Danny. If you don't listen to vinyl, my advice to you is to forget about buying a preamp. There are several cd players (tubed and ss) that have volume controls and can drive your Krell amp direct via xlr input. Here is a list off the top of my head / Wadia - Cary - Shanling - and a few others.
As far as ic's, I would go with xlr ends and try to stay away from silver cables. As mentioned above Krell amps can sound a bit harsh and the SL 3 (Sl 3 is quite forward sounding? - correct me if I'm wrong) just adds to that, especially in the upper mids.
Have fun!