I've been listening to the jaysaudiolab channel on YouTube exclusively through my Samsung 4k tv via toslink to my big rig since he started. He plays enjoyable and resolute music. I've also watched/listened to countless other audio channels maybe almost 500-800 videos I'm guessing. The 2 outstanding channels IMO are jays and alphaaudio (the Dutch guys)
Yes I hear small differences between his many multitude of megabuck amps, preamps, speakers, dacs, cables, servers etc. But they were small and hard to decide which was really better, only different, EXCEPT on 2 occasions that was blind (not knowing what brand or price), until the reveal.
Jay demonstrating these 2 items took his rig to the next level to my ears and musical connection in 2 series of demos and were the most memorable/enjoyable and I could instantly tell they both served the music as it should be. So yes you can tell outstanding gear via YouTube but you have to slog through countless videos to find the real gems to aspire to, that are truly next or 2 levels up in the service of music.
OK I'll end the suspense and tell you the 2 *whoa, what?* series of videos they were.
1) His Magico S7s
2) His new line of relatively reasonably priced cable looms he just started representing but can't remember the brand, they're from a smaller European country if memory serves me right
BOTH OUTSTANDING and worth looking into IMHO.
YMMV..