With a pass 350.8 vac sig mk2 pre, lumin t2 and martin logan clx art speakers and a few other pieces, my wife and I were pretty thrilled with our system and weren't sure how much of a difference to expect with the holo may kte. The seller (an electrical engineer with decades of DIY high End audio experience) even said to expect somewhere in between a subtle and an "in your face" dif, thus our expectations were low and figured we would just sell it for what we paid for it if there was really no significant discernible difference. Iactually felt a bit silly or guilty spending that much on a dac, but Holy cow were we wrong.
The difference was *remarkable and extraordinary.* In short: we thought vocals sounded outstanding and accurate and beautiful and full and Rich before so how could they sound any better? The answer is that they now sound *human* in a way that I/we didn't know they could. For the first time it sounds like sting or Adele or whoever is actually in the room... it feels like you can sense the shape of their head and which direction they're standing. My wife is a medical expert with a couple of degrees in speech therapy and pathology, and is a doctor of anatomy, plus has a degree in vocal performance and music and she sings opera.
Did I mention she knows a bit about the human voice? :)
Her mouth dropped and she started laughing and then began crying when she heard the system with the May. cried when she heard the deck. I had the same reason and even the outstanding and Science- focused Goldensound reviewer on YouTube mentioned literally getting weepy listening to it.
The placement of instruments is remarkable in ways I didn't know to expect. I can't speak highly enough about it and when they come out with a higher end dac I’ll absolutely consider upgrading to that one.