Thesis: changes in sound are not caused by burning in of new components, it's caused by the listener's brain slowly adjusting to them.
Do you agree?
Reason for me posting this thesis are my experiences switching between headphones. I'm an avid headphones user. I've gone through several, and every time I get a new one I really hate the sound. But I always give a new one some time, and without exception I've come to like them within a week or two. IMHO this is 99% attributable to my brain slowly adjusting. In other words I think it's the brain that needs "burn-in" rather than components...
Do you agree?
Reason for me posting this thesis are my experiences switching between headphones. I'm an avid headphones user. I've gone through several, and every time I get a new one I really hate the sound. But I always give a new one some time, and without exception I've come to like them within a week or two. IMHO this is 99% attributable to my brain slowly adjusting. In other words I think it's the brain that needs "burn-in" rather than components...
Quite a few members of the Headphone forums cover their new headphones with pillows, and feed them fairly high level, but not distorted, audio from a FM tuner or similar for 48 hours or more continuously. A friend of mine did that recently with my AT W1000, which hadn't seen many hours on them, and now I am having trouble getting them back after the marked improvement. (this was from a Stax lover !)
Many years ago, quite a few Loudspeaker manufacturers advised you to slowly bed in their products,before using them at high level.
As regards semiconductors, it has been my experience, and that of quite a few other Rock Grotto members, that the metal can LM4562HA markedly improves as it approaches 48 hours of use. Many people leave their new headphone amplifiers switched on 24/7 for several days to allow the electrolytic capacitors in particular, to form, as well as some of the active devices to "burn in"
SandyK
Many years ago, quite a few Loudspeaker manufacturers advised you to slowly bed in their products,before using them at high level.
As regards semiconductors, it has been my experience, and that of quite a few other Rock Grotto members, that the metal can LM4562HA markedly improves as it approaches 48 hours of use. Many people leave their new headphone amplifiers switched on 24/7 for several days to allow the electrolytic capacitors in particular, to form, as well as some of the active devices to "burn in"
SandyK
My last headphones change was from a Sennheiser HD600 to a... uhm... Sennheiser HD600. Not really a change, you'd say. You'd be right and you'd be wrong too!
I recently ran into a new HD600 by chance and managed to knock a bit off the price by mentioning they were an old type. The HD600 I used until then had suffered serious damage from falling once too often, so this was a welcome find.
I had expected a slight difference in sound between the old and the new HD600, but it turned out to be huge. It was as big a difference going from an HD560 Ovation to my first HD600. But after a week or two it started to sound fine, as expected...
Is this break-in, adjustment of my brain or a bit of both?
I recently ran into a new HD600 by chance and managed to knock a bit off the price by mentioning they were an old type. The HD600 I used until then had suffered serious damage from falling once too often, so this was a welcome find.
I had expected a slight difference in sound between the old and the new HD600, but it turned out to be huge. It was as big a difference going from an HD560 Ovation to my first HD600. But after a week or two it started to sound fine, as expected...
Is this break-in, adjustment of my brain or a bit of both?
Jitter:
I disagree with your thesis. I'm not an engineer and cannot explain why the components I've listened to have changed over time, but there is no doubt in my mind that it is the components that have changed and not my ears adapting. Blackgate capacitors are an easy example -- they sound thin and shrill for a couple of hundred hours before settling in to a far more balanced sound. And each project with Blackgates goes through the exact same process.
This will sound self-serving, but I wrote a review of the Hagtech Frykleaner that discusses my experience: http://www.audioasylum.com/reviews/Accessory/Hagerman-Technology/FryKleaner/cables/83286.html
Now let the abuse begin.
Regards,
Scott
I disagree with your thesis. I'm not an engineer and cannot explain why the components I've listened to have changed over time, but there is no doubt in my mind that it is the components that have changed and not my ears adapting. Blackgate capacitors are an easy example -- they sound thin and shrill for a couple of hundred hours before settling in to a far more balanced sound. And each project with Blackgates goes through the exact same process.
This will sound self-serving, but I wrote a review of the Hagtech Frykleaner that discusses my experience: http://www.audioasylum.com/reviews/Accessory/Hagerman-Technology/FryKleaner/cables/83286.html
Now let the abuse begin.
Regards,
Scott
could this be anything to do with re-establishing the oxide film on the Al foil?SRMcGee said:
Have you tried pre-conditioning (re-forming using few uA of polarised current) Black Gates before fitting and compared them to off the shelf and compared them to "burnt in"?
I believe that all electrolytics degrade from manufacturing time to time of use. This may be worse for Black Gates due to the type of film/electrolyte/manufacturing process/temperature of storage/time in storage.
If you are bringing the capacitor up to specification by re-forming the di-electric then I cannot see that as "burn in". Re-forming is simply getting the capacitor to work right before you set it to use.
In transducers (involving mechanical parts) there is usually a measurable change in parameters over time and depending on thigs such as ambient temperature and humidity, but electronic components don't suffer any substantial change.
Your brain changes every day
and not necessarily for better
Your brain changes every day
and not necessarily for better 
AndrewT said:
I think that some of the electronic components vibrate themselves (ceramic caps certainly vibrate), some other components like to attain a certain thermal stasis -- the latter you can see with a THD% analyzer and a digital thermometer -- but we're talking maybe some tens of seconds.
Eva said:In transducers (involving mechanical parts) there is usually a measurable change in parameters over time and depending on thigs such as ambient temperature and humidity, but electronic components don't suffer any substantial change.
Your brain changes every day
radtech said:
Magura
jitter said:
Surely the brain adjusts to what you hear, some may even think their portable radio sound good as long as they haven't heard anything better.
Saying that, burning in of components is also real. I've tested many times by listening to a new component, then leave it to run for a week without listening and compare again. Sometimes the new component sounded worse than my reference but outperformed it afterwards. Even when directly comparing a new and a played in component show differences which disappear after the new device is also played in.
i've worked for amplifier manufacturers, and the only reason for burn-in (usually 24-48hrs) is to catch any defective parts before the amplifier goes out the door. one manufacturer i worked for actually burned in amps for 48hrs with .01uf caps plugged into the speaker jacks, and ran the amps with a 100khz input signal. since no heat is dissipated in the cap, all of the dissipation takes place in the amp, and after 48hrs running this test, the amps would generally be too hot to touch the heatsinks for more than a second or so (hotter than they would normally be running). if any components were already "on the edge", this test would catch 99.99% of them. i was there for 5 years, and i saw everything from zeners to electrolytics, to op amps, to transistors fail during ths test. bad solder joints were the most common failure that this test revealed. other common failures were mechanical (loose transistor screws, etc...). i think the OOB (out of box) failure rate was less than 0.1%, and since i did all of the warranty repairs as well, i can say i wasn't kept very busy doing that, and the amp had a 5 year warranty. i never heard of burning equipment in to get it sounding better except for tube amps, and even that one is a stretch. these aren't automobile engines that have moving parts with rough edges and tooling marks that have to be worn down to run smoothly..... the only components that change characteristics quickly enough to require "burning in" are electrolytics that have been on the shelf for a long time, and as has already been mentioned, that's a process of "re-forming" and doesn't really count as "burning-in", and with normal factory testing and burn-in, the cap is re-formed in a few hours of operating at full applied voltage.
if you want to cross-check electrolytics to see if they are in need of re-forming, all you need is a power supply that can be adjusted to the rated voltage of the cap and a resistor selected by multiplying the rated voltage x 10k. connect the cap in series with the resistor to the power supply and monitor the voltage across the resistor. the I=E/R. check the leakage current specs for the cap you have. if your current (after the cap is fully charged) is less than that value, the caps in that batch (if you bought a bag of them for instance) probably don't need re-forming. if you bought 100 of them, test 10 of them. if the caps need re-forming, keep them hooked up to the leakage test fixture for 24-48hrs (you can use more resistors to branch off and re-form them in quantity)
if you want to cross-check electrolytics to see if they are in need of re-forming, all you need is a power supply that can be adjusted to the rated voltage of the cap and a resistor selected by multiplying the rated voltage x 10k. connect the cap in series with the resistor to the power supply and monitor the voltage across the resistor. the I=E/R. check the leakage current specs for the cap you have. if your current (after the cap is fully charged) is less than that value, the caps in that batch (if you bought a bag of them for instance) probably don't need re-forming. if you bought 100 of them, test 10 of them. if the caps need re-forming, keep them hooked up to the leakage test fixture for 24-48hrs (you can use more resistors to branch off and re-form them in quantity)
My work is in industrial electronics (OEM) and some clients specify that we perform a burn-in. Usually these are high grade electronics for medical equipment or other demanding purposes. The goal is like unclejed613 said: to find the weak spots in a product that would otherwise have gone undetected and fail in a few months or so.
But that does not mean that a burn-in will have no effect on other properties of a product. My specialty at work is calibrating and testing a device used for electrochemical analyses. Think of it as a measuring amplifier that can deliver power into a load and measure what happens.
Our client performs the burn-in themselves and they told me that it does have a slight effect on things like linearity (for the worse BTW).
So I know for certain that there are physical changes after a burn-in. Yet they are so incredibly small in that device that I can't believe they would be audible in the audio range. Who's gonna hear a 0.0002 V increase in non-linearity?
But that does not mean that a burn-in will have no effect on other properties of a product. My specialty at work is calibrating and testing a device used for electrochemical analyses. Think of it as a measuring amplifier that can deliver power into a load and measure what happens.
Our client performs the burn-in themselves and they told me that it does have a slight effect on things like linearity (for the worse BTW).
So I know for certain that there are physical changes after a burn-in. Yet they are so incredibly small in that device that I can't believe they would be audible in the audio range. Who's gonna hear a 0.0002 V increase in non-linearity?
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