hi arthur:
live sound is correct instrumental timbre. when you listen to a musician play an instrument in a "room" or "hall" that is reasonably acoustically benign, you hear live sound.
how well we can store in our brain "live sound" and make meaningful comparisons with the sound of a stereo system is another consideration.
as to tube rolling, very often replacing the tubes has a minimal affect on the sound of a stereo system. i would say change the tubes as long as you create a presentation you prefer to what you hear with the stock tubes.
live sound is correct instrumental timbre. when you listen to a musician play an instrument in a "room" or "hall" that is reasonably acoustically benign, you hear live sound.
how well we can store in our brain "live sound" and make meaningful comparisons with the sound of a stereo system is another consideration.
as to tube rolling, very often replacing the tubes has a minimal affect on the sound of a stereo system. i would say change the tubes as long as you create a presentation you prefer to what you hear with the stock tubes.