New expensive power cord for amp and no change in sound?

I’m with invalid. In my experience, a last 5ft power cord is much more important than in-wall wiring. Like a garden water hose, the nozzle only sees what it’s connected.

I am not arguing about electricity because I don't know much about that subject, but as far as water coming out of a garden hose to a nozzle, if all the plumbing in the house is ancient and gunked up, it will have a detrimental effect on the water pressure at the nozzle connected to the garden hose.  I can tell you that from experience.

@roxy54 I have a 250.8 and an ARC REF 6.  I noticed a significant audible difference going from stock ARC to a Shunyata Alpha v2.  On the other hand, the difference between the Pass stock cord and another Shunyata was audibly better, but not nearly as significant as on the ARC.  But as they say, “everything matters.” So speakers, DAC, other cables all have some effect on how each component sounds.  I used an Audience Au24 on the Pass and then put in a Shunyata and honestly didn’t hear much of a difference.  But I was going for a full Shunyata loom, so I was ok with what seemed to be a minor improvment.

@mihorn Your comment “In my experience, a last 5ft power cord is much more important than in-wall wiring. Like a garden water hose, the nozzle only sees what it’s connected. The audio equipment draws the current from a power cord which is a bigger reservoir than in-wall wiring.” defies all logic and physics. 

You seriously think that your “high-end” 5 foot long power cord is a “reservoir” for energy/electrons/electricity?

😂 

This phenomena is known as the “real world.” Welcome. 

When I moved to my current house I had the electrical service completely overhauled with new main panel, and discrete lines for my main stereo system, and hospital grade receptacles.  I then did some testing with a couple of others present, using regular power cords, some borrowed 'high end' expensive cords and some that I had made up myself using heavier than normal cable.

The results were interesting and saved me a whack of money - my home made ones were judged the equal of the audiophile super expensive cables in blind listening tests.  The high end cables went back and I have been happy with the home made ever since.  Had I not arranged for three of us to listen, I might have fallen for the usual "they cost a lot so they must sound better" myth of the high end stuff.  Not saying that can't sometimes be the case, just that high cost and a fancy brand name guarantees you nothing.

I think that many purchases of things like that are later justified by people who think that if they don't sound better then they - the buyers- are idiots and of course that could never be the case, so....they mentally qualify what they are hearing..