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Old 24th February 2014, 02:17 PM   #48541
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Quote:
Originally Posted by jcx View Post
it is just too suspicious that "burn in" is Always an Audible Improvement

not likely if it were objective materials property changes causing real electrical circuit performance changes - at least some changes could be expected to go the "wrong" way, stablize at a less optimal state after burn in
That goes for many other things, "always" an improvement from tweek A, B and C, and of course they always add with more positive result.

BTW has anyone walked through a PA schematic and figured out how few parts are actually highly stressed by 80% power into rated load?
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Last edited by scott wurcer; 24th February 2014 at 02:29 PM.
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Old 24th February 2014, 02:21 PM   #48542
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the early problems with the Hubble
Ironic how stupid the real reasons were, kind of like not noticing your car has two different sized tires until you drive away.
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Old 24th February 2014, 02:29 PM   #48543
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Quote:
Originally Posted by jcx View Post
it is just too suspicious that "burn in" is Always an Audible Improvement

not likely if it were objective materials property changes causing real electrical circuit performance changes - at least some changes could be expected to go the "wrong" way, stablize at a less optimal state after burn in
In line with my mention of initial 'burn-in', I have also found that an amp can permanently change for the worse subjectively by being temporarily pushed too far into very hard clipping.

Dan.
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Old 24th February 2014, 03:19 PM   #48544
hhoyt is offline hhoyt  United States
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Default Burn-in

Quote:
Originally Posted by jcx View Post
it is just too suspicious that "burn in" is Always an Audible Improvement

not likely if it were objective materials property changes causing real electrical circuit performance changes - at least some changes could be expected to go the "wrong" way, stablize at a less optimal state after burn in
jcx, this is an excellent point. There is no reason why the components, if they did change, would all drift in a way that made the unit perform better. That thought is just wishful speculation. If it were so, would not the design have to be optimized using the unknown end-drift parameters, not the as-designed component values?

I actually have a lot of experience with this exact issue: I designed a burn-in CD under contract with a well-known audiophile label. I was originally undecided about burn in until I did the project, so I spent hundreds of hours analyzing other burn-in discs and trying them out on a range of new studio systems at work before creating my own. I utilized a range of B&K 4000 series mics, TEFs and Audio Precision equipment to evaluate new speakers and equipment, as well as many hours of listening, and my conclusion is: Speakers do indeed change from new as the suspensions condition, but burning in electronics only generates heat and ages components. I advised my client of my findings, but the project was not cancelled, make your own conclusions as to why. I finished the CD project with difficulty since there were few metrics to guide the design, yet the finished disc was lauded as one of the best break-in discs ever, much to my confusion. This disc has gone on to sell tens of thousands of units commercially.

The fact is the best performing components used in the most critical applications are at spec when just assembled, and do NOT improve as the unit is used. I am talking about applications far more severe and particular than audio such as deep-space telemetry, medical devices and others. And before the objection is raised that these applications also burn-in critical components, this kind of "burn-in" is used to weed out infant mortality, not improve the performance of parts. I'm sure Scott Wurcer has volumes of information on this issue.

There is a lot of psychology involved in the idea of audio component break-in, and THAT is where the research should go, not in making up theories why the actual devices are changing. I do not doubt for one second that people who support these claims actually believe what they are hearing, and that is what is important, because listening to audio is a brain activity. The problem comes when attempts are made to warp physical reality to match their perceptions.

My current thought about the nature of the "break-in" phenomenon is: our hearing is partly mechanical in the inner ear, but mostly a brain activity carried out in several part of the brain. Our sensory processing is designed to normalize and subtract out sustained stimulus. This is why a constant background noise becomes inaudible after a while. To use the evolutionary analogy; If we couldn't normalize to the sound of the wind through the trees we wouldn't hear the approaching tiger.

So when you are breaking-in an amp, your brain is becoming used to your system's characteristics with the amp in circuit. After this period you are used to it and can hear through any changes to the music. You can experience the exact same effect by changing the eq slightly in a system and then listening to it for a period. My experience says people can become normalized to even relatively large eq changes.

Burn-in any way that makes you feel good. if you end up enjoying music more, then I am ALL for that. After all, you are paying for the whole process, so do what feels good to you.

I'm sure I am on some people's s#!t list now, but I'm trying to substantively contribute to the discussion by telling you the actual experience I have had.

Howie

Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
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Old 24th February 2014, 03:50 PM   #48545
PMA is offline PMA  Europe
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Some need mysteries for their business, 'burning-in' of electronic components is one of them. Or, the design is so poor that it needs an hour to heat up and stabilize.

P.S. Burn-in was the method how to find early failures of components. + thermal cycling. I do not assume guys speak about this here.
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Last edited by PMA; 24th February 2014 at 03:52 PM.
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Old 24th February 2014, 03:50 PM   #48546
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No, not me JN, you.
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Old 24th February 2014, 03:52 PM   #48547
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Isn't the Hubble a KH-11 spy satellite turned up side down, where they forgot that the curvature of the KH-11 mirror was optimized for use at less than infinity, so looking into deep space they needed a correction lens? This information is about as relevant to audio as is amplifier burn in.
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Old 24th February 2014, 03:55 PM   #48548
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hhoyt,
Thanks for that well done and carefully on your part test and conclusions of what is happening. On the speaker side you are correct, there is a change in the physical parameters of the speaker during the break-in period. micro breakage of the phenolic resins and fibers in the spider, relaxation of stresses in a molded surround and similar processes with the bending modes of the cones themselves. I would love to see someone reverse this process, it isn't going to happen without some physical change such as spraying some coating on the cone or moving parts.

Sy,
I know you were pulling our leg on the Hubble, they just forgot to change its contact lenses before they sent it up!
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Old 24th February 2014, 04:08 PM   #48549
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As I mentioned few posts above, there are scientific evidences, of various kinds, about alternating currents induced annealing of structural imperfections in solids. One needs huge efforts to develope really scientific discussion at forum with average audience, it is almost unrealistic. But at least I could enclose some scientific texts, saying about mechanisms of annealing by alternating currents and demonstrating results of measurements. The higher frequency of current - the stronger effect. Frequencies checked are from 50Hz till 200kHz. For not spending big time, I enclose the text in russian, but there are several references in the list of references, about this subject, published in english.

Here is my translation of short part from the paper:
"Efficient annealing of radiation- induced charges in the gate oxide material
and at the interface of Si-SiO2 is due to complex thermal and injection
effects of the alternating current flowing through the device structure .
Vibrational
movement of free carriers increases the probability of neutralization of trapping centers in the
insulator and at the insulator -semiconductor interface [1]. Free carriers
transfer energy to the crystal lattice and especially to defect centers with broken
bonds, causing an increase in the lattice vibrations and creation of local displacements in the lattice.
As a result, the lattice tends to occupy the state with the lowest energy."
Attached Files
File Type: pdf Defects Annealing By Alternating Currents.pdf (130.9 KB, 26 views)

Last edited by VladimirK; 24th February 2014 at 04:22 PM.
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Old 24th February 2014, 04:11 PM   #48550
SY is offline SY  United States
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Quote:
Originally Posted by vacuphile View Post
Isn't the Hubble a KH-11 spy satellite turned up side down, where they forgot that the curvature of the KH-11 mirror was optimized for use at less than infinity, so looking into deep space they needed a correction lens? This information is about as relevant to audio as is amplifier burn in.
That's what they'd like you to believe. It's actually wire burn-in that they neglected, but it's too arcane and controversial to talk about.
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