Does tube rolling with regard to CDP mean...

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.

hi arthur:

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.