CD player burn in publications - are there any

Hi Folks

Not sure if this is a taboo subject here and not wanting to start a debate/arguement/fights but I have seen it debated in other places where there are obviously 2 camps, those that believe electronics burn in and those that don't. It doesn't really matter to me one way or the other but it has me interested now.

The camp that did believe in CD player (and cable, amp etc) burn in, (sound improvement with time) generally felt that evidence in terms of double blind listening experiments or other measurements etc were unnecessary, some did have experimental evidence but most thought that they believed what their ears told them and why bother with tests, what is the point of them - they noticed an improvement. Fair enough.

Those that didn't believe wanted evidence so I was wondering if there were published articles in reputable journals on this topic just to put my mind at rest. I haven't found much on the internet but surely CD player manufacturers for instance have published something?

I guess this topic becomes heated because it has other implications on the values of cables, for example, that are similarly subjectively assessed. The only double blind experiments I have seen seem to suggest that differences are hard to pick. But again, there must be properly conducted and published listening experiments as well as measurements to show that $1000/m cables are better than $2/m cables. Aren't there?

Incidentally, I thought my amp improved over the first few weeks of playing.

Richard

 

Seen it, measured it. Your amp would improve over the first few weeks.

 

Does the same thing apply to CD players and even cables (to an audible degree)?

 

In my experience, yes, and to the greatest degree with speakers

 

Certainly seen it myself with speakers and as mentioned, I thought it occurred with my amp. I guess I was hoping there may be some publications showing experimental designs and results.

 

In electronics it is mainly the capacitors which change, as Isaac will tell you. Speakers are mechanical so yes it happens with those. Cables... me not think so but lets not open that can of worms!

 

Seen what? Measured what?

Time related changes in the dielectric constant of capacitors are what I see mentioned most often. Such changes would result in a change in capacitance. Sufficient to effect an audible change or something loosely described as burn-in? That's where the speculation begins.

 

Upon buying a 2nd hand pre amp the other week I at first didn't like the way it sounded. However after several hours of listening it sounded so much better. Now it sounds great.This could partially be due to it warming up, but couldn't be down to burning in.

I think it had more down to me getting used to how it reproduced music compared to my previous unit.

That's not to say I don't believe in burn in however. It's plausible that anything with a mechanical nature will 'wear in' slightly after manufacture.

 

I have measured a change in distortion characteristic of an amplifier when the caps have "run in", and measured it's return to the original characteristic when the caps were replaced by new ones.

The mechanism is simple... Electrolytic caps rely upon the thickness of the oxide on the aluminium foil as the dielectric. This oxide grows with applied voltage and temperature. This is done in the factory.

However, once the capacitor leaves the factory, the oxide starts to break down slowly. Say that capacitor spends a year in the distribution network before being sold to the manufacturer of hifi. It's then on the shelf there for 3 months before it's put into the amplifier, and that amplifier then spends 3 months on a boat from the far east. It then sits in the retail distribution network for 3 months before spending 3 months on the dealer's shelf. That puts the capacitor at 2 years old, and in that time the oxide can thin quite a bit.

When you power up the equipment, the oxide starts to reform, as the voltage is applied and the temperature rises. This results mainly in a change to the ESR of the capacitor.

 

too many people can hear it, for it to be so easily dissmissed

If the pre has not been used for a significant period it takes time for the units caps to get back up to fully charged.....this is eaily demonstrated fit a pair of new 2uf 450v cap as dc blocker in the output stage of a cdp and then listen to the cap charge up and how the charactor of the music changes as it does so ....

if there are any blackgates in the unit ...I always feel that they revert to an unused state and need time to burn in after the unit has been removed from the mains for only a short time.

Also your dead right in that you need to get used to the sound too.

naysayer need not try as they have already formed an opinion ....

as to cables yes I've heard it but its not as consistant as some people maintain .......six identical cables only one showed any change .....???

speakers its a mechanical thing ......my bass driver took six months to getgoing [been used 5-6 hours a day from new] ...

 

Electrolytic capacitor forming, yes.

So, electrolytics need to be reformed because the oxide layer has partially dissolved or adapted to a storage voltage of zero volts? If manufacturers are selling consumer electronics with electrolytics approaching or beyond their storage life, with partially or fully dissolved oxide layers, I’d expect them to go out of business fairly quickly since out of the box reliability would be poor. There will be a period of adaptation where the oxide layer adjusts to operational voltage (having been formed at rated voltage) audible? I think reports may be somewhat exaggerated. But that’s nothing new.

 

2 years of storage does not make the device unreliable, but there is some degree of degradation over that time. It is not the case that there is no change in capacitors as they're stored until you get to their storage life at which point they're suddenly no good... it's a gradual change. The oxide reforms when the equipment is powered up, and starts to degrade again as soon as it is switched off.

The effect this has on an amplifier is measurable. Whether it's audible or not is down to each listener I suppose.

 

It's well known that electrolytics degrade and are the most ureliable type of capacitor (next to paper I believe).

 

Ah...Mosfet thought you were almost going to offer up something positive and informative !

.....just repeat "no it can't happen no its not possible" you'll soon feel more at home.

even the makers of cap offer table of life expectancy ....these show a gradual fall off in performance then onto total failure ...are they wrong too ?

 

Perhaps I wasn't clear enough Issac. Yes, electrolytics adapt over time to their operational voltage. Including zero volts when in storage. The storage life of an electrolytic describes the length of time for the oxide layer to thin sufficiently for the component to be more likely (not certain) to fail when used. This happens because the oxide layer looks less like an insulator and more like a short when a voltage is re-applied.

It's just as likely that electrolytic “burn-in†is the oxide layer thinning rather than reforming, since the process is one of adaptation to an operational voltage (which may be lower than the rated voltage used to form the capacitor).

Measurements may or may not translate into something that is audible. Given the way “burn-in†is reported I think the burn-in effect is one-part component and nine parts grey matter.

 

Try here Zanash. You'll find lots of the “informative†stuff that you like.

http://www.crank.net/

 

Indeed. There will be thin patches that grow, and thick patches that break down if the voltage in use is lower than rated voltage.

Measurement vs audability is a whole other debate. I measured changes in THD+N from 0.06% to 0.11% between well used and new caps. Whether that's audible is another matter... I only stated measureable.

I agree that there's a degree of getting used to the sound of something new also.

 

These numbers look on the high side regardless of capacitor state. What amps? And what were the capactitors doing? If the distortion degradation was at 'full' power, what was the change at a more normal output?

Interesting stuff regardless.

Paul

 

Hi again

Thanks for all the comments folks.

Also thanks for the Crank.net link.

I spent a bit of time last night trawling through the internet debates on the topic of CD player burn in and, inevitably, cable burn in and differences. I didn't make much progress in finding anything definitive and got a headache.

However, I thought these threads were entertaining.

http://forums.audioreview.com/showthread.php?t=11871
http://sound.westhost.com/cables.htm
http://www.sandman.co.nz/index.php?page=cable_nonsense.php
http://www.hometheaterhifi.com/volume_11_4/feature-article-blind-test-power-cords-12-2004.html
http://audiokarma.org/forums/archive/index.php/t-87801.html
http://www.head-fi.org/forums/showthread.php?p=2681658

Particularly liked the comments:

"I have found that it takes at least a few years to burn in electronics. The best method I have found is to leave them on 24/7 for 3 years straight. I always have something being broken in as it takes awhile . Who cares if it uses a lot of electricity and generates lots of heat. In order for this method to be viable you must not listen to the piece of equipment being burned in. You must suffer and wait the three years. That's why it's best to always be burning in a piece of equipment. As a matter of fact, I seldom listen to music as I'm so busy burning in my equipment. "

"cables require a burn-in period too. I usually just burn-in my cables along with my light bulbs (oops electronic gear). Now, more expensive cables do require a longer burn-in period than the standard 3 years, but by then I'm to eager to listen to them so I say 3 years should be adequate. Optical cables are another beast all together for they require a decade or longer in order to sound there best. Although I am on the brink of bankruptcy because of the electric bills, I can't bring myself to stop because I just know that the merchandise in burn-in just will not sound right unless its left for the full burn-in period. "

!!

There were a bunch of others I can't find but none of them really answered the question and it bacame apparent that there is unlikely to be much published and there is at least some question over double blind experiments which turn up no difference between amps, or cables, or whatever.

So, there seems to be good evidence of change in certain components within amplifiers as mentioned in this thread and in speakers (- no real debate speakers are mechanical). CD palyers and even more so cables, well one has to either believe or be labelled a "naysayer" , which seems to be audiospeak for an audio infidel.

I think I'll give up at this point and just enjoy what I have got! I did fork out on some moderately expensive cables which I'm happy with but don't want to directly compare them against my cheap nasty ones - it might burst my bubble. On the other hand, they do look more impressive on the floor between the amp and speakers!

 

think of car engines, same aplies to all electronics,specially on caps. nando