It sounds really good to me.
You've answered your own question.
If you are purely curious, start another thread: which $xxxx preamp is best with my system? Pick one of the 16-20 various recommendations you get there...any one will do...maybe even one that's repeated more than once. Look for a used one here on A'gon sold by someone with a good track record. Buy it. Try it in your system. If you don't like it, sell it here on A'gon for about what you bought it for. Go back to your thread and pick a different one to try - repeat until you either find the one that sounds even better than "really good", or stop when your curiosity is satisfied, and or when you realize that "really good" is, well... is actually really good.
My experience has been that preamps can make a significant difference. There are also significant differences in using a passive vs active pre, as well as in using the gain available on some players, or gain in the digital domain (don't even go there). Tube preamps may sound different to you than SS preamps, and or may work better within your system. Whether or not you actually hear the differences in your own system, with your own music, as many here have pointed out, is entirely your call. Plenty of input in the archives to read through as well.
