I realize this is an entirely subjective exercise - caveat delivered. I listened to the 400, and love treble and high midrange, but found them to be a bit hard & metallic in this regard. Could have been speakers, cable or source CD, but after trying a few variations on the theme, it seemed to be the Krell. To be fair, not sure if it requires an extended break-in period, but this was my experience at the dealer. Higher end Krell amps didn't seem to exhibit this characteristic, and were remarkably high in quality, but that particular experience was the only thing that kept me from the purchase. Otherwise, iron grip, silent backgrounds and a high degree of detail were the pluses. Carefully matched speakers that will take the edge off harsh highs while retaining the essential details (the Dali Helicon 400 comes to mind) may moderate the treble/mid effect.