I think you will be happy with either choice. I have the Krell HTS 7.1 & think the preamp section is a strong suit. I use my Krell with the Cary Cinema 5 amp, and the sound quality is outstanding. Prior to that I was using a set of Krell KAV series amps. Those amps were on the brighter side, but I think that is specific to that series of amps. Overall, I think the HTS is exceptionally nuetral preamp.
I have not heard the SSP 75, but have listened to the new SSP 30. It was nice, but I prefered the Krell. A recent review of the SSP60 indicated sound quality on par with the SSP 75, but with more features. I would propbaly be inclined to go with the newer design. I realize you are more into 2 channel, but the newer design has full bandwidth video and DPII (a noticeable improvement from DP). Can you audition the SSP 60 vs. the SSP 75?
Either way, you are looking at preamps which excel at the music side of the equation.