Why does it take so many hours to brea in arc preamps and amps?


I recently purchased a like new ARC 5 SE pre amp.  The unit had less than 200 hours on it.  Everything I have read states that ARC preamps take up to 600 hours to fully break in.  Why is this so and what improvements can I expect to hear as the unit accrues hours?
ewah
I've never heard anyone say that their component sounded worse after break in.  If break in is a real phenomenon, then statistically how is that possible?  Unless it explains why we constantly 'upgrade' to new gear.  What if gear only sounded good for 1-200 hours, and then it was all downhill from there.  Obviously, over very long periods of time component parts degrade and do need replacement.  But I would not call that part of "break in."
Most of my experience with break-in (as opposed to warm-up) is with speaker crossovers, and caps. Replacing a cap takes at least 24-72 hours for them to settle in and give you a "final" version of the sound.

I wish I understood the physics. :) I understand one hypothesis that is often stated as likely is placebo. I understand why it’s such a possible and easy answer but to me it’s not enough.

Like other things in Audio, it remains an area not fully explored. I hope someday there will be results that better explain what we perceive.

Best,

E
I’ll add transformers to my above post...

tho I have seen reviewers say the teflon caps.

The real question is what ARC says...

Anyway just leave the system on with a CD on repeat or something while you run errands, etc.


BTW, having a "long" break-in time isn't necessarily indicative of Teflon caps. I've had ARC gear that claimed a 500 hour break in with nothing fancier than Wima polypropylene caps.