How can a person form an opinion on something that they have not experienced? It is then no longer an informed opinion, it is a wild guess.
Or it could be based on technical understanding, technical analysis, or (hopefully well trained) technical instinct.
While I always hold Roxy's opinions in high regard, in this case I must agree with Mapman, whose opinions I also always hold in high regard. An unequivocal, unqualified, absolute, all encompassing statement such as the one I have quoted is tantamount to saying that technically based opinions invariably have zero place in audiophile pursuits. I would disagree with that notion.
One does not have to jump out of an airplane at 10,000 feet without a parachute in order to be qualified to express the opinion that it is not a good idea. Similarly, those with sufficiently good technical backgrounds can SOMETIMES correctly make "a priori" judgments about issues that fall within their areas of expertise.
Furthermore, those who HAVE tried a particular product and express an opinion about it can often be presenting information that has no more value than a "wild guess," not necessarily because they are imagining things, but because they may be attributing the perceived difference to the wrong variable (which is very easy to do in audio, IMO), or because their lack of understanding of the technical aspects of what is going on may mean that their findings would be inapplicable to other systems and circumstances.
Now certainly science, engineering, and technical understanding have a long way to go before they can explain and predict everything about what we hear and how a product or tweak will perform. Any good circuit design engineer will tell you that some things, as a practical matter, can't be analyzed and are inherently unpredictable. So the question becomes where to draw the line between what may be remotely within the realm of possibility, even though it may be counter-intuitive and/or not fully explainable, and what definitely deserves a place in the Twilight Zones of audio. Obviously opinions will differ widely about where to draw that line. But it seems to me that where to draw that line with respect to any specific tweak can and often should be the subject of legitimate debate.
In this case, although I have not personally experimented with audiophile-oriented outlets, as I presume Schipo has not, my opinion nevertheless differs from his, and I do believe that differences and improvements can be realized in many cases via that kind of upgrade. Although I would expect that any such comparisons, if performed in a properly disciplined manner with possible extraneous variables being well controlled, and across a wide variety of components, would provide results that are component, system, room, listener, and recording dependent, and that are not strongly correlated with price.
But I respect his right to express his opinion, and I consider it, along with the claims of some of those who have upgraded their outlets, to warrant legitimate debate, not summary rejection.
IMO. Best regards,
-- Al