Need advice ono a Tube preamp

I have never tried tubes.I am currently running B+W matrix 801s seriesIII.I have several bryston amps a few 3b ssts,4b sst and 3 bst.I also just purchased a sony scd-1 and a moon eclipse.
I wanted to try a tube preamp in this system.I have never tried one and I know little or nothing about them.OK,I know nothing about them is more like it...lol...
I don't want to sacrifice bass response,channel seperation etc but want to warm up the highs abit.Is this possible with a tube preamp or Should I try something else?