Triangle Titus Xs

Love 'em. They take FOREVER to break in. Quite literally, my Celius didn't get smooth until 500 hrs of usage. They are amazing. They, in my view, blew away Dali, Gallo and the B&W 700 series, most of which were more expensive.

Well, not sure what you mean by unique sound. To me they are very transparent, fast, revealing, clean. That may, however, not necessarily be a good thing if your other component are not up to the task; When I introduced Triangles into my system several years ago, they sounded quite harsh undil I addressed the source and reduced jitter (Digital cable, Monarchy DIP). I eventually upgraded every other component in my system... but kept the Triangles... and they just kept on sounding better and better...

My experience is that triangle speakers don't match that well with NAD amps.

Triangle Titus XS is a very easy load for most any amp to drive. Each amp will sound different, including NAD. YMMV. They are very fast and clean sounding and very tube amp friendly. Can get a touch hot sounding with some SS amps. I have used with various SS amps, including Class D. Each has its charms. Would like to try a modest powered tube integrated someday, like Rogue, Unison or other. Integrate a sub or two well and there may be little to want.