I'm getting close to 100 hours on mine. While there still be some more burn in, any additional improvements is just gravy at this point. In other words, it sounds really good!! I have the DSD on the whole time. I love having a one box simple solution like the Sony HAP Z1ES in my system.
Having owned several cd players and server/DAC combos, The Sony HAP Z1ES Level 2 Mod is the first source that I have had that is the best all around performer. It has been my experience that recording quality has a huge impact on sound. Since I have a lot of pop/rock recordings, and am a big fan of post punk and modern bands that play that genre, a lot of the recordings are thin and harsh/hard. Trying to play those on a high end system can be frustrating. Most of the server/DAC combo's I have tried are really good with good recordings and not so good with the others. With the Sony HAP Z1ES, the enjoyment of my system is not limited to just the good recordings. The thin and hard recordings don't sound spectacular, but they sure are a lot more enjoyable.
One thing I really value is smoothness, but I don't want to sacrifice, things like detail and extension either. With the Red Wine Level 2 mod, I am getting the best of both worlds. It is really helping the rest of my system show it's stuff. I have really nice gear (my opinion

) that is playing well together now. In addition to the smooth, listenable sound, I am getting a nice stage, air, space, and lively but not shouty sound. That is a lot of positive audiophile description terms for sure, but that aside, the biggest compliment I can give the Red Wine Audio Level 2 Mod is that it draws me into the music. When I sit down to listen, my mind is not wondering, I am engaged. That means a lot fun and enjoyment. I am smitten with the Sony HAP Z1ES level 2 mod. The neat thing is there is still the level 3 out there, there is still tube rolling. How good can it get? Congrats Vinnie, job well done!!!
System
Sony HAP Z1ES Red Wine Audio Level 2 Mod>>>Herron Audio VTSP 3A (RO2) preamp>>>Burmester 911 MKIII power amp>>>Elac FS 249 BE speakers.