reano, let me see if I can clarify. I am not trying to argue with you or offend you, but we seem to be two ships passing in the night. I offer the following:
1. As an initial matter, let's assume we are not talking about cables that measure differently to the extent that most would say the differences in the measured parameters should be audible.
2. I do not have proof (and I don't know of any proof) that cables sound different if by "proof" you mean scientific or other evidence that is of a nature and quantity such that all reasonably objective people would be or should be convinced of the fact beyond a reasonable doubt (let's assume that is the standard for discussion purposes).
3. There is "evidence" that cables sound different. Such evidence includes the reports of many who have listened to cables and report hearing differences. This may not be persuasive evidence to you or others, and it may not be evidence to establish beyond a reasonable doubt the existence of the fact (i.e., "proof"), but it is evidence.
4. I have evidence that cables sound different in my system. It is based on what I have heard. Is this "proof" to me? Yes, it is, to the extent that I am convinced of the fact and am willing to incur the cost of the cable for the amount of improvement I hear. In other words, the fact is established for me with sufficient proof for me to incur a cost or take an action. Is what I consider "proof" to me sufficient proof for bigshot, mihm5, etc.? No. Is this "proof" of a nature and quantity that all reasonably objective people would be convinced of the fact? No. Will it be proof to you? I don't see how it could be, since what you hear in your system might be entirely different.
5. The fact that there is not proof beyond a reasonable doubt such that all reasonably objective people would be or should be convinced of the fact is something that I suspect you are fully aware of. Therefore, asking the question "is there proof," seems to be designed to start an argument. But perhaps we have not been fair to you and need to give you the benefit of the doubt. Therefore, the answer to the question, again, IMO is that there is no proof such that all reasonably objective people would be or should be convinced of the fact beyond a reasonable doubt.
6. The fact that there is currently no "proof" does not mean that the differences do not exist, as you know. Nor does it mean that there might eventually be proof. But if you are looking for proof at this time -- as I have defined it -- I don't think it exists.
Hope this helps clarify my points and advances the discussion.