Evolving: in my experience the preamp has more influence on the upper frequencies than does the amplifier. At least when you get to a certain level of performance. I don't have any experience with Musical Fidelity components so I can't talk about their sonic signature. But yes, going from a Krell to just about anything, you better not rely on anything but your own ears, because Krells do have the reputation of NOT being soft or rolled off in the top end. Good luck.