Amplifier Power tubes - important to sound?

@immatthewj Apparently you're the only one not oblivious to the fact that OP started an identical thread to this back in February...and responses have been pretty much the same....maybe this is a test?

@wyoboy , I have come to the conclusion that OP's questions are not serious and that he is not interested in serious answers.  

@emergingsoul OK so you started this same discussion in February of this year--did you not like what you heard at that time?  Or did you forget?  Or were you just seeking confirmation of what was said back then?  And if the answer was different this time then what?

My thoughtful niece tells me that having Alzheimer’s can lead to a wonderful experience of being able to watch really great movies over and over again.

Of course when she drops me off in the middle of nowhere or in a shopping mall I wonder why.

Yes very important also important is coupling capacitor(s) for cleaner sound quality of the amp

Right out of the Mc 901 manual:  

The MC901 will function optimally with any correct tube type that is functioning within the design specifications of the MC901. Only when a Tube falls outside of the acceptable range will any diminishing of performance be heard. Because McIntosh Tube Amplifiers are engineered to use Tubes in a way that does not rely on the Tube’s individual character and can perform perfectly provided the specifications are met, there is no advantage to seeking out expensive esoteric tubes.