a bit odd question.....

If you put under cryogenic treatment some cables (already existent in my system) , you will need again to burn-in the cables?
cause of the molecular structure difference after cryogenic treatment.
Cryo'ing doesn't really change the molecular (crystalline) structure if the metal. It just causes them to pack more tightly, thus making better electrical contact.

Burn-in has a lot to do with "settling" the interface between the conductor(s) and the dielectric material. So I'm not sure how cryo would affect that. I would say a qualified "yes" but probably not as much as when the cable was new.
After having your cables cryo’d, you will definitely hear an improvement by putting time on them. In other words burn them in once again.
Nsgarch: I keep reading and trying to understand your repsonse. If the molecules that make up the metal simply pack more tightly, then that would say that they take up less total space.

That is, if they were some distance apart, and now are closer together, then the total outside dimension of the metal must have changed or some part of the original metal would now have no molecules and would be empty space, or then, really be made up of nothing - unless you are saying the cryo process will also create new molecules to fill that space??
pleezeus, if I understand you correctly, you are saying the metal must shrink after cryoing. You're probably right, though I expect it wouldn't be a whole lot since metals are not known for their porosity. But an interesting point nevertheless -- I never really thought about it.

All the descriptions I've read about the cryo process basically say the same thing: which is that cryoing eliminates/reduces the spaces in the crystalline structure of metals. I'm not sure what effect (if any) the process has on non-metallic substances.