Trelja, some interesting insights/arguments but I would not accept hand-wired/made units made over time with possible variances in wiring, solder, caps, tubes, etc. to be close to two mass-produced units. They may be made on the same template, but that hardly makes them identical. A variance in sound, nuanced but there, would be expected.
Perhaps a clarification is in order; I'm not saying that things such as wire, caps, etc. cannot change over time. I am saying that IF they change at all the human typically cannot hear it - it is beneath the human hearing threshold. IOW, it doesn't matter experientially if it is changing or not, to the ear it won't be detected. Hence, my casual comment that it is "not changing." A pair of jeans would obviously be above such a threshold.
I believe I made it clear in my article that transducers were excepted; when a physical motion of a driver is involved there obviously is a break in period.
Regarding coupling capacitors, I have not read the article/test you refer to. Are you saying, then, that the PC test of the changed cap was demonstrated to have made an audible change in the sound of a component. Or, is this an extension logically. IOW, I don't care if capactitor looks different electronically when used/broken in. I care about if the component will sound different.
In my instance of use of two different sets of cdp and integrated amp I had one set which was not burned in and one which was. I would assume the caps in the well used set would perhaps measure differently according to your illustration. However, there was no sonic change in hearing the two side by side. In the end I don't care if you show me a chart of ten things which supposedly measure differently when new vs. used; I care if the sound is changed over time/use. I have not found that to be the case.
I don't think you've made your case convincingly.
Don't lump me in with cable skeptics! I'll quote your last comment, "The subject of break in tracks much like cabling. Even today I meet so many audiophiles who maintain that "wire's just wire." I begrudge them not. Likewise, should you continue to go forth feeling that same way about break-in, I understand"
I would assert that the issue of Break In does not track much like cabling. Cabling is easily demonstrable in a good rig over a very short period of time, even a couple minutes. Break in is not. The one is a matter of swapping out parts, the other a perception based on purported changes over days/weeks/months to the same parts. That is a world of difference.
I do not see any absolute correlation between a person's acceptance/denial of cable efficacy and their perspective on Burn In. I would assume that there might be a mix of audiophiles, some who accept/reject both, and others who hold to one or the other only. In fact, the primary determinant of whether an audiophile accepts or rejects them both likely would be their hearing acuity! :)
Mrtennis, practical answers are usually straightforward. You don't need a complex test to ascertain whether you hear a difference. If the difference between used/new identical components is not discernible then you are wasting your time with Burn In. If the difference is so vanishingly small that you can't be certain it's in effect, then you are wasting your time with it.
Only if the difference would be "wow!" like a different component had been used would it be worth paying attention to. As it is, I get noticeable changes when I replace one or two power cords, or a single digital cable, or a set of ICs. When my friend and I heard the new/used comparison there was nothing different sonically. Ergo, waste of time fretting about Burn in.
The test is simple, and more people should simply do it if they are serious about getting down to the bottom of the issue. :)