I see two fundamental flaws with SS amp warmup and the audible differences people claim they hear. 1) The warmer the transistor becomes, the more thermal or Johnson noise is generated at the junctions of the transistor. It may or may not be audible but the point is that noise generation is increased at the junctions. 2) The warm up time claimed by people is many magnitudes greater than the time required to accurately recall the sound they were hearing when the amp was first powered on.