No doubt about it. Everyone hears sound from electronics differently. It's the way you hear it. And like it. Just like the subtleties in wine. It may be red with meat etc. But each red wine tastes differently to each person. No question. I have been using A Rockville Tubehead headphone amp as well as a Sony personal audio system ZS RS 60BT , Loxjie PD20, Schitt Magni2 Uber, and a hand built (not by me!) battery powered cmoy Grado knock off amp. I agree that they all make the same headphones "sound coloration" a bit different.But that is to my ears only. I tend to like clean punchy sound most of the time. Until my ears get bored or tired of it. I then find the Rockville Tubehead relieves that stress. The Loxjie ( using SE) works good with my Grado's. I prefer the sound coloration of the Rockville between the 2 tube hybrids though. But so does the Sony and every other amp I use. "Works/ Sounds Good" is my impression only. All the amplifiers do their job admirably. ( I will say, any Sony equipment I have ever bought from a Dap, to a cd player, to headphones, to receivers, has outlasted anything else I have bought in reference to build quality and performance.) I use a Hidiz S8 (powerful), Dragonfly Black( not too shabby), Modi 2 uber( sterile/clinical), or the Sony internal Dac( clean ,crisp) and connect an Ipad to them to listen to HD streams. I find that Amazon HD works well/exciting. Spotify sounds like a CD. Apple Music sounds more bland. I play CD's and a flash drive with Alac files as well as FM radio when I use my Sony RS60BT. Or I connect the Ipad using a DAC to the input of the Sony and use the RS60BT it as an amp. Sony sounds pretty clean on my Grado's (multiple models. Sr 325 being the highest priced ) , Senn Momentum, Hd 518, or HD 600, Bose qc25's wired, Koss monitors, Marshall Monitors, AKG 204, Phillips PH9500. I can't go wrong. It's just what my ear feels like that day. Headphones are the most important component in the chain as far as I can tell. I have always tried to replicate my Macintosh big rig that took me many years to purchase. Piece by piece. With used components. I wanted the same clarity and punch in my headphone setup. It seems like newer headphone components are the way to go. Because there isn't much vintage in the portable headphone rig area. It is still evolving.