Within the context of my digital music playback system, which involves using Roon to stream Tidal and Qobuz, and to play stored music files, my hierarchy of differences I hear is:
- Server/Roon core: almost no differences heard between servers
- Fiber optic vs. Ethernet: little to subtle sonic differences at most, but not reliably discerned
- Switches, on-line tweaks, and decrapifiers: no reliably heard differences
- Streamer/Roon endpoint: more substantial sonic differences and the ability for some streamers to significantly improve sound quality
- DDC: Little to subtle sonic differences noted, at most
- Digital cables including USB: small differences between coax, AES/EBU, and USB, but very little to no differences between different cables of the same type
- DAC: Each displays its own sonic flavor and can sound substantially different from each other
In summary, I have noted differences in the sound of streamers and DACs, but not much with anything else in the digital chain.