JKF,
Exactly. So called "break in periods" of solid state gear is usually nothing more than getting used to a new sound or picture. I worked briefly in an AV Showroom, and their televisions were completely uncalibrated, including several $10,000+ models.
After I correctly calibrated the sets, one of the more senior salesmen came into the room and told me the picture looked awful! He was so used to seeing it uncalibrated, that he didn't like the picture once it was correctly tuned in even though the calibrated picture was much sharper and more clear than the uncalibrated image.
So give it a week or so, and also try re-calibrating. You have excellent gear, so I doubt very much that there's anything wrong with it. Also, of all the components in your system, the one that's likely to make the least difference in the tonality of the sound is the amplifier. It can have an effect, true, but usually it's not a very pronounced one. If anything, moving to a high-quality amp like the Outlaw will increase resolution and clarity of the sound without affecting the tonal qualities thereof.
Jeff