08-15-11: Lissnr
There are 2 widely disparate "camps" about whether power cords can make a noticeable change in the sound of your system (assuming adequate gauges/capacity for the accompanying component) .... I would submit that there is a third camp, to which I happen to belong. That camp believes as follows: 1)There are sonic differences between power cords, for reasons that are technically explainable (e.g., shielding, resistance, perhaps inductance), and probably for reasons that are not technically explainable. 2)The differences reflect interactions between power cord characteristics, the characteristics of the particular incoming AC, and the particular components in the particular system, especially their power supplies. 3)There is no reason to expect much if any consistency of those interactions from system to system, and therefore no reason to expect much if any consistency or predictability of the sonic effects of a particular power cord. 4)While a power cord may have effects on the tonality of any given system, it is incorrect to attribute tonal characteristics to a power cord, because those tonal effects will vary from system to system. 5)Given a reasonably good system, the ability of a system to resolve musical detail, and its ability to resolve differences between power cords, are two different things. Which may sometimes, in fact, have an inverse relationship. An ideal power supply, were it to exist, would have no sensitivity to the quality of the incoming AC, and would send no rfi or other spurii back into the power cord, from where it could couple into other parts of the system. 6)Given the foregoing, there is no reason to expect a high degree of correlation between power cord performance and power cord price. Regards, -- Al |
Hi Mr. T,
Let me make clear that my comments pertained strictly to power cords, not to interconnect cables, speaker cables, or phono cables. In those cases, IMO, it is certainly conceivable, and even expectable, that consistent results (differing in degree, but not in kind) would occur across multiple systems.
Foster_9 & Kijanki, thanks very much for your kind words.
Best regards,
-- Al |
Wonderful comment and insight, Bryon. I could not be in more complete agreement.
Another example that provides a good illustration of what you are referring to would be digital cables. Certainly different digital cables can produce different sonic results in a given system. But those differences will be the result of a complex set of interactions between their characteristics, such as impedance accuracy, shield resistance, shield quality, propagation velocity, the particular length that is used, etc., and the characteristics of the components that the cable is connecting, such as impedance accuracy, signal risetimes and falltimes, ground loop susceptibility, jitter rejection capability, etc. Once again resulting in there being little likelihood of a given cable having similar sonic effects across different systems, a point that seems to be commonly under-recognized.
Thanks! Best regards,
-- Al |
Hi Zaikesman,
Lets take some specific examples, relevant to power cords:
1)Power cords will differ somewhat in terms of resistance. That will result in differences in the ac voltages that appear at the power connectors of the components to which they are connected. The voltage differences will vary depending on the current draw of the components, as well as on the resistance of the cords. Ill ignore the fact that those voItage differences may be overshadowed by fluctuations in the incoming line voltage that may occur from time to time, and from location to location. Is it expectable that the power cord-related voltage differences may be sonically significant? Certainly. Is it expectable that the resulting sonic differences among various components will be consistent and predictable?
I submit that experience and experimentation are irrelevant to the conclusion that the answer to that specific question is no. I say that as someone with multiple decades of experience designing advanced analog and digital circuits (not for audio). It would depend on how tightly regulated the power supplies of the components are, on the types of component parts that are used throughout the design, on the circuit topology that is used, on the thermal management provisions in the design, and on literally countless other component-dependent technical variables.
2)Power cords will differ somewhat in terms of shielding effectiveness. That will result in differences in the amount of rfi and noise that is presented to the power input of the connected component, as well as the amount of rfi and noise that is generated within that component that may couple from the power cord to other nearby components.
Is it expectable that those rfi and noise effects may have sonic consequences? Certainly. Is it expectable that those consequences will be consistent and predictable across different components, different systems, different physical arrangements of those components, and different interconnection configurations between those components? No way. Experience and experimentation are not necessary to reach that conclusion.
3)Power cords will differ in terms of inductance, which may, particularly in the case of power amplifiers, limit the speed with which abrupt changes in current demands can be responded to. Ill ignore the fact that the Romex in the walls will probably impose limitations in that response that are much more significant. Given that, is it conceivable that those differences will have sonic consequences? Certainly. Is it expectable that those sonic consequences will be consistent among Class A designs, whose current draw variations are relatively small, Class D designs where those variations are very large, and Class AB designs that fall at various points in between? Not to mention that within each design class there are innumerable other relevant variables, such as energy storage provisions. Once again, I would assert that experience and experimentation are irrelevant to the conclusion that the answer is no.
I respect the sincerity of your conclusions, and your experience-based observations. I am one who tries to keep an open mind about such matters, BUT WITHIN FINITE LIMITS. I define those limits based on reasonableness, common sense, and my technical understanding of how things work.
I would add that performing a truly meaningful comparison of a multitude of power cords, encompassing a multitude of different components and systems, while carefully identifying and controlling extraneous variables, both technical ones and psychological ones, is a formidable task that would be impracticable for most audiophiles. I have certainly not attempted to do that. I recognize that there are some who would claim to have done that, and to have reached conclusions similar to yours. But with all due respect, I remain skeptical. (And I repeat, that skepticism is not about the existence of differences, but about their consistency and predictability from system to system, and about the degree of correlation between cost and performance).
If you or anyone else can cite additional technical factors beyond the three I mentioned above, that might account for why power cords may make differences that can be expected to be consistent and predictable across multiple component and system configurations, and that rise above the level of speculation or marketing pseudo-science, I would be happy to consider them and comment further.
Regards,
-- Al |
I first want to second the comments by Dave (Corazon) about the quality and value of many of the posts in this thread. While it is of course not expectable that a clear consensus will be reached, or that many minds will be changed by the debate, it seems clear that more than a few of the posts above are potentially of uncommonly high value, to both protagonists and readers, compared to those that typically appear in threads devoted to cables, and especially to power cords. If only by virtue of stimulating and broadening each persons thinking. A question for Doug: In your several references to the value of testing with complete sets of cables from the same manufacturer, are you referring to complete sets of just power cords, or to sets comprising power cords, speaker cables, line-level interconnects, and perhaps also phono cables. If the latter, then I not only find your arguments to be technically plausible, but even expectable. As I indicated in a post earlier in this thread, IMO extrinisic technical factors relating to cables which conduct analog signals can easily explain the existence of sonic signatures, that will be consistent and predictable across multiple components and systems, obviously not in degree, but in kind. Some examples: Speaker cables having low inductance will, everything else being equal, provide increased high frequency extension, to a greater or lesser degree depending on the speakers impedance at high frequencies. Lesser degree, of course, will include some cases in which the effect is audibly insignificant, especially if the cable is short. Interconnect cables having low capacitance will do the same, to a greater or lesser degree depending on the output impedance of the component driving the cable. Unbalanced interconnect cables having low resistance in their shield or other return conductor will reduce ground loop-related hum and/or high frequency noise that may tend to occur with electronic components in some setups, thereby improving background blackness and resolution of low level detail. On the other hand, if your reference to complete sets refers to just power cords, then while I think your comments support your case much more persuasively than most others that tend to be encountered in threads dealing with this subject matter, and although I obviously am not in a position to question or doubt your extensive relevant listening experience, and although I certainly do not believe that generally recognized technical principles can come close to explaining all of our sonic perceptions, the combination of lack of convincing technical rationale which is inherent in that position, and what I perceive to be the major degree of technical counter-intuitiveness of that position, still leaves me skeptical (concerning consistency and predictability across multiple systems, as well as price/performance correlation, not concerning the existence of differences!). Also, it should be kept in mind that comparison of multiple complete sets of power cords in a given system, at a given location, does not provide data points relevant to proving consistency or predictability of the effects of those cords across differing ac line conditions, including differences in line voltages, line noise, and line distortion conditions that are likely to be encountered at differing locations. 08-20-11: Zaikesman
though I did wonder why you omitted capacitance -- I'm sure you have a reason and will explain it I didnt mention capacitance because I would not expect its effects to be quantitatively significant in a power cord application. Even if they were, I would expect those effects to only occur at very high rf frequencies, causing them to be, once again, unpredictable, inconsistent, and system and setup dependent. Best regards, -- Al |
Zaikesman -- I suspect that you would have been thorough enough to do this, but just to be sure, did you repeat your power cord comparisons after you obtained the footers, to verify that similar differences resulted with the various power cords you used when the unit was right side up, compared to when it was upside down?
Obviously the preamp was not designed, developed, tested, and voiced with the expectation that it would be used in an upside down position. I can certainly envision that operating a component upside down would have sonic consequences, due to the thermal differences that would result throughout its circuitry, those effects conceivably including increased sensitivity to variations in power-related parameters such as ac voltage.
Regards,
-- Al |
When and if Liguy performs his power cord test I hope that he will utilize better methodology than in the biwire comparison that is described in the paragraph quoted by Doug. Note that the jaw-dropping difference Liguy found, and attributed to biwiring, was between the performance of the speakers when biwired into his own system in his own room, vs. their performance when single-wired into the dealer's system in the dealer's room. This was pointed out by several people in the original thread, and only addressed by him experimentally near the end of the thread: I have, at the prodding of many of you who have posted in this thread, tried putting the jumpers back in and just connecting one set of wires. So here is the verdict. It still sounds great! But not as good as with the speakers fully Biwired. Even though the Martin Logans are not known for their bass, the bass is much, much tighter with the speakers biwired. I have referred many times in discussions of power cords and various tweaks to how easy it is to be unaware of and fail to control extraneous variables, resulting in misleading or erroneous conclusions. If an EE and skeptic such as Liguy can make such a fundamental error, perhaps I've under-estimated how pervasive an issue that tends to be. Regards, -- Al |
11-17-12: Tbg
But it is not a science; it is a consumer's decision about purchases. If Liguy is satisfied, that is it. So you do not see anything objectionable about promulgating a conclusion about biwiring to the rest of the world, via an Internet forum, based on a comparison in two completely different rooms between two systems that were completely different aside from the speakers? Whether or not the poster was satisfied is irrelevant. The issue is that others may be induced to direct their investments of time and money based on conclusions that were reached via methodology that is fundamentally flawed. Regards, -- Al |
Well, it seems that contrary to the old saying, great minds don't necessarily think alike :-)
In this case, while Richard gives an emphatic second to the comment by Tbg, I'll give an emphatic second to the ones from Knghifi and Doug Schroeder.
Best regards,
-- Al |
Tbg & Richard, why are we all here? Most fundamentally, as I see it, and as I believe most of us see it, we are here to share information, ideas, and experiences, which hopefully will be mutually beneficial as we try to guide our investments of time and money in directions that stand the greatest chance of being rewarding.
When someone starts a thread proclaiming that "I am stunned .... I can finally say that I am a skeptic no longer with respect to biwiring," and it is only upon VERY careful reading of the post that it becomes apparent that this conclusion was reached by comparing a biwired connection of a speaker in his room, with his system, vs. a single wired connection of that speaker in a dealer's showroom, with a completely different system, shouldn't that statement be challenged?
And if, as you say, all that matters is that the poster is satisfied, what is the point to his post, and indeed to the forum itself?
Frankly, and with all due respect, I am dumbfounded at your positions on this issue.
Regards,
-- Al |
