I heard from a few reviewers that the THX 789 (although very powerful, detailed, and well-measuring) sounds cold and rather sterile. So I am not surprised that it's not a pleasant listen. It was based on these observations that I decided not to buy it. They say the same about the SMSL SP200, so apparently it's a feature of the THX 789 technology.
I would have thought accuracy would be the best match for the NH, but perhaps not. I'll hang on to the THX for when I get my Argons and see how that combo works. One of my next purchased will probably be a Denafrips dac. I'm curious to see how a helping of r-2r will fit into the recipe.
I was expecting the Violectric to pair well with the Emu-teak, but no such luck. It does however make the 6xx sound stellar.