Hi seanheis1, I am not sure what circuit components are most prone to evolving during break-in.... I suspect that it is just about everything, from resistors, caps, boards, conducting traces, grounding surfaces, connectors, dyelectrics.... According to Jeff ROwland, capacitors and transformers are particularly slow at breaking in.... And am not sure what is the electro-magnetic phenomenon at play either. I only know that I invariably experience significant audible evolution during break-in.... And it is not a particularly linear phenomenon either..... there are lots of dips and peaks during this period.... Gradually tapering off.
ICEpower modules seem particularly unattractive out of the box.... a more benign break-in curve can be experienced with NCore NC1200 and Pascal M-Pro2.... But do not expect miracles from any brand new class-D amp.... My experience is that patience does remain Golden *Grins!*