I have the Steelhead running directly into my Tenor 300hp amps (this replaced the Groove phonostage running through a Hovland HP 100 pre-amp). The sound running directly through to the amp is very pure - great resolution and very natural. At first it sounded a little odd, but once you actually listen to what is happening, you realize you are hearing much deeper into the music. You should also try using the moving magnet input instead of the MC (even if you are running a MC cartridge). I was using the MC input for a year (Dynavector XV-1S on a VPI HRX table) and I really enjoyed it. One weekend, I had alot of work to do (which I do in front of my stereo), so I figured I would compare the diffeences in sound between the 2 inputs. I spent a full day A/Bing on various albums. At first the music sounded a bit threadbare, but like the change to no preamp, I soon realized I was hearing a much clearer sound. You can really hear the texture of the notes and feel the fingers running over a guitar strings. The sound is less full, but it is not lacking in warmth. Give it a try. It may not be for you, but it certainly is worthwhile to try.
