Power Cord Burn-In

Scottht,

Passing electrical signals through IC cables can't align
copper or silver grains - there's just not enough energy
there.

In order for the grains to alter, you have to heat the cable
so that you push the material into another phase on the
phase diagram - then cool the cable so that new grains grow.

For example, you may have a metal that is say FCC [ that is
it has a Face Centered Cubic crystal structure. ] You heat
the metal until it reaches a new phase - e.x. BCC [ Body
Centered Cubic structure ]. When you cool the material -
the molecules have to rearrange themselves back into the
FCC phase.

If you cool the metal fast - you will get lots of small
grains. If you cool slowly - you get fewer larger grains.

That's the essence of "heat treatment".

But cables don't get hot enough to heat treat from passing
electrical signals.

Dr. Gregory Greenman
Physicist

I'm not an EE, so I have no clue what happens during "break in", but my common sense tells me that, as Dr. Greenman notes, it doesn't have anything to do with a restructuring of the conductive metal. To me, it seems more reasonable to suppose that the dielectric undergoes some small changes. All I really know is the evidence of my own fallible senses, and they tell me that I often notice a change following a cable break in period.

Okay, Dr. what is your theory on this cable break in falicy?
I have never heard any cable break in. I do hear differences among various cables. But I have never heard changes during the so called break in period.

Scottht,

I'm with you - there are differences between cables because
they are physically different.

A cable is a transmission line - and the dimensions and
geometry of the conductor and the dielectric, and other
physical factors determine the electrical properties of the
cable.

As for "burn-in" - it doesn't physically alter the cable -
hence can't physically alter the electrical transmission
properties of the cable.

Dr. Gregory Greenman
Physicist

Morbius, I'm well aware of what FCC and BCC structures are as are others here, but you might want to look up Dr. Rolf Hummel's book wherein he exhaustively explains in technical terms how and why the break-in phenomenon occurs, covering high and low temperature annealing among other topics. From those who have the book, it is a definitive reference. Few have the equipment and know-how to measure it, but it can be done. I believe Dr. Hummel is at Univ. of Florida.

Brian Walsh
engineer, audiophile and dealer