@mahgister @inna "But there is way more to upgrading and optimizing than just reaching smoothness."
I understand where you are coming from. When I first plugged in my cost-no-object DIY phono/pre, I wasn’t sure I liked it - where were the high frequencies? It was all too smooth and too easy to like - then I played some Chopin, and the piano on the system sounded a lot more like the piano upstairs. Vocalists sounded like people that I knew. I realized that I had been listening to more distortion than music.
My pursuit of smoothness is predicated on a certain basic level of equipment, like not a single electrolytic cap anywhere in the signal path. Even so, YMMV.