Equipment Break-in: Fact or Fiction

From my experience, after about 20 to 30 hours what you hear is what you are (stuck?) left with. I agree with Marakanetz - the sound does not magically improve after a "break-in". What I noticed, whether source, amp or speaker, is only the imaging and soundstage pulling together; the song remains the same.

I am running a Sony SACD player at the moment,the common response on this and similar Sony models is approx 400 hours burn in.
I'm keeping notes so I'll update you with my dillusions or solid facts when I get there-at 180 hours so far.
I know this is an emotional subject but why get upset,trust yourself either way.

Break in is VERY real, I recently had a chance to compare two identical pieces and there were HUGE differences between the two. I had 2 audio aero capitoles mkII, mine had about 350 hours on it and the other one was opened and plugged in for the first time, we used the same exact system just with two of the same components, and the burned in unit, had depth, warmth, musicality, dynamics, higher resolution- over all an ease of presentation on the whole system compared to the NIB unit. I was skeptic till I had the chance to actually compare side by side and boy o' boy burn in is a very real thing, and that's a fact Jack!(as Timo so eloquently stated).

SOS, I share your sense of shock, only, in my case, it's based on the fact that guys like you can't accept the power of suggestion on the human mind and the simple fact that whatever we get used to becomes our personal benchmark. Since you sell the stuff, I think you should be believed without reservation. I have a question for you, and all others knowledgeable in this audio thing: when does the process of burn-in stop? Does it go on and on and on ad infinitum until the piece of gear is so good we call it "vintage" and never sell it or is there a plateau that is reached, and if so, how long is that plateau? Does the plateau (geez let's call it "stasis" ) last forever or does the component fall off at some point? Or maybe, just maybe, since "everything changes and that's fact, but everything that changes some day comes back" (sorry Bruce) do we have to start over again if the product is left on a shelf unused for a while? I heard from reliable sources that this is the case with cables, slinky little devils! Or maybe the component just becomes better and better until such time as degenerative cap and diode syndrome sets in, at which point the component should be tossed in favour of something newer. Kind of like adopting a cat or dog, you grow with the component, but, ultimately, the end comes... This last possibility has the greatest on the up-side though for the "industry": just imagine a "best before date" to keep your customers coming back! No hard feelings, but as the good Bishop indicated, we will never know will we? Good day.

when you don't believe, then have heard it happening, do you still not believe? I was once skeptical until my own experience taught me that a few hundred hours on a component made a considerable difference - for THAT component. Any other box will not behave exactly the same way; may or may not happen (some do & some don't).