Why do I need power management if I have a great power cord?

It‘s not a question of removing audible hum hiss and noise. I have no such issues yet have garnered definite audible improvements with the use of a PS Audio P10 and an industrial 1KW isolation transformer (used individually) upstream on certain system components.

@ghdprentice "High end audio is a very complex endeavor… full of ambiguity and complexity."

Well said. The problem is not "trying to prove a negative," as someone else said, the problem is to hear something that one does not yet know how to hear. Hearing is mostly interpretation and only partly physical. One needs to know what to listen for.

I think of the days before OLED TV’s. People would say, "This IS a black background." Then, much blacker blacks came along and people could now see that they had been missing something. And it was not just the blacks. It was everything on the screen. Everything gets better -- and the whole experience gets better.

So, the first reaction -- "This is just 'up-selling' or 'snake oil' -- turns out to be wrong. What folks came to learn was that quieting visual noise (making backgrounds blacker) changes the foreground by changing the background. That is very hard for people to understand, because they are focused -- almost exclusively -- on what is in the foreground. The fundamental mistake they make is to disconnect foreground and background. They are entangled for both perception and conception. @mahgister makes this point very well when he tries to direct attention to the room's acoustics. But his point applies very well to the technological devices' designs and their power sources, too.

This point about the "blacker background" applies pari passu to other things besides background noise; the way highs, mids, bass registers are expressed by speakers, the way transients and dynamics are shaped. And the technologies that make all these areas better are often not easy to grok, which is why your suggestions of resources like Robert Harley is so appropriate.

It‘s not a question of removing audible hum hiss and noise. I have no such issues yet have garnered definite audible improvements with the use of a PS Audio P10 and an industrial 1KW isolation transformer (used individually) upstream on certain system components.

• Which “industrial 1KW isolation transformer”
• Which “certain system components”

Why do I need clean water if I have good quality copper pipes?

until your shiny copper builds up a mineral residue you are probably better off drinking bottled water

no idea of the brand of industrial transformer, I got it cheap off the trade classifieds. It‘s a big ugly mutha.

system components - all digital, preamps, and some integrateds and a few power amps. I have lot so please don‘t ask me to start listing

for what I paid for it the transformer is brilliant on digital