I haven't noticed my NFB-7 leaning to the 'bright side of neutral'. I doubt the Master-7 will be much different as both are described as neutral.
I recommend you give your amp time to settle in first. I have heard people say that Krell amps can be 'lively' in the highs especially when new.
Nice to hear your thoughts though.
I guess it's not the DAC then. The Krell was bought used from agon. After a took a shower last night and listen a bit more before bed, I didn't notice anymore fatigue.
So it's perfectly safe for class A gear to run at ~50C?