Rja, these are facts stated about outlets, not just beliefs. As I stated, I never have seen anything, that supports an outlet having any sound characteristic. Show me proof, if you believe otherwise.
This comes from engineers, and other knowledgeable people, that help make audio reproduction as we know it happen. Also other electronic based products, that even helps make our world better, and life easier. Same electronics behind that too. Based on facts.
Get to know some engineers. Study some electronics, and learn how these things work. If you did, it may help you understand some statements others make. Then when you've built amps, power supplies, even just for an amateur hobby, you'll find out how different parts in them, the voltage supplying them, can influence their different sound. Or just modify some. That helps make some statements made, more than just what we believe. It helps bring the facts out.