I tried out the SuperSocket from Russ Andrews with the intention of proving that it did not or could not work as claimed. I was wrong. It does work as claimed.
As I've said repeatedly (no idea why you can't grasp it) all your findings are irrelevant because you did not conduct the tests in a suitable manner - you cannot rule out expectation, physiological effects and other things making it impossible for you to make a fair comparison.
As there is no (that I know of) conceivable mechanism by which replacing a working mains socket with a different working mains socket could have a significant effect on the sound of a hifi system connected to that socket I am inclined to think - in the absence of good solid evidence against - that your findings are unreliable.