I have not really noticed a change over the course of one listening session. Fortunately, I don't have perfect pitch ;) The changes were from day to day - and I can measure these at the wall with my multimeter! Once the motor, etc. warms up (an hour or less), I'm hoping a DC battery will help things. I'll keep y'all posted. By the way, this all has pushed me enough to want to DC power my entire setup, using a big'ol battery and a DC/AC inverter. Thanks Tom for the advice :)
TJ
TJ