That's a strange combination you have going on there, too dark and hard. Usually it's dark and soft or bright and hard. All I can figure is the Cardas is the dark and the Krell is the hard. Going to the Nordost should eliminate the dark, which would mean you're looking for a softer cd player? Again, I would go one step at a time, replace the Cardas and AQ with the Nordost and report back. If it still sounds too hard, I'd try a Classe CDP-1 cd player. I had one a couple years ago and it was smooth and punchy. You should be able to get one for well under a kilobuck.
Regards,
John
Regards,
John