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

There are amps that are not reacting to any power cord switching  , regardless of the price. I have couple of amps that did this to me.Though that was 20 yrs ago.Maybe my listening skills is not yet there to figure out the change.

@immatthewj To me that bumps up against the problem of why does different have to cost so much.  I understand people like to switch tubes and compare.  When it turns into you need to try this simple mechanical device that just happens to cost $4,000 I lose interest.  It feels too much like exploiting OCD, which we all have at least a little.

@jon_5912  , I guess it all comes down to what you get for your 4k and whether or not what you get is worth 4k to you.  In this case, I think OP is saying he cannot hear ANY difference between $500 and "several k.".  But perhaps in other applications the consumer might hear a difference.  You asked why the manufacturers are not putting high dollar cords on their stuff that they send out if it makes a difference, and I simply think that they do not want to raise the msrp that much on an upgrade that not everyone thinks is important and wants to pay a lot for.

A few thoughts:

1. Can you return it?
2. Is it the same cord as on your preamp?  Have you swapped cords on the pre-amp and amp as an experiment
3. I don't view it as you threw money away if you are enjoying music and the process.  If you can't return it, perhaps you can sell it or even let a friend experiment to gauge their experience.  (I'm making the assumption, you are disappointed but still have a lot of things to be grateful for!)

Without the components and names of the power cords involved this is not a useful thread. I can’t imagine a thread being deleted by naming the components involved. That is the basic function of this forum.