I have had a lot of Krell gear myself and am currently running a Krell KCT to MSB 202 amps and the sound is stunning. Much smoother than the Krell amps but faster too, very very fast! There is so much more music there with the MSB 202 ampsthey are just musical to the core but fast and powerful too. All of my interconnects are solid silver and the preamp line to the amps is a silver plated copper line and it does not sound lean on my Apogee Diva Ultimate's. I have been lucky enough to hear a lot for high end equipment and there is a higher level of gear like FM Acoustics and Vitus that just take you much further and deeper into my music and the MSB 202 amps do that too. I do not think they are the issue for you. The Reference 5 SE preamp is much smoother and has more punch too you may like that?
Rob
Rob