"Burn in" Are you serious?

Recently replaced my preamp/amp with an integrated unit (a demo, presumably already broken in) and my first impression was that the integrated had slower, more rounded bass and slightly elevated extreme high frequencies than the units it replaced. As the weeks have passed the amp no longer sounds this way. Is it burn-in, or have I acclimated myself to the sound of the amp? I can't really say it's one or the other. Probably a little of both.

If burn-in exists, I have no proof or indication. My psychological state seems to have more of an effect on how my system sounds than any burn-in. After the second beer my system sounds much better. If burn in exists, it is likely to be very subtle and gradual. With all due respect I am not convinced by any of those above who argue that there is a huge burn-in effect. Opening or closing a cabinet door neer my room reflection points, changing the position of the blinds, etc. has a much bigger effect on the sound than burn-in could possibly have. Do you have an anechoic chamber ? Then I may be convinced that you can detect burn-in.

I suspect your hearing is not sensitive to it Joe. This is not implying you don't hear well, because the effect is not gross, is not like the difference between having the blinds shut or open, or like the difference between two components. It is a quality that flattens images, takes a feeling of weight out of bass, adds a mechanical/electronic quality. And I don't care if you are convinced or not. I don't visit this forum to win arguments (which is not to say I don't fall into the trap of becoming embroiled in them from time to time) - just to share experiences with others - and your experience (and that of others) of not hearing components burn in is interesting and perplexing. But I feel no need to require you to prove that burn in does not exist. I cannot quite understand your concern about proof.

We KNOW our system's sound: We KNOW how does the system sound compare with live sound, we KNOW where the shortcomings are and we also KNOW burn-in is for real.( Inside that is. Outside we might brag whatever)

I agree that not everyone is equally influenced by the effects of burn it. I unfortunately, am one of the more sensitive to this problem, and really have to exercise caution when testing. This is not a new or revolutionary thought within the audio industry. Even in the early 1980's, people such as Steve McCormack, Bill Lowe (Audioquest), Jim Aud (Purist) and Richard Vandersteen, among others, advised us about the existence of break in. These manufacturers have more recently been followed by a majority of the high end community, in recognizing the fact that this is a real part of the evolution of the sound.