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Amp Burn-In: What actually happens?

post #1 of 108
Thread Starter 
Greetings Learned Fourm:

I am dutifully burning in my new PA2 before heading out on motorcycle trip to Nova Scotia. (kudos to Gary: Awsome amp, Awsome guy ) Can you say Road Tunes? It appears as though the sound improvement benefits of burning in an amp are beyond dispute. Yes? But as I bun, I started wondering what is actually physically happening? What occurs where and how does it open up the sound? Is that enough questions for one sentence? As always, your thoughts and opinions are greatly appreciated.

Nick B
post #2 of 108
There is really nothing physically going on. Electrons are flowing through all of the components. Burning in, is really the listener getting accustomed to the sound of their new gear.
post #3 of 108
I burned in my new computer for two weeks before I even thought about sending an email with it.
post #4 of 108
I believe in some break-in for speakers and headphones but personally, I've never heard any difference in burning-in a solid state component.
post #5 of 108
Quote:
Originally Posted by meat01
There is really nothing physically going on. Electrons are flowing through all of the components. Burning in, is really the listener getting accustomed to the sound of their new gear.
Bingo!
post #6 of 108
If you do a search (try using the terms "amp" and "burn-in"), you will find this has been discussed previously, and that the various points of view have been given (ad nauseum) in such threads, including the "it does not happen" or "it's all placebo" positions (e.g., meat01, Danamr), the "I have heard the results of burn-in myself" positions, and some actual explanations of what might be occurring electroncally. There is probably nothing more that can be said that hasn't been said previously.

I'm not trying to kill this thread necessarily or even discourage you, as I think it is an interesting question, but am perhaps suggesting that we try to focus on actual suggestions as to what might be physically happening, and critiques of such suggestions based on what is hypothesized, as opposed to more useless unsupported statements to the effect that "burn-in is a myth," "burn-in is real," etc. I assume the actual scientific explanations or hypotheses is what you wanted. If you want to hear the usual tripe (on both sides), then never mind.
post #7 of 108
In fact, things do happen electrically. As far as I know, the dielectric in capacitors oxidizes over time. Running current through the amp will de-oxidize it again (probably oversimplified). When designing an amp, the amp is voiced with the dielectrics de-oxidized so when you have a new amp with new capacitors (and oxidized dielectrics because they've been lying around in storage facilities), you won't hear the amp in the way it is supposed to sound. Now, there may be other things but this is the only one I know of and of course unless I was lied to by the CD player manufacturer. However, I find that less probable than the fact that it doesn't happen because we don't have an explanation.

Just because I don't know how something works doesn't mean it's not happening. Otherwise, a lot of things wouldn't work for me.
post #8 of 108
Quote:
Originally Posted by PhilS
If you do a search (try using the terms "amp" and "burn-in"), you will find this has been discussed previously, and that the various points of view have been given (ad nauseum) in such threads, including the "it does not happen" or "it's all placebo" positions (e.g., meat01, Danamr), the "I have heard the results of burn-in myself" positions, and some actual explanations of what might be occurring electroncally. There is probably nothing more that can be said that hasn't been said previously.

I'm not trying to kill this thread necessarily or even discourage you, as I think it is an interesting question, but am perhaps suggesting that we try to focus on actual suggestions as to what might be physically happening, and critiques of such suggestions based on what is hypothesized, as opposed to more useless unsupported statements to the effect that "burn-in is a myth," "burn-in is real," etc. I assume the actual scientific explanations or hypotheses is what you wanted. If you want to hear the usual tripe (on both sides), then never mind.
I would love to see this, too.
Quote:
In fact, things do happen electrically. As far as I know, the dielectric in capacitors oxidizes over time. Running current through the amp will de-oxidize it again (probably oversimplified). When designing an amp, the amp is voiced with the dielectrics de-oxidized so when you have a new amp with new capacitors (and oxidized dielectrics because they've been lying around in storage facilities), you won't hear the amp in the way it is supposed to sound. Now, there may be other things but this is the only one I know of and of course unless I was lied to by the CD player manufacturer. However, I find that less probable than the fact that it doesn't happen because we don't have an explanation.
According to the EE's I have asked this takes fractions of seconds, not hours or days.
Think about this: if this was true, how could you build a precision electronic measuring instrument? You could not take it out of the box and use it because it would need hours or days to "break in". There are many electronic devices that use caps have have to be very stable, yet I don't hear anyone in a physics lab worrying about a new peace of gear "breaking in". Failing, yes.
Can anyone think of any other area where people talk about "breaking in" wires with a straight face.
post #9 of 108
The magical fairy dust is activated by the electrons moving through the conductors and works to optimize the function of the circuits and parts in question.
post #10 of 108
Quote:
Originally Posted by Danamr
Think about this: if this was true, how could you build a precision electronic measuring instrument? You could not take it out of the box and use it because it would need hours or days to "break in". There are many electronic devices that use caps have have to be very stable, yet I don't hear anyone in a physics lab worrying about a new peace of gear "breaking in". Failing, yes.
Good point. I will ask the person the next time I see him about what exactly might be causing the burn-in effect.
post #11 of 108
speculation: the idea of "burning in" a solid state component was borrowed from experience with both headphones, speakers, and tube components where "burn in" is a real and significant phenomenon. the idea may not be applicable to solid state equipment, or not applicable in the same way.
the performance of solid state equipment does vary with a number of other factors with may coincide with the passage of time, thus giving the apparance of something similar to "burn in." temperature is one of these - e.g. as your computer case fills up with dust bunnies it causes the components to run hotter and hotter (and slower and slower) and eventually to stop working altogether; if you leave a flashlight in the car overnight in subzero weather, the batteries dont work very well til they warm up.
i have been told that amps with internal transformers change the way they sound as the transformer warms up and comes to an equilibrium temperature.
of course, none of this means that "burn in" is a real thing with solid state amps, but it does mean that perhaps one need not quite go looking for fairy dust.
post #12 of 108
Quote:
Originally Posted by Danamr
Think about this: if this was true, how could you build a precision electronic measuring instrument? You could not take it out of the box and use it because it would need hours or days to "break in".
Think about this, there is an implied assumption in this statement and your gneral line of reasoning that the same qualities of the amplifier components that might cause a amplifer to vary in sound are those which are critical parameters to the operation of an oscilliscope or other piece of gear. Since there is a difference in the sound of different capacitors whose electrical properties do not appear to vary, at least not in any way that would have a critical effect on the operational characteristics you mention above, there is at least some evidence that the implied assumption is not correct... Before we knew how to measure voltage or that it even existed, do you think thunder storms had lightning? Could not the same thing be true for properties of electrical devices that might have an effect on the sound?

EDIT - BTW, I have a hard time believing that amps go through a break-in every time they are run, but I sure have heard new amplifers changed because I've spent time comparing them against reference components as they burned-in and the sound varies greatly.
post #13 of 108
I believe in burn-in. I was kinda skeptical about burn-in at first, but I experienced it first hand (with headphones, not an amp yet, though I'll be getting a brand-spanking new Hornet and tell you more about my burn-in philosophy when that arrives).

My ears are very sensitive to treble. It's the first thing I notice whenever I listen to any piece in the audio chain -- headphones, amp, source, interconnects, power supply. The treble must be right for me, otherwise I won't purchase that piece of equipment even if the rest of it is stellar (ie. why I would prefer the Micro DAC over the Benchmark DAC1). When I first got my MS-1, I really liked it because the treble wasn't "too much" for me. After a few hours, the treble really opened up and got brighter.

Don't tell me that's just my ears getting adjusted to the MS-1. My ears are very sensitive to treble, and the treble opened up, and I noticed that after burn-in.

Amps probably go through a similar burn-in process. Each individual wire, capacitor, whatever has to "get loose" if you catch my drift. My ears can definitely tell an objective difference.
post #14 of 108
Manufacturers of very expensive electronics equipment put the equipment through burn-in, sometimes upwards of a week, before testing to see if it performs up to specs.
Why? Dunno. Solder settling in? Maybe. De-oxidizing as mentioned before? Probably. Thermal effects, as in the properties of components changing slightly after being exposed to high temperatures in operation? Yes.

Now, whether this makes one bit of difference in the way an amp sounds depends as much on the design and components as it does on the stars. So it may or it may not.

As for burning in computers before using them: I used to design and build equipment with custom electonics and single board rack mount computers, to be shipped overseas. We used to put them through long burn-in to see if any of the components would fail. But not because the computer worked better afterwards.
post #15 of 108
Thread Starter 
SO I GUESS IT'S SETTLED!
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