So I have been listening to this album for the past week basically on repeat with the X9. Today I decided to switch to the Topping DX5II and I think if my ears are not deceiving me, there is a little more zinc at the vocals/top end.
Would fit with my obversations, assuming by "zinc" you mean a bit more clarity or pizazz. Although not listened to the Topping, but have heard an ESS DAC compared to the X9s AKM. Would also fit the broad consensus, well, apart from the DaCs mAkE No DiffERence crowd.
Sabre ESS DACs are thought to be more resolving, I found them to be slightly brighter
The X9s AKM DAC, is more rounded tonally - perhaps with less upper resolution
The differences were so slight, that I wasn't sure they existed. Although comparing to the K11 r2r, that DAC was less resolving in the treble, and had way less control of bass, along with a closer soundstage - although it's treatment of mids and voices was lovely. Since I also have a Mojo 2, it is a little brighter than the AKM, and not as resolving as the ESS. Overall, I've begun to prefer the X9, but it's mostly what I've been listening to, so it's most likely familiarity, rather than any real preference. Considering switching to the Mojo for a little bit, see if it will swing back the other way. I think it will. After extended usage I'm thinking the AKM is the slight better of these 2, but it's really close, and perceptual differences in the tonality, particularly in the trebble, can sound like extra resolution and detail. There's more differences in sources, and output devices. As well as EQ. Since the Mojo only has a 4 band EQ system, and it's fairly basic, I might actually be hitting the end of my time with it.
Ears and minds decieve though, so the only difference I'd be confident in spotting in the above is the K11 r2r.