I certainly have, personally, experienced the improvement power cords can make on amplifiers...how about their value on other items, such as preamps with external powersuppies, and phono preamps....I know better than to apply layperson logic, which doesn't always work in audio, but it would seem that items that draw less "juice" would be less prone to changes in power cords....thoughts welcomed, but experience more interesting to me.....thanks
I like where this is going, and look forward to @lostinseattle follow up on his testing...I credit the dedication to do and share this
"I have no objection to trying it for myself, And I will as soon as I get my listening room finished. and I will as soon as I get my listening room finished"

Awesome, let us know what you think 
@lostinseattle brings up a valid point, if one can hear a difference, then "what is being changed"?
Different cable type....poses different resistance to the signal.
The thousands of feet electricity goes through outside the home do so through certain conductors, and dielectric materials used by the power company. When it enters your home, the impedance changed when the current passes through YOUR power cord (whether lamp cord or boutique).....the impedance of YOUR power cord is different from that of the power company because it uses different materials.
The resistance characteristic a cable poses when getting a signal from A to B determines how a cable sound. Of course, there are some gray areas and unknown, but one cable sounding different from another is a fact and not something made up or imagined. There are tons of cables that sound so similar that our ears can not pick up the difference, but there are some that sound quite different from one another. I feel like I have an idea.