Isn't the DSi200 a class D amp? Not sure you are going to get much warmth with that. An ARC tube pre would work very well with the Bryston amp.
ARC DSI200 or Bryston 4bsst2 & ARC SP16L
Currently own a Bryston 4bsst2 amp. I'm about to try a ARC SP16L as the preamp, but I'm also loving the look of the DSI200 by ARC. I'm considering selling the Bryston amp to finance the DSi200. I'm trying to get a little more warmth from my system due to a recent speaker change that can benefit from some added warmth. Comments appreciated. : )