Just got the ST-10/10H and am checking 'em out!
I swapped my newly arrived ST-10 for my tweaked N-Core NC-400 for starters. I'm powering my Von Schweikert VR-5 HSE, a 91 db/m sensitive 4 ohm design. First up, I'm using my NAD M51 DAC as source, w/ Zenwave D4 balanced ICs.
I'm very pleased with the sound. There are clearly differences in sonics- the N-Core has a more forward top end- it pushes the detail a bit more. The ST-10 has a more relaxed sound overall, with a detailed yet easy top end. Detail is very close; the N-core might have a small edge, with a bit more air on top, but the more forward upper range could be responsible for that. The bottom end of the ST-10 is similarly deep and powerful, but I give it the edge in control, which is remarkable as the N-core is the best I've had in that area.
The overall impression of the amp is very enjoyable- it lets the sonic fabric through with a very natural sounding soundstage. Very nice indeed. Certainly in the same class as the N-Core, but with a different, more relaxed flavor.
I just moved the 10H into place, and it is a great match for the amp, perhaps better synergy than the NAD. Very detailed and open; great soundstage depth and width. Very clean bass. Once again, an easier sound than I had with the M51/N-Core. I think a little bit more air and silkiness at the very top would be an improvement, but that is really nitpicking. The more I listen to the combination the more I admire the really wonderful soundstage presentation and overall tonal balance. The music is just plain enjoyable. Very cool remote, too.
I'm very pleased. As always, matchups are key to this hobby, but this combination is very satisfying, and at a very attractive price. The best, cost-no-object? I'm sure not, but these deliver the goods with very little getting in the way of the music.