Amp Burn-In: What actually happens? - Page 2

I DO believe that some kind of burning in of headphones may have some effect on the sonics (whether I can hear it is neither here nor there..) but this is nuts (obviously IMO !!!)

http://www.ultraaudio.com/opinion/20030801.htm

.....$1200 to "cook" cables ???

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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".'
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it's worth noting that, in fact, labs don't just take something out of the box and use it (er...i guess they have to take it out of the box sometime...) but rather anything Particularly Sensitive is kept someplace climate controlled and clean - unlike, say, my desk. also, for computers and stuff in big arrays, they are always running, so as not to vary the temperature.
there seems to be a couple major responses here: the "just cause you can't explain it doesn't mean it's not there" and the "given what we know about physics, this is not a real thing."
both are true, but "burn in" may not strictly be an artifact of the physics internal to the amp. think about moving a chair in front of a speaker or placing an FM radio (or speaker) next to an older computer monitor: things sound diferent in crucial ways, but that change in sound is not explicable simply looking at the speaker or radio.
personally, i think burn in probably doesn't happen with solid state components, but i'll perform the ritual anyway. not in the same way i might throw salt over a shoulder, but in the same way i don't walk under ladders: there is a possibility that something might fall off the ladder and onto my head; there is a possibility that the sound of the amp will change in important ways.

No, "fairy dust" is not a scientific term.

The electrons have to learn to swim better against alternating current. It takes 25 hours or more. Once trained, the electrons do fine.

With a DC (no altenating current to fight) amp the electrons can swim fine from the get go. Portables don't need any burn in.

I once saw them swim in biology class - they have little tails that wiggle.

Speakers, headphones, ok, maybe they will change. Not according to the people who make them, and electrostats, don't buy it at all, but maybe dynamics. I have a 2 hour pair of HD650's, maybe they will get better. I don't expect that, but I will look for it. I don't recall the CD3000's changing over the 4 years I have had them. But it's been a while.
Tubes......maybe. But again I am not sure why, and that would open a whole other can of worms.......like could even a unused 40+ year old tube be considered new, and how can you be sure it was never used
Sorry.
Don't buy this at all. This is right up there with magic power cords IM(not so)HO.
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Dana

Yes, you answered your own question.

That's why they burn in equipment - to test for part failure before specing and shipping.

Being an overclocker, I believe in burn-in.

http://www.ocforums.com/showthread.php?t=382751

um. "burn in" happens with speakers and headphones, or at least there is an easily identifiable physical process which would account for the phenomena called "burn in." with 'phones or speakers you are talking about a physical diaphragm which becomes less stiff as it flexes in use. this changes the sonic characteristics of the 'phone or (especially) speaker. (ever flexed a piece of construction paper (pasteboard, cardstock, whatever) back and forth? notice now it frays and gets progressively more floppy? same thing.)

look, when you are talking with people who (can) (and/or) (claim to) hear the difference between capacitors or op-amps or other solid state components, before you talk about putative SS burn in, it makes sense to at least admit the changes that do demonstrably happen with stereo equipmet over time.

i agree, probably a waste of time & money. but you've heard about freezing steel components (typically guns & knives lowered into liquid nitrogen, oxygen or something colder) to improve the characteristics of the steel, right? stupid and expensive. but, like heat tempering, it does demonstrably change the structure of the steel.
again, i'm not about to go cook my cables, but it isn't Beyond the Realm of Possibility (at least, coming from a non-technical background) that said cooking might marginally improve the cables.

(dude, what am i saying? here: i got these wicked voodoo charms... they'll make your stereo quadraphonic and orgasmic... and if you want those i got a bridge for sale...)

Unfortunately, buying it or not, it's fact. For an example that you can refer to the Black Gate Capacitor Line, although there are differences between others also. If you would like a technical explanation, it's available on the linked site and doesn't seem germane to include here. This is an example of a component that should perform identically since the electrical measurements for the critical parameters for the circuit aren't especially different, yet the sound is considerably different. Viewed in light of the simplified example of lab equipment, it should make no difference (and to the best of my knowledge it does not!).

This is not correct. I don't have a link available or time to search up the thread, but there were a group of people here who contacted Sennheiser to ask this question since there was a very persistant poster here who wouldn't believe in headphones breaking in. Actually it was the skeptic who contacted Sennheiser and recieved the reply. The answer from Sennheiser, their headphones do experience break-in as the suspension loosens up.

I can already see this thread quickly devolving into Cable Agnostics versus Cable Believers...

Probably one of the reasons for the odd, misunderstood, practice of "cable burn in" is people forget to stress it has more to do with the insulation than the wire itself... the insulation (or dielectric) stores an out of phase signal and dumps it back into the signal wire over time. How quickly or slowly depends on the dielectric constant of the insulation. A perfect vacuum is rated at a dielectric constant of 1. Teflon is about 2.1 or so. Something like PVC might be 3.6 - 4.0 - the higher the number, the more slowly the out of phase signal dumps, and more audible it will be... it might be described as time smearing. The lower the dielectric constant number (which is why many cable companies use Teflon - it has one of the lowest) the more quickly the signal dumps; it is less audible. By running signal through the wire, you are in essence charging up the insulation to its saturation point (don't forget cables are pretty much capacitors - 2 conductors separated by insulation.) I think on a smaller level, this happens with capacitors in components. Different materials take longer to fully saturate - polystyrene caps will sound very different after having signal running through them for a couple hundred hours. I find I cannot enjoy listening to interconnects or digital cables that use PVC sheathing - the notes sound smeared and phasey. Minute details like rear wall reflections and the decaying of notes get masked.

Anyway, to me, the most interesting thing would not be seeing measurements showing cable test results, but to hear the systems of various cable agnostics. THAT would be informative.

Yeah - that was a thread involving esteemed member Mike Scarpitti, a "sceptic" who conceded defeat.
IIRC, Sennheiser stated that they "burned in" headphones for 24 hrs before sending them out for review.
Much jubilation and crowing ensued - "Nah nah nah-nah nah Raspberry!!!!".
But I don't recall Sennheiser stating they burned in specifically for SQ reasons. Soak test maybe..?
Edit: yes they did - found the thread:
http://www6.head-fi.org/forums/showt...highlight=burn
Personally, I noticed a definite burn-in with my HD650s, but there you go

Hmm, despite stuff like "The Transcendent Electron Transfer" the Black Gate line has some revolutionary dielectric material (apparently), which results in lower noise, and I am speculating about the charge rise time also.
That would not be quackery - but a measurable improvement.

Exactly! If all you look at are the measured specs that are significant to the laboratory equipment, I don't believe either of those features would matter. Here is a case of us knowing what to measure but it not really being germane to normal circuit design and therefore not viewed as significant.

YOU ARE CORRECT SIR.

I'm a research scientist by profession. In the scientific community, no observation is fully valid without the appropriate controlled experiments. A simple experiment can be conducted to address the issue of whether equipment burn-in is psychoacoustic adaptation or some sort of physical (magical?) change in the equipment itself. Obtain two identical pieces of equipment. Keep one "in the box" as a control and use the other one for an extended period of time until you think it is fully "burned in." Then do a careful A/B/A listening test between the new and "burned-in" units and note any differences. One can even perform a single blind test by having a friend put a label with a code on the new and burned-in piece and having you try to identify which is which.

Of all the countless "burn-in definately improved the sound of X" experiences I've read on this forum and elsewhere, I don't think I have ever come across such a comparison. If there was such a test performed, could someone provide me a link? Of course, such tests are usually financially impractical since you would have to buy two pieces of equipment just to keep one "in the box."