Difference between krell KRC-2 & KRC-2 HR?

could someone please explain the difference between these two preamps to me. Is there a real difference in the sound?

I used to own the KRC-3 but I'm using the KRC-HR now. The sonic difference is a lot. The clarity offered by the KRC-HR is quite stunning. Much much clearer. You have to audtion both models in the same set-up to hear the difference. The KRC-HR used to be Krell flagship pre-amp. My KRC-HR have the optional phono card. It's the deluxe phono card. You supposed to have two options with regards to the phono card, the entry and the deluxe version. Hope this helps.
Vincentpiazza, I'm no expert on Krell gear, but I do know that Mets catcher Mike Piazza is an endorser of theirs. Any direct connection, or influence on your choice of brand? :-)