How are you hearing no difference?

Act chew ally the cupped hands improves dynamic range, especially for systems that lack dynamic range, and loudness, i.e., a better antenna, but the down side is it impacts soundstage. Once your system can perform dynamically, e.g., room acoustics treatments, you’ll discover the cupped hands doesn’t do much at all. Recordings are made with human ears in mind, not Mr. Spock’s. You’re not hearing the rear reflections since the hands block them.

In fact, in the case of power amplifiers as an example; it needs to accurately amplify the input signal, and transfer that signal, fully intact, to a low impedance load.
A well-designed power amplifier, in theory, is not supposed to reshape the input in any unintended or involuntary manner, so I support the concept that accuracy improves when the potential for error and distortion is minimized. 

Hence there are indeed, subjective differences in DAC,s and particularly pre/ power amps - however: much depends on how they integrate with the speaker load and the components having low errors and distortion.
see: https://www.thesoundadvocate.com/2018/10/the-role-of-power-amplifiers-today/

Unfortunately, there are many people who’ve never been taught how to listen or what to listen for and that’s because they’ve never met a person, or found a dealer/store, who was willing or able to teach them.  Can you tell the difference between a male and female voice?  Congratulations, you can hear.  If you go to a Hifi shop to listen with the preconceived notion you won’t hear any differences, then there’s a great chance you won’t.  The teacher has to be willing to teach, but the student also has to be willing to learn...  

Bingo! 

I need a psychologist to weigh in here. (I am not one). The central fallacy as I see it is; assuming one can hear a difference in presentation between two similar components, is one better? Chocolate and vanilla are both ice creams, both cold and sweet, but decidedly different; so which is "better"? Can't they just be different? I prefer vanilla, so to ME it is "better."
This is the tyrrany of choice; we assume that because two things are demonstrably different one has to be better. Take tubes and transistors. They both distort, but in different ways. This is what gives them their characteristic "sounds." But as they improve in quality their distortions minimize and their sounds become more similar. Still, each has a distinctive "sound" of its own; perhaps a vanishingly small difference but since there are two different pieces being compared then at least a theoretical difference. Which is better? The one I prefer may not be what you prefer, but for me the better component is the one I prefer, and I don't really care what YOU like best. 
I find audiophiles divide into two groups; those that listen to music with components vs. those that listen to components with music.