Scientific Explanation for Amp Burn-In?
Apr 2, 2004 at 3:20 AM Post #2 of 30
Burn-in is like the idea of leprechauns. I don't believe in them...but they're out there.

Okay, here's one explanation. Over a certain amount of time called "burn-in", the listener grows familiar with the sound of their system. However, it's easier for people to think that their hearing is a solid reference over time and that the system changes or burns-in. The other thing to keep in mind is that everything you read about audio is true and nothing you read is false (except, of course, if you disagree with what I just wrote).

Okay, okay someone may disagree, but as I wrote this is one explanation.



JF
 
Apr 2, 2004 at 4:42 AM Post #3 of 30
I think burn-in in general is an experience caused by the following factors:
1) people being brainwashed by the new audio equipment
2) Equipment getting use to people. You should shake hands and be friends with your new audio equipment, otherwise it will continue to perform the way it left the factory instead of bending towards your will. Would you rather have those audio engineers dictate the way you listen to your stuff or would you rather have your audio equipment play it back the way you like to listen to it?

Here is the serious section: I think amps changes sonic characteristics over time. My cheap DIY amp seem to have extended frequency range and wider sound stage after like 100 hours of operation.

Some people need to warm up their amps, especially certain tube amps. If a tube breaks and needs replacing, some people say that the new tubes need to burn in before it begins to sound good.
 
Apr 2, 2004 at 4:10 PM Post #5 of 30
The leprechaun guy is on the right track.

Headphone drivers are mechanical and running them for some period of time could "work harden" the material. So there is definately some basis for change in that case, but again lots of it could be you getting used to the sound.

For amps, short of a component blowing up due to infant mortality nothing is really going to change. Now, as far as warming up goes, that's a different story and can be vital to many systems. I don't know enough about the physics of tubes, but someone could convince me there is maybe some surface change on the plates after burn in. Is it audible? Who knows. But most of the burn in game is about people thinking they hear a difference. You'll notice no one ever does a side by side comparison of the same amps, one burned-in the other factory fresh.
 
Apr 2, 2004 at 4:56 PM Post #6 of 30
How come burn in never results in a component sounding worse then when it was new? In years of reading audio forums I've never heard anyone say "I've burned in my xyz component for 100 hours and it really sucks now compared to when I first plugged it in."
 
Apr 2, 2004 at 5:29 PM Post #7 of 30
Quote:

Originally posted by mojoman
How come burn in never results in a component sounding worse then when it was new? In years of reading audio forums I've never heard anyone say "I've burned in my xyz component for 100 hours and it really sucks now compared to when I first plugged it in."


Exactly. Now, I think everyone should put together the best sounding system that they can, but focus on things that do make a difference...after electro-mechanical transducers--speakers, headphones---active components are likely to make the most difference (though of course you don't want to have shortcomings in other components of a system...). Does Sony or Sennheiser mention burn-in? A balanced perspective is necessary... And next time I have a Guinness in hand I'll double check for those leprechauns...a pint of Guinness...now there is something you can believe in... (and I don't mean the stout variety).

guinness.jpg


For anyone not twenty-one (or older), you're not missing anything... hehehe... regardless, moderation and perspective...



JF
 
Apr 2, 2004 at 6:27 PM Post #8 of 30
Burn-in on most high-end products used to take 30-45 days since credit card statements were almost exclusively mailed at that time. Now that you can check your credit card statement online, burn-in can take as little as a day.

Of course, the old school folks who shy away from computers and such, burn-in still takes 30-45 days.
smily_headphones1.gif


If you've read this far, you're obviously bored and actually seeking information so I'll share my thoughts.

Burn-in for amplifiers, sources, anything that does have moving parts usually occurs by the time all the components come up to operating temperature. At that point, all the junctions and such that may have nonlinearities in them are usually done adapting to having power on them. At that point, it's burned in.

Items that have things that move (speakers, headphone drivers, etc.) typically require a "loosening up" time to start working within specifications. Of course, distortion could be measured when it was "new" and frequency response when it was broken-in and so you could have a change in specifications. Kind of like a tire wearing out, it's going to change in sound over time.

And yes, ears to adjust to the sound around them. Try listening for a long time and slighty increase the volume every hour. Then put down the cans, sleep overnight and try to put them on the next morning. The sound will be ear-splitting.

And if you are still reading and didn't get the whole credit card statement reference, when you get a bill for an $1800 pair of speakers, they sound AWESOME the day you realize you have to pay for them.
smily_headphones1.gif
 
Apr 2, 2004 at 10:33 PM Post #10 of 30
Quote:

Originally posted by mojoman
How come burn in never results in a component sounding worse then when it was new? In years of reading audio forums I've never heard anyone say "I've burned in my xyz component for 100 hours and it really sucks now compared to when I first plugged it in."


Although I don't recall anyone in the forum saying that an amp or source sounds worse after burn-in, I have read comments about headphones sounding worse after burn-in. That's not beyond the realm of possibility since, as kwhead and ITZBITZ said, headphone drivers/transducers are mechanical and will change over time.

Back to amps for a second... I don't really subscribe to burning-in amps, but I do believe in warming them up. This is particularly important with tube amps, since you sometimes get noise through the outputs until the tubes are properly heated and the voltages bias up.

"Burn-out" (as opposed to burn-in) is definitely real, again particularly with tube amps. Worn out tubes have all sorts of symptoms, ranging from microphonics (humming, whistling, ticking, etc.) to intermittency (fading or cutting in and out).

Anyway, back on-topic... regardless of whether burn-in is a real phenomenon or just a psychological effect, some people believe that it makes a difference. It's not my business to tell them that they're wrong (or right, for that matter). If it sounds good to them, then that's fine by me.

D.
 
Apr 2, 2004 at 10:52 PM Post #11 of 30
All one has to do to test if burn-in is real is to compare a burned in unit of some piece of equipment to a brand new, never used piece. If you can detect differences in sound quality, burn in is real on that piece of gear. No real mystery here.
 
Apr 3, 2004 at 12:02 AM Post #13 of 30
Burn in is a fact, to me.

It may not be dramatic, or audible in some equipment. Low end components may not have the resolution to display an improvement with "burn in".

Some electronics are "chemical devices". Capacitors. They use material plates, but chemical (of some sort) electrolytes. Even if they are sheets of solid chemicals. Capacitors can "form", or develop characteric sound as they are used. This may take seconds, or days. Solid state devices also. I suppose you could extend this to wiring or cables too. Resistors not so much.
 
Apr 3, 2004 at 1:16 AM Post #14 of 30
Do you guys know that new equipment is not really totally new?
They are like tested for hundred of hours (in excess of 200 hours) before it gets shipped?

Atleast mine was.

If burn in is real, its a done deal when you take you new amp home.
 
Apr 3, 2004 at 2:21 AM Post #15 of 30
Quote:

How come burn in never results in a component sounding worse then when it was new? In years of reading audio forums I've never heard anyone say "I've burned in my xyz component for 100 hours and it really sucks now compared to when I first plugged it in."


Humble pie??

Hard to admit that spending 400 to 4000 dollars was a mistake. So you turn it around quick and jump on the next bandwagon??
 

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