Ive heard the Nad 326bee with the 685.
I found it to be too dark for my liking, muffled and lacks excitement - with a ton of unnecessary bass. Others though, may like it, but as far as my subjective taste is concerned, its a No.
The 685 however sang good music with a tubed el34 and a SS Rotel
The nad naturally performed great with the PSB speakers
Cheers