Having problems with sound out of cat/krell setup

I am trying out a cat sl-1 ultimate preamp with a krell ksa-300s and the sound is very bad. The lower midrange is very harsh and overwelming. Any thoughts on what might be wrong, I can't see such a highly acclaimed preamp sounding this bad. I was using a Krell krc-2 before, Im new to the tube world as i have allways been a solid state person. Thanks in advance for any ideas on what might be wrong.