Beware of the cable claiming long burn in period.

One poster wrote, " I had used Kimber PBJ for the 7 meter run, and back then, I never noticed any change but I was not looking for any". Interesting, that some people are looking for the change in sound. Perhaps if you were not  looking for a change you would not find it. 

If you keep your eyes shut tight, I am certain you will not see anything.. either.   But I do agree if you are not looking, you probably will not notice. What it seems tobor007 is trying to write is if folks in general did not expect changes, they would not notice them?? So stop looking and you will not find. (interesting advice)    
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I am the poster with a 7 meter Kimber PBJ,, (back around ?? 1990?) It was the first cable I used at all in such a long run. The main reason I did not hear 'any differences' is I had never had that setup before anyway, so nothing to compare, except to a short run where all the equipment was next to the speakers. (also PBJ IC) So in particular, I would say in hindsight, Kimber PBJ sounds the same whether a short run, or a long run.            
One cable that proved to NOT be the case was Cardas Parsec. Where a short Parsec XLR sounds great. but a long 7m run sounded thin and basically sucked. (I returned the 7m, and still use the 1 meter Parsec) I went for Kimber KS1116 mainy because it has triple wires, six instead of the 2 in the KS1111. better for a long run IMO. And yeah is turned out to be just right for that application.
Getting back to tobot007... I can see the idea... but it just is not gonna work out for most audiophiles. Maybe for a person who wants 'plug and play', easy to ignore any differences, say when they have to buy a new turntable cartridge. Since they don't care.

Good point. "If you keep your eyes shut tight, I am certain you will not see anything.. either." With your eyes still closed ask yourself, can I hear the difference?

Burn in is a myth. This is simply people getting used to the sound of something over time and enjoying it more.

Even if it’s a myth I’ll take it...as long as it works. A myth is as good as a mile.

Metaphors be with you.