Love getting new equipment, hate the break-in

Burn-in is real, for sure. But it is in your ears/auditory center. That is referred to as habituation. I challenge anybody to do a blind A-B test with a burnt-in component vs out of the box. Good luck! Re capacitor formation/degradation etc., the question is, does it matter, is it audible?

BTW: null hypothesis in statistical testing is "no difference".

A genuine new, be it OS or current production, signal tube will demonstrate improvement in performance with time, to a point upon which it levels off, relative to initial performance.

@oberoniaomnia  Statistics don't mean doodly-squat.  Did you verify this on Youtube?

@boxcarman Oh dear! 

I'm actually a MINT scientist. Have published in peer reviewed journals using statistics, like breakpoint regressions, Discriminant Function Analysis, various flavors of (M)AN(C)OVA etc. Got my first editorial appointment fresh out of grad school because, as a reviewer, I found a fundamental statistics problem in a ms, based on a dissertation passed by a fully accredited US university [used PCA instead of DFA to show differences between groups, btw. And if you don't immediately see the problem, you know doodly-squat about statistics. But that was clear from the outset anyway.].

No, I don't need YouTube re statistics. Thanks for asking.

@roadcykler 

They DON’T always sound better -- what an idiotic suggestion!  They simply reach a point where the sound stabilizes. 

In fact, I just dropped off a DAC I’m returning at UPS this afternoon because, once the presentation stabilized, I didn’t like it. FYI, it yo-yo’d back and forth between between dull and bright several times before finally settling in. I’ve found the length of burn-in and degree of change with different pieces of gear can vary significantly.  

If you don’t hear it, fine. One less consideration for you. Just know that your contemptuous attitude is unlikely to convince many that you are somehow superior.