Well, to be honest, stock. Except I did get another power supply for it. Perhaps my expectations were just too high for this unit. Even stock there was much hype when it first started making press waves. At the time I had a Bel Canto Dac-1, a Jolida JD-100 that I had recently purchased and, a dcs Elgar/Purcell rig (my main rig). Against the Bel Canto and Jolida the Art was a disappointment. Dynamics were reasonable but, the general sound character was bland, lacking depth and emotion, and with a certain tinny (hi-fi'ish) sound in the treble area. It just was not my cup of tea. All three dacs paled in comparison to the dcs rig which remains my reference.
Perhaps when modified the Art takes on a whole new character and sonic perspective. I thought about getting mine modified but, only one place was offering a mod at the time and, the cost was going to start increasing to the point of being competitive with the Jolida which was already making imminently musical tunes in my house. Therefore I saw no reason to spend more money on it. I purchased the Art DI/O based on the hype at the time which proclaimed it to be a killer dac at a dirt cheap price. Dirt cheap it was, killer it wasn't.
For those with the patience and wherewithall to get the Art modified and tweaked, I am glad it worked out for you.
