I'm in my mid 60s, and still enjoy the sound of vinyl (this might be important). For digital, I've standardized on 24-bit 96 kHz stored as flac, being convinced to take that step when I heard my first 24/96 file 12 years ago. The speed and storage penalties have gone since then, but I regularly perform listening tests, assisted by the better and unbiased ears of my daughter. One test sticks in my mind - an A-B comparison between the CD and DSD layers ripped from the same SACD. We both clearly and quickly heard more detail in a quiet, complex opening passage. (I commend that specific test - it may be that 2 layers had different mixes, but everything else is as equal as possible.) My personal conjecture is that higher bit-depth is key, but I can't prove it; higher fs I'm less sure of. I held off buying a CD player for a long time because of the tiring harshness - reconstruction filter artefacts? - jitter? Modern high res DACs have overcome those issues. Cables? I use Mogami (or van Damme) for interconnects and speaker cables because of their pro audio reputation. I'm very sceptical indeed about mains cables. For digital, I use lab quality 75 ohm test cables terminated with BNCs. I've tried USB filters and cannot tell a difference. Finally, it's really hard for me to see how an Ethernet cable can have an effect. Why? Well, put some music on, then unplug the network cable. Did the music carry on playing for quite a while (10s of seconds) from the buffer? This sums up my difficulty with the industry - there's not enough genuine exposition of technical reasons why you should invest.
