Think Audio Research, Conrad Johnson, VAC, and Cary. These are in the order I would consider them.
There are layers of what constitutes great sound (balance, details, bass, micro-details, noice floor, rhythm and pace, etc.). Companies like those above have been at the forefront of understanding sound and building equipment to capture it for a very long time. It takes a long time to move from what you think of as great sound as a novice audiophile to really knowing… these companies have worked at achieving this for many decades.
For the last couple years I have owned top of the line reference components from Audio Research (see my system under user ID) although I have pursued the high end for 50 years, I continually discover how these components capture the essence of music naturally, proportionately at all levels, in ways that I did not understand before. I was too easily lured by details and slam… which actually lured me away from really musical enjoyment. Don’t get me wrong, my system reveals all the details of any system I have owned or heard, but it shows them off in a truly natural way… just like live acoustical music, not bringing the details out in front and artificially sticking them in your face.
There are many companies that give people what they think they want… up front details and slam… slap you in the fact. But the companies I listen above work at a higher level. Creating real musical experiences. I get it now. I saw well healed old guys buying ARC stuff when I was young an poor. They were wise. This stuff is amazing.
Truly great audiophile gear goes beyond just “wow, that sounds great”. They are like refined instruments allowing to learn and evolve and explore deeper meaning in the music you are listening to.