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

Nope!!!!  Never happened to me.  Over the years, every single time I've changed or upgraded a power cable, whether it be for an amp or any other component, I always heard some kind of change in their sound.  Sometime the change in sound was subtle, and sometime it was more pronounced.   

davetheoilguy  and    jpwarren58 :   Completely avoiding the issue of value and the ability to discern any differences between a stock cord and an upscale one  - I applaud your efforts to focus on what can make a difference vs. whether that difference is worth the cost and can be heard by the system owner on their system. EVERY cord and component will be affected by its interaction with the surrounding environment and every element in the signal chain - including relative positioning. 

Both Cables and tube grids are excellent antennae, and grids, like styli and tone arms, are wonderful emitters/receptors of microphonics as well.  Although every system will vary, the length, shielding and relative positioning of each system element will have an impact on the final sound quality to a greater or lesser degree.  In a crowded server room, ethernet cables are almost always as short as possible and well shielded for a good reason. The same should apply to any situation where there is a signal quality concern.  How much induced noise is tolerable depends on the system components and what is necessary to achieve the desired result - be it good sound or good data.  

My only suggestion is to optimize what each user has first, then look at what might make the most obvious improvement.  E.G. - when swapping out a cable, is it the same length?  An extra foot or so of wire will make minimal difference on ANY given cable, but what you do with that extra foot may make a lot of difference.  Is it now closer to another cable, cross one at a different angle, get routed on a different path, get coiled up at all, or sit nearer or further away from a component?  This will significantly affect coupling between various elements, and for folks who feel that putting their cables on a riser to minimize coupling to the materials in the floor, being closer or further from a massive transformer in some devices' power supply may be what makes a significant difference, and whether the change in location or the change in cable shielding made the most difference can be tough to quantify.  

Bottom line - experiment freely with what you have now and optimize that.  THEN go out and search for whatever tweaks you wish to indulge yourself with, thus giving those new goodies the best possible baseline to start from.  

Most folks on this forum know it may be sub-optimal to sit your turntable on top of one of your speakers, but how many will search for room and component resonances with a test tone sweep, a good mic and their headphones (or a persistent-trace 'scope) to find the several places that are the worst, but perhaps not obviously bad locations for that turntable?  Is this a tweak?  Certainly. But the results may be just as obvious and avoidable as having a power cord that would best be routed around the other side of the equipment rack.  No two systems / listening rooms will ever be the same, and the same applies to sets of ears.  The optimal result is what pleases you most within the time and cost budget you have at the moment.                   Then, as always, take time to enjoy the music! 

You're one of the few who are not dealing with expectation bias and realize there is no objective difference between power cables and I applaud you.

@roadcykler  , if you read the OP, he states that he did hear a difference when he replaced the power cord on his preamp.

What I am interested in is whether he heard a difference when he replaced his OEM power cord with the $500 power cord.

@coleyounger1896 

No, it was a serious post.

+1 Boxcarman hit the nail on the head. You can upgrade to any power cord you wish, but you need to get the best power to the cable that you can. I'm not going to discuss power conditioners, as that is not what I am referring to.

I used several power cables in the $300 to $700 range new and used, and heard subtle improvements. I found a thread here that was talking about dedicated lines, power receptacles, etc. I decided to try some of this to see if it was real or snake oil; anyways it couldn't hurt.

I had two dedicated lines installed for about $400, one for the power amps, and one for the signal components.....and that was more of an improvement than any cord I installed.

Then I tested and upgraded the power receptacles, and WOW now we're talking. There was an even bigger improvement. Not only that, but now I could hear the difference between cables and could decide which ones provided improvements.

I tried about 11 or 12 (can't remember exactly) power receptacles over several months from Furutech, Acme, Oyaide, Cardas, Leviton, Hubbell, PS Audio, and Synergistic Research. All made at least some improvement, and others provided great improvements. Here are some thoughts

The Acme receptacle which is heavy silver over high copper brass/cryo treated/CFC treated, is much better than any base or hospital grade I tried (and a couple of the audiophile models listed above)....and well worth the $55 each. Great option for those on a tight budget.

The cream of the crop (and what I currently have installed): Furutech GTX-D(G) gold plated, Furutech GTX-D(R) rhodium plated, and the Oyaide R1 (not the SWO-XX series). My personal favorites in my system are the Furutech GTX-(G) and the Oyaide R1, but I can see how the GTX-D(R) would be preferred by those looking for more detail that they have in spades.....too much in my system, but by some accounts the the rhodium need over 200 hours to break in.

The Furutechs and Oyaide are list price between $200 to $260, but I found the GTX-D(G) and R1 for about $130 on sale, and the GTX-D(R) for $170

Your mileage may vary, but for less than the cost of a new cable, pulling dedicated lines and upgrading the receptacles provided a very noticeable improvement. It also allows me to hear the differences in cables, that I couldn't before.