Shadorne, you keep talking about drift in response, but I don't think that's the issue here. It's not that the design is unstable and therefore faulty, it's that individual circuit components (resistors, capacitors, wire perhaps) undergo some change during the initial hours of their use. This may not show in measurements but I think most of us agree that measurements alone do not the whole story tell.
I have told this story before, but it merits repeating. Back in about 1979, I got a brand new DB Systems DB-6 power amp in for review. Back then, break-in was never discussed as far as I know and it was not part of my audio consciousness whatsoever. I unboxed the amp and hooked it up (with zip cord) to my Quad ESLs. It sounded pretty poor. Oh well, the DB Systems preamp was quite good, I had higher hopes for the power amp. We had family over that night and the system was on, playing in the background. At one point during the evening, I began to notice extraordinary detail and elegance from the system. My brother noticed it as well. The amp sounded great!
This story is not evidence of the truth of break in (it could have been a power issue, or me getting used to things, or who knows what), but it was a defining experience for me as an audiophile (just as was my cycling through a number of different brands of receivers years earlier and puzzling over how different they sounded from one another) and has made me a cautious believer in giving a component some time when new before judging its sound.
I have told this story before, but it merits repeating. Back in about 1979, I got a brand new DB Systems DB-6 power amp in for review. Back then, break-in was never discussed as far as I know and it was not part of my audio consciousness whatsoever. I unboxed the amp and hooked it up (with zip cord) to my Quad ESLs. It sounded pretty poor. Oh well, the DB Systems preamp was quite good, I had higher hopes for the power amp. We had family over that night and the system was on, playing in the background. At one point during the evening, I began to notice extraordinary detail and elegance from the system. My brother noticed it as well. The amp sounded great!
This story is not evidence of the truth of break in (it could have been a power issue, or me getting used to things, or who knows what), but it was a defining experience for me as an audiophile (just as was my cycling through a number of different brands of receivers years earlier and puzzling over how different they sounded from one another) and has made me a cautious believer in giving a component some time when new before judging its sound.