@jji666 I don't know anything about your system or you overall experience all things audiophile, so I'll just reply by referencing my own experience. I too have considered the "your system is not resolving enough" comments to be a potential rationalization for people that are operating in the placebo range. I've had a few upgrades that I believed that I could hear a difference with, but also recognized that outside of a direct comparison I'd never be able to consistently detect if the upgrade was in or out of the system. In these cases I feel that there's an element of placebo in play.
I have a few of standards for determining when one things truly sounds better than another. First, when a change in equipment leads me to compulsively listen to all of my favorites again because everything sounds new and different. Second, when I can point to multiple specific things that sound different to me. Third, when the lesser setup bugs me. An example of the third one was comparing my Pathos Classic One to my Krell S-300i. They were very close for me and I struggled to determine a favorite. Then I rolled in some Mullard tubes in the Pathos and after that listening to the Krell was never satisfying outside of being a power amplifier in my home theater setup where I do like the way it sounds.
I had not messed with cables until the last couple of months because I didn't consider that a cable could make a significant improvement (at least in my system). The Mullard tubes elevated my system to a point that I became curious about what might be possible. Adding some very budget W Audio power cords made another significant change in the sound and I considered it to be an improvement. I also felt that I was at a point where interconnects were worth exploring so I picked up some Audioquest Chicago cables and once again was pleasantly surprised. I'm now considering trying an Audioquest Cinnamon digital coax cable even though I'm more of a 1's and 0's type of guy on the digital side of things.
The question that I'll probably not take the time to answer is if the cables really would have made a significant difference to my ear prior to the Mullard tubes. The difference they made was truly significant.
I do believe that as a system becomes more resolving it is possible to hear things that less resolving systems simply cannot benefit from. The cables that I've upgraded to are still considered budget cables, but I don't plan to go down the infinite rabbit hole of better and better cables. I think that if they were good enough to make a clear improvement that I've significantly narrowed the gap for what is possible in my system and spending significantly more would have a much lower ROI.
