Thanks Jeff and Brf, I suppose I'll just have to be patient. I thought that break-in may be an issue, but I didn't know just how much of a difference it would make. I've had sound change over time with some components, but very rarely does it change drastically. I can remember one experience with an interconnect when the sound changed drastically over time though, so it is a possiblility.
I really like the bass and midrange performance of the XX mk II, but the high's are definitely too rolled off for me. I know that it is a new cartridge, and a new preamp too, so I will be patient. That is not easy for me. ;-)