What Exactly Does "Burn In" do for Electronics?

06-16-14: Zd542
I have some Cardas cables that take forever. 100's of hours.

ZD, as I'm sure you realize I have great respect for your experience and your sonic perceptions. But a question: How do you know that the improvement you are perceiving after 100's of hours is due to the cables, and not to something else in the system that has changed in the meantime? Or, for that matter, something that has changed in the AC power, or even the temperature or humidity of the room?

My question is prompted in particular by reports I have seen here from others about cables and power cords requiring seemingly absurd burn-in durations, e.g., 800 hours or more. Unless, and perhaps even if, that is done independently of operation of the system, such as with a cable cooker, or in a different system, or by using a power cord to power a refrigerator, etc., I don't see how any such changes can be distinguished from effects that may be occurring elsewhere in the system or its environment.

And even if the burn-in is done via one of those alternative methods, given that 800 hours represents more than a month of 24/7 operation, it would still seem very possible that some unrelated effect might occur in the system or its environment in that period, that could be responsible for the perceived change.

Best regards,
-- Al

06-16-14: Almarg

06-16-14: Zd542
I have some Cardas cables that take forever. 100's of hours.
ZD, as I'm sure you realize I have great respect for your experience and your sonic perceptions. But a question: How do you know that the improvement you are perceiving after 100's of hours is due to the cables, and not to something else in the system that has changed in the meantime? Or, for that matter, something that has changed in the AC power, or even the temperature or humidity of the room?

Best regards,
-- Al

Yes as Al has pointed out this this greatly overlooked.
Take any hybrid ESL speaker for instance, they are tuned for a certain sound by the factory.
The esl panel on a day when the humidity is 70%-100% can loose as much as -3db efficiency, making the balance sound bass heavy as the dynamic bass driver has not lost this -3db.
I have measured it on my new panels, dry day 5kv bias charge and on a humid day 3kv-4kv bias charge, I tend not to do any evaluations or serious listening on days when the humidity is above 70%. Or if I have to, I can with some trouble turn down the gain of the bass electronics by the appropriate amount so all is balanced again.

Cheers George

From a teleological point of view, it makes great sense for our auditory system to be good at classifying sounds while ignoring minor differences. You needed to know if a predator or something to eat is is nearby. It wouldn't have served our survival well if we attended to small differences in sound. Audiophilia is but a recent pin point on the evolutionary scale.

My early research was concerned with testing theories of binaural hearing, so I've done lots of forced-choice listening under lab conditions. We can tricked into attending to small details, but we aren't all that consistent in doing so, and variability among listeners usually swamps those differences.

Count me with the skeptics, although I'd swear I can hear break in of disc players.

db

Makes sense.

I do think I hear a difference with some new power cords, but so subtle its hard to be certain.

I definitely hear differences with different analog ICs. DIgital ones, less so.

And rolling tubes in my tube DAC....absolutely no doubt.

I think burn in is a real consideration for mechanical devices, like speakers. ALso for some electronic components, like caps and probably transistors.

I suspect there is "burn-in" aspect with wires as well, but to a lesser extent that might matter less practically in most cases.

It's shades of grey, not black/white. No two things are exactly the same nor do they remain 100% constant over time, but practical effect may still be insignificant or even nonexistent in many cases.

Almarg is correct to point out that there can be many factors at play to account for perceived differences over time, and isolating each is difficult in practice, especially outside of a highly controlled envrionment, like a laboratory. When the differences are subtle on teh grand scale of things, one must always wonder and not be too quick to associate cause and effect.

I guess it is the term "burn-in" that piqued my interest - I inferred a physical change, and there very well may be - whether magnetism, heat, or some "alchematic" result, lol. Anyway, it is very interesting, and I wonder if the those changes have ever been measured? I assume possibly resistance, and other qualities surely have, over time. My equipment has most always been pre-owned, so I have not really experienced the change. I appreciate the discussion and I definitely didn't start this thread to instigate argument.