What is "live" sound?
Yes but recorded sound is not live. Therefore you roll tubes to find the sound you think sounds live. The equipment manufacturer may have used a tube that you think sounds live in which case no need. In general Ihave found that I get the most pleasing sound if I roll tubes. On occasion I don't, but it's the exception not the rule.
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.
I am sorry but an instrument played in a "room" versus a "hall" will sound very different. That was my point. Mechans got it right - "live" sound is what we "think" is live sound and your live sound won't be like my live sound and the live sound of a band playing outside won't be the live sound of that band played on a stereo and a classical symphony in a concert hall's live sound won't be that live in a stereo room either. Live sound won't ever have an absolute reference, I assure you.
Just find what you "think" is live and all is well. Otherwise you will never be satisfied in this hobby and you will spend the rest of your days searching for the "best" stereo in frustration. Just read many of the posts people have here in this forum if you want examples.
if you listen to a tenor sax in a venue 1 where the musician is away from room boundaries and you are say, 10 feet away, and then listen to a tenor sax in a larger room and the musician is still far away from room boundaries and you are 10 feet away, the perceived timbre in each case will be very close.
the point is there is similarity in timbre from venue to venue so that one can form an idea of what a tenor sax sounds like. the recall of such experiences is more of a problem than the differences in instrumental timbre.
when one hears a recording of a tenor, one has no idea what the recording sounds like. listening to live music is better than not listening to live music, for the purpose of configuring a stereo system.
I never said you shouldn't listen to live music.
I don't understand why so many people assume recording processes are perfect enough to voice their stereo with it. Which CD do you choose? haha
Getting the right sound is a subjective process because there is no absolute reference. We make it sound the way we assume it should be. One man's live-sounding stereo is another man's bright-and-shrill stereo.
By the way, "timber in each case will be very close," doesn't mean exactly the same. This was my point. A hifi stereo takes "very close," very seriously. Otherwise, we would all have $500 stereo systems and be satisfied with that.