I'm using Proac Response 1.5's and currently don't have a preamp. Somehow, the Krell/ARC combination sounds a lot better to my ears. This combination impressed me with better sonics, natural and crystal clear highs and better soundstage. Maybe, it has something to do with the ARC CD3. On the other combo, Wadia directly to M201, somehow, I don't hear that wonderful image and soundstage I hear from the Krell/ARC combo. However, dynamics and bass extension are far more detailed I think. So, I think maybe I'm using the wrong cables or maybe just my ears.