DAP Burn-In - What happened?
Nov 26, 2018 at 11:00 AM Thread Starter Post #1 of 10

ThomasCGN

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Hey,

I’m well aware, that the question wether Burn-In for DAPs is real or not is heavily debated already. This post ain’t about that! It’s rather a scientific one:

When I got my latest DAP (AK SR15) I couldn’t help but give it a go right out of the box. I was surprised to find spaciousness was a little bit short compared to my AK70 and heights seemed to be inelegant and sharp at times. I then connected Headphones and let it play for three days straight without ever listening to it. Afterwards I compared again and the soundstage seemed to have widened and treble definition was both smoother and more detailed as in my AK70. So: Call me a believer. Burn-In did something to the player.

But call me also a physicist, wanting to know! What exactly happened there?
I honestly have trouble thinking of something.
 
Nov 26, 2018 at 4:12 PM Post #2 of 10

tomb

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Burn-in is real in electronic circuits, particularly when electrolytic or film capacitors are involved. However, in all the things that I've built, the noticeable changes really occur in a matter of hours - not three days or longer. It takes a definite time period for capacitors to fully form (or re-form after storage without exposure to voltage). In the case of electrolytics, there's an actual slurry mixture that reacts to a voltage being applied. Along with the electrolyte, an applied voltage will work to "form" and/or "re-form" the oxidized layer on the aluminum foil (inside) that forms the capacitor's dielectric. Some people claim this occurs instantaneously or that the capacitors are fully formed when shipped from the factory. In my experience, that's not really true.
 
Nov 26, 2018 at 10:03 PM Post #3 of 10

muschem

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I haven't read much about the particulars of burn-in... only that it is apparently "a thing". Is load supposed to matter? By that I mean, would it be equally effective to run source without drivers attached, or should there be some impedance present for this to work well? Sorry if this is an "asked and answered" sort of thing.
 
Nov 26, 2018 at 10:55 PM Post #4 of 10

Mhog55

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I was never a believer myself, and I agree with the above post. Whatever burn in occurs, will be fully resolved within a days time. My new V40 sounded ugly out of the gate. Let it play overnight, and now it sounds more like what I'm familiar with.
 
Nov 27, 2018 at 12:23 AM Post #5 of 10

ThomasCGN

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Thank you for your replies.

If I understood you correctly Burn-In is a mechanical phenomena, in the end. As you described it ascribes to the electrolytes slurry distributing evenly and forming an even alluminum foil layer. Comperably few (I would suppose only the ones after the DAC can constribute) and small (after all, used current is very low) capacitators are responsible for the shift in sound?

I still have three follow up questions, though:
- is that it?
- how? I can imagine, that capacitors “formed” might experience less chaotic fields when being charged. But would that be enough?
- why? Manufacturers are likely to lose millions due to people testing audio equipment for 10minutes and then deciding against it. Why don’t they burn in their capacitors before? It would be incredible easy and cheap?

Thanks a lot

P.s. I do not understand the science fully here. But yes: If it comes down to current forming capacitors, then (little) load is essential.
 
Nov 27, 2018 at 12:45 AM Post #6 of 10

PointyFox

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Could have had some inner-ear pressure or some swelling, possibly due to allergies, which caused you to hear a little differently when you first listened. I've only seen evidence disproving audible burn-in.
 
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Nov 27, 2018 at 2:10 AM Post #7 of 10

ThomasCGN

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Could have had some inner-ear pressure or some swelling, possibly due to allergies, which caused you to hear a little differently when you first listened. I've only seen evidence disproving audible burn-in.

Please be reminded of my initial post.
a) I did an A/B both times. So am ruling out ear pressure.
b) I asked about technical reasons or musings for digital equipment changing sound signature over time. I explicitly did rule out a discussion on the “If” as they are broadly discussed already. In these discussions scientific sources are scarce for both positions. And if you have many of them it might help to contribute there.
c) Please abstain from making any medical assumptions about me. It feels awkward if someone I never met is proposing a medical reason to argue a misconception I made that he/she did not witness.
 
Nov 27, 2018 at 2:26 AM Post #8 of 10

yong_shun

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Nov 27, 2018 at 3:20 AM Post #9 of 10

ThomasCGN

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Nov 27, 2018 at 8:54 AM Post #10 of 10

PointyFox

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Please be reminded of my initial post.
a) I did an A/B both times. So am ruling out ear pressure.
b) I asked about technical reasons or musings for digital equipment changing sound signature over time. I explicitly did rule out a discussion on the “If” as they are broadly discussed already. In these discussions scientific sources are scarce for both positions. And if you have many of them it might help to contribute there.
c) Please abstain from making any medical assumptions about me. It feels awkward if someone I never met is proposing a medical reason to argue a misconception I made that he/she did not witness.

a) You didn't mention A/B testing in your initial post.
b) Physiology IS a technical reason why DAPs may seem to change over time.
c) You're weird. I just mentioned allergies.
 

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