NAD Preamp

I've owned the NAD c165BEE preamp since new for almost four years and its been completely trouble free and very well made. As far as sound quality is concerned, I think it sounds real good and is very neutral. I also have tube preamp in another system and occasionally switch between the two systems. I can tell the tubes add the so-called warmth and glow to the sound and the voices/midrange is more pronounced but the NAD is just more balanced across the board. If you like a neutral sounding preamp the NAD is a good choice. It has a lot of features that much more expensive preamps offer, like relay switched inputs, class A input, high quality motorized volume control, etc.   

I tried the Parasound P5 before settling on the NAD. To my ears the NAD sounded better; better soundstage and better bass. Its currently paired with my Vincent SP-331 amp and the combination is relatively "musical" with help from the tube input stage in the Vincent. You may want to consider a tube preamp with the A21 to warm up the SS sound. A fairly popular combination.