Given the differences are claimed to *audible*, I guess it’s reasonable to assume that sth like noise levels, sound distortions etc must show measureable differences after changing power cord. Curious whether anyone has done that.
@yang_hong
Transient signals are non-repetitive and difficult to measure without constructing sophisticated test signals. We can attempt to measure a broad spectrum of "noise" in a system which should be ideally silent. Even when visible, it may be difficult to correlate how the signal correlated noise will interact with the signal and manifest itself audibly.
I often hear the improvements as a broadening of the stereo presentation or as an increase in the harmonic richness such as is apparent in the sounding board of a piano.
In the end, if it doesn’t give you pleasure to strive for and realize these improvements then don’t worry about it. Competent interconnection is all that’s needed. As I mentioned in my original entry, some folks feel like they understand the world when they obtain a little knowledge and find it unsettling when others express ideas which suggest that their understanding may not be complete. This doesn’t mean that those who believe they hear differences aren’t themselves riddled with biases, usually of the sort that whatever they have is the best or all that is needed by anyone. This isn’t limited to audio. ;)