The first time I remember a shock like that was when I replaced the digital interconnect between my DAC and Transport of my CD player. After learning that analog cables made a difference, I was convinced that luckily that can’t happen with digital. But I was a scientist… so I should verify it.
I swapped in a aftermarket digital cable. Wow. It was like someone came in and swapped out the components with vastly better ones. I just sat there stunned. This was 1984. The difference was like night and day… nothing subtle. Darn… digital interconnects matter as well, or even more.