic cap on a power line is dangerous. You run the risk of letting out the "magic smoke". The way to build a proper DC blocker (after a design by Nelson Pass) is as follows:
C1 & C2 are big electrolytic caps. No need to be high voltage as the DC on the line should be no more than 1V. But you have to make sure that they are high quality so that a reverse voltage of 1/2V or more won't cause them to fail. I use 10,000uF 10V parts.
D1 is a 35A bridge. Diodes have a forward voltage. In the case of the one I'm using, each diode has a forward voltage of 1.1V, and so this set-up will block up to 2.2V of DC in the line.
However, how it affects the music quality of the system is another matter. It will eliminate transformer hum though
Gary,
Did you remember that this thread is about a Krell KSA250 humming transformer? Using this circuit with this amplifier can be very dangerous!
The currents involved, mainly at start up are very high, and an exploding 10000 microfarad capacitor can be a dangerous weapon. Also most electrolytic capacitors can not survive a longtime at 20 Amps current.
Thanks Tom, I appreciate the detailed answer. Is a "properly shielded and terminated power cord" the stuff of very expensive replacement mains cable or something you would expect to come with any high-end audio component?
Tim
Burmester manufactured a DC suppressing box with a meter - as far as I remember typical values were under 1V DC. It was however very effective reducing mechanical hum in some equipment. Toroidal transformers are said to be more sensitive to DC than EI transformers, as they usually have lower DC primary resistance and are operated at higher flux. Perhaps one the more significant benefits of using fancy power re-generators and balancing transformers is just suppressing the DC component of mains!
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