Chesseroo:
hmmm, no arguement over the possibility of marketing hype when they claim the break-in process is necessary, although not absolutely.
Now the fun part about cpu, it's a whole new discussion and it's going to take pages to explain the architecture and nature of microprocessor and it's relation to other electronics. But in the nutshell, burning in a semiconductor devices is nothing but a process that uses a specific type of environment stress on an accelerated basis within design capability, in this case normally a burn-in software is being use, typically 24hr, certain units could be as long as 1 week straight.
The purpose is to detect latent flaws and defects that have a high probability of surfacing as infant mortality failures under field conditions. In doing so, what do you think is going to occur? Electromigration, to a certain degree. I'll try to put it in the simplest way, either you cleared up the restricted metal ions (or pipe lines if you will) and allow more electric current to flow through, or the electrons get congested and eventually will change the flowing pattern.
And what do all these translated to? something was being changed. True, amplifiers are not as complicated as computers, but similar result still happen to the circuit board, chipsets, and many other components within the unit. An amplifier doesn't has as much pipe-lines or circuits as a computer, but electrons that passes through the metal ion surface are much greater and stronger than you could ever imagine, ever get shocked by messing around with a monitor, old tv, or powersupply?? :-) This is not a rule, but simply the law of physics and the nature of electronics, and I strongly believe the changes that took place during or after the electromigration is the main reason why some of those amplifiers or receivers MIGHT sound different after a period of time.
On the other hand, I'm not going to rule out the placebo effect either. I'm sure you've heard countless of people tend to let their equipments run for a week or two and didn't pay much attention to them at first, then they'll proceed and do the "serious" and critical listening afterward. Well, since you didn't pay as much attention to the music in the beginning, of course you are going to notice much more details and soundstage/imaging later on, because you ARE expecting to hear them.
