Tim-I mostly agree with everything you said and Frank is driving us all together as Jack pointed out. I do believe the system can change from day to day and for a number of reasons. Thankfully for you, I don't think your system (a digital based system) will change as much as those that involve turntables and R2R decks. First of all, if you don't warm up your gear for the same amount of time before you sit down to listen, cold gear will sound different. Back in the days when I had all SS preamps and poweramps, I never turned them off. I didn't care how much extra it ran up the electric bill. I am firmly convinced that SS sounds better if left on all the time. Obviously if you have a pure Class A amp, you can't do that. Even my Denon AVR receiver which has been in my upstairs home theater system for over 8 years has never been turned off except for when a really bad thunderstorm strikes. Temperature and humidity can also have an effect on phono cartridges.
My point to all of this is that if you just flip your system on from a dead-cold state and start to listen, it won't sound like it will after it has been on for awhile and everything has reached thermal equalibrium/temperature stability.
Mep- silicon device's current will change by temperature, so SS OCL amp's out put voltage will shift by the change of the temperature, stable temperature is needed, and my all tube system's sound always getting better after one side of a LP done, if a guy can't hear the difference in this area, can he notice the different between a brand new amp and after break in ?
tony ma