It's not clear if you're using the DVD player as a full blown CD player or just as a transport, but definitely don't use it as a CD player. If you are, change to using it just as a transport and feed the digital signal to the HTS. The HTS doesn't have analog pass-thru, so you're going through two conversions you don't need if you're using the DVD player as a CD player into the HTS. Because of that lack of pass-thru, I'm doubting that any CD player purchase will change the performance of your system. If you have one of the HTS2 that do have that feature, then I'd most definitely recommend a good CD player in lieu of a transport into the Krell. I'd recommend a used Arcam FMJ23 or, for a bit more, a Muse Model 9 (regular or Signature). I have a very similar system to yours (same basic speaker setup, similar amplification quality) and recently added the Muse to my great satisfaction.
You don't mention your room - perhaps setup is an issue? Also - run a couple (few?) dedicated 20amp circuits to your setup if you haven't already. -Kirk