Equipment Break-in: Fact or Fiction

I am an Electronic designer. Mostly high speed digital
and alot of analog/digital mixed signal stuff. Up until
about six months ago i would have said there is a break
in but it should be pretty quick (for electronic gear)for
things to stabalize.

But now that I have burned in a Bel Canto EVO6 i will
say that i was amazed at how long it took. The documentation
said about 40hrs. I heard subtle differences all the way
to 300hrs. The dealer i bought from said anywhere from
100-200. Before i went thru it i would have never guessed
it to take that long.

In my opinion the biggest factor is the material used in
the PCB and component fabrication. There are many different
materials and many different properties such as:

Coefficient of thermal expansion (change in length per unit in all directions x,y and z thickness. This is different for all materials. FR4 the most widely used PCB material expands more in the z than it does in the x,y.

Also moisture can play a part in the whole process. I have
seen PCB's not function at all because they werent baked
long enough. And where you live and how much humidity
can play a part in performance. For example I have done a
lot of work for the Dept of Defense and we had to use conformal coating on PCB's to be used for ground and air applications. Sometimes PCB's have to be moisture proof.

Dielectric constant Er changing as materials are burning in could also play a part in burn in.

The difference is with a most products or anything else Analog or Digital. If there is too much noise or clock jitter or whatever the case may be the device wont work and sometimes even if its noisy and it works we dont hear it.

With audio especially the high end stuff WE HEAR EVERYTHING.

One of the reasons i went with the Bel Canto is its a solid state device and very efficient so they recomend leaving it
on for sonic stability. It works extremly well. I love it.

So i cant put my finger on why Exactly and i certainly dont
claim to have all the answers all i can say is i have ABSOLUTELY heard the differences. But then again I could be ABSOLUTELY nuts like some of the other audio people who swear by certain things.

Best regards to all..

Geez nobody answered my questions, I still want to know:

1) does break-in stop after a while or is the process continuous such that the component will sound only better as time passes; or
2)does it reach a plateau that goes on forever;or
3) does it get better as it burns-in up to an apex and then starts deteriorating until such time the component sounds like s..t.

BTW I will not hold the fact that anyone is an engineer against him/her.

In an ever changing world, life is rough.

Good day.

I think # 3 would be closest.

Except that I would expect DIGITAL components to fail before audibly changing.
And PASSIVE components would be the most likely to
drift before failing.
80% of all PCB failures are do to solderjoint problems. When the components with the solderjoint problems are replaced they have new solderjoints and most of the time the problem is blamed on components. Not true.
As far as tubes go.. I cant comment.. I dont know reliabilty. I do have tube guitar amps but havent heard a audible difference yet and no failures.

I have had audio equipment play the same (not very well)
for 20 years.

So the answer is all of the above.

And are we just arguing about how many angels fit on the head of a pin? Which ever it is that is burning in, the point is we have to be careful to spend time with components before we make judgements. This is what makes this hobby so hard, and why we need to listen with open minds to the experiences of others - and not dismiss experiences of others through lack of proof.

Redkiwi .. here here! Some think burn-in is in one's head. Others think it's in the equipment. Neither side appears to have presented conclusive evidence (electrical measurements, or psychoacoustical studies), so lets all be happy to differ. So long as we're all pleased with the end result.