Can an unused cable break in?

So we still don't know, and fall back on: Any current however small and it is burning in.

No current and no it will not be burning in.  

I’ve experienced onset odd/poor sound from cables/tubes/electronics that I received via common carriers which eventually resolved itself.

The tubes attracted dust like a magnet so I supected that they had picked up a static charge from the sorting systems, belt transports and scanners used to distribute the packages.

With the tubes I found that thermally cycling them 2-3 times helped (on for for a usually short listening session, then off, then on for the next one).

Most tubes sounded good after this (no longer dust magnets either), but did improve with 10-50 hours of playing time.

Only noticed the dust (cat fur;-) attraction with tubes, but it may have been taking place with the cables/electronics as well.

Never noticed the dust thing with tubes purchased locally from various thrifts and flea markets (mainly from old tube caddies).

Just something to think about.

DeKay

One of the things that is different about power cords vs ICs and speaker cables is there is always voltage present as long as power is supplied whether or not the device is turned on. If the dielectric is the primary thing that burns in, it seems to me it is the capacitive property of the cable that is affected and current shouldn't matter. What say ye?

I agree with Millercarbon's comment about 'burning' in. In my 12 years or so of playing I have always noticed (almost always) that changing gear, cords, interconnects, etc. needs to settle in for several hours if not days to calm or whatever you want to call it. Enjoy!

It’s an interesting prospect.