how can a line cord affect frequency response ?

It's unfortunate when responses become so emotional and even vicious. As an EE myself, I too lived for many years believing that power cables were minimal at best to not just provide an improvement, but demonstrate a difference between two models. And after trying various power cable models, mainly NBS, PS Audio and Electroglide, I still could hear very little difference compared to "stock" power cables with the Aesthetix Io/Callisto preamp, Manley Ref DAC and CAT JL-3 amps. If anything, these models stand out in their respective classes as having way over-engineered power supplies. The output transformer alone in one CAT JL-3 amp dwarfs the power supply in most power amps. And this has much to do with this amp being the most dynamic amp I have heard by quite a stretch.

The electronics masters who have contributed to this thread would conclude that I did not hear differences because the power supplies here were already engineered to respond or compensate for any differences brought on by different power cables. Such a conclusion would only be due to ignorance as I quickly learned for myself.

After being constantly nagged by two local audiophile buddies, one an architect and another a physician, who said I needed very much to try a power conditioner (PLC) and then follow this with further power cable trials, I took their advice. Was I not the electronics engineer here? What could an architect or physician know about the affects of these products that I could not know? Afterall, I went through all the circuit analysis, power transfer, control systems, amplifier design, etc., courses.

Well in a nutshell, I realized how right they were. With three dedicated circuits for the system, one for each amp and the third for the sources and preamp, at $2k, the Audio Magic PLC brought on more of a refinement in terms of noise reduction and vastly improved resolution that no other component change had ever done in my system. The only unfortunate circumstance about this experience was that I had not listened to these two people sooner.

Two months later they both came over with quite a load of power cables for a shootout in my system. The differences now between power cables were dramatic. I could see them looking at me and silently saying, "I told you so". This long-time closed-minded EE had experienced how significant power cables can affect some of the most impressively designed audio components in the business, and to take the system's performance to levels I had not known were possible with these products.

For me now, I could not care less if someone else out there can not hear a difference in such cables. Their results are due to any number of reasons. But their lack of hearing this only indicates that the cables make no difference in the context of their system. The bottom line is that there are differences and they are often not subtle. If you need to go back and forth over and over to try and hear a difference, then plain and simple, your incoming power is a mess or your system's resolution is just not there yet. And for such a case, put your money elsewhere and repeat the power cable trials every couple years or so. I did, and finally it paid off. Just putting a pair of Purist Dominus power cables on the CAT amps brought explosive dynamic contrasts compared to the other power cables I had here.

As for the response by Mrtennis, "but it can not be verified", oh yes it can. Perhaps not in your system can it be verified, but in the context of many others it certainly can be. So many people in this thread have already concluded the outcome without putting forth the effort to hear the possibilities in a highly resolving and dynamic system. I can relate to such an attitude as I lived it myself on the issue of power cables for many years.

We can believe what we want to believe. And we can preach all we want about what we know due to our experiences and education. But one thing I am very grateful for here on A'gon is the amount of knowledge and experience I have gained by others who were more open minded than I was.....and I was the ultimate beneficiary as they had nothing to gain other than witnessing my happiness from the changes.

Oh and one more thing - do power cables affect frequency response? Go drop a Purist Dominus power cable on your favorite power amp, or DAC or preamp for that matter, and make note of the bottom octave presence and control that was not there before.

John

Very well written post by Jmcgrogan2.

As for Albert influencing the rest of us to buy his gear, of yes, every time he upgrades, a number of us tail waggers sit there drooling and waiting for the hand-me-down table scraps. 8-) And Albert, did you notice the Wotans for sale? Or are you holding out on a pair of JL-2s or quad of JL-3's?

Metro04 - As an educated EE, I clearly do not have the experience today to begin a scientific or engineering investigation on the matter for which you so very much want definitive answers. But I am not sure we are there yet anyway.

As advanced as our semiconductor and software industries have become, they still fall very short of the ear/brain processing to analyze sounds and therefore music. How and where do we even start to develop processes and systems to identify those sonic attributes that the ear and brain immediately tell us what is the real piano, what is a close simulation or what does not come even close? It's not only frequency or phase response analysis. Music is not this simple to quantify. If Mrtennis or anybody else requires these answers to get confirmation that differences do/don't exist, I suspect he is going to be waiting a long time.

Some of the most brilliant engineers are working on the latest developments of digital systems. And the test equipment for these systems has to be even more precise. And yet, in the final analysis, when I hear digital music, as enjoyable as it can be, my brain immediately tells me something is very wrong. Do we have the ability today to measure and quantify this? And if not, how can we expect the industry to provide a solution sheet with all the answers to explain why I can hear that power cable A affects an amplifier differently than power cable B?

There are events when I can not hear differences between some cables in certain links of the chain; this is good news as it leaves money in my pocket. And when there are differences, the more expensive product is not always the one I prefer. Again, good news as it saved me the expense. But there are times when I discover a cable or any other component for that matter that brings on more abc or xyz; it gets me that much closer to the musical performance. It's a win situation in any of these cases.

If we go into the audition with a seeded mind that we will or will not hear a difference, we have to be prepared to accept that the outcome could be different. And this is independent of any survey, poll, testing, etc., done by any other person or group who have documented that cables in fact do or do not make a difference.

I am clearly no self-tauted audiophile. And I am not trying to provide unverified testimonials either. I simply shared my experience that this closed-minded enginner let his ears be the factor vs. a printed technical report to determine that such differences do or do not exist. If one person can hear that differences exist, then they do. And that person could very well be a third party.

As an engineer, I know how easy it is for data to be "presented" in a way that would cause anyone to initially come to any conclusion. And how many of us have access to the facilities to prove or disprove such claims? We rely on others to do this. So this too is all based on faith.

As Mrtennis reported, "hearing is believing, either i hear a difference or i don't hear a difference. at this point it's an anecdotal report which cannot be verified". But Mrtennis, as any of us who are just another citizen of the larger collective, reading a report is believing, and often neither you nor I can verify such. Thank you, but in the case of audio cable differences, I have more faith in my own ears.

John

Mrtennis essentially states that without proof, there is no knowledge, only opinion. But in the big picture, much of what we all personally consider knowledge is not proven until we too witness and experience if for ourselves.

I "know" that Canberra is the capital of Australia. But how do I really know that Australia even exists? I have not been there. Many people claim it is a continent in the southern hemisphere which I must take as faith. And since I have not witnessed its existence, is my "knowledge" of this indeed not knowledge? In my opinion, Australia exists but I do not know for sure. And even when my plane lands there, how do I still know I am in Australia? My weeklong trek across the Australian desert in a jeep may have in fact been through the California and Nevada deserts. Life is one huge box of faith.

What defines the line between opinion and knowledge and thus fact? Clearly we have a group here that continues to profess that we can not base our knowledge on what we hear. So what do we use to substantiate out claims? Our eyesight? If I alternate between power cables A and B, and repeatedly take measurements through various tests, compare the charts/plots etc., and can visually verify that cable A always has a higher peak than cable B and frequency X, and so on, then can I deduce from these efforts that I now have knowledge that there is truly a difference? But why do I only trust what my eyes tell me and not what my ears told me before? And if it is not a sight vs. sound issue, then it comes down to needing the test equipment to provide the basis for knowledge rather than my own senses.

As I tried to infer before, even when our senses tell us that differences exist, we may be a long ways off from identifying why they do exist. And as an engineer, I too want to know the how and why of everything around me. But this is simply not realistic.