Is burn in real or placebo?
Mar 22, 2019 at 4:50 PM Post #811 of 835

upstateguy

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The basic purpose of an amp is to take a small line level signal and amplify it to be strong enough to push a transducer enough to produce sound. It really shouldn't add or subtract anything audible from the signal... it should just amplify it. They call an amp that does that "a wire with gain". There are lots and lots of solid state amps that do that perfectly. In fact, in the past 25 years or so, I haven't run across any solid state amps that aren't audibly transparent for the purposes of listening to music in the home. The best tube amps are also capable of that. If an amp succeeds as a "wire with gain", there's no reason why it should sound any different than any other audibly transparent amp.

When you talk about second order harmonics, you're talking about a different purpose altogether. In that case, you are deliberately designing an amp to NOT be audibly transparent. Some specialty amps are designed to add distortion or response imbalances to the signal in an attempt to "sweeten" the sound. For me, adjustments like that are better accomplished by digital signal processing. With a DSP, you can fine tune the coloration exactly the way you want it. With a colored tube amp, you're stuck with whatever signal distortion is hard wired into the design. That's why you see tube amp fans who have six or eight amps that they swap in and out, or they keep churning- buying and reselling amps- to try to find a perfect coloration for them. It's a LOT more efficient and inexpensive to just adjust a dial exactly the way you want it digitally. But there's a certain degree of fetishism to tube amp collecting that has nothing to do with sound quality.

Yes a tube amp can sound just as transparent as a solid state amp, and a solid state amp can sound just as distorted as a tube amp. But I don't know why anyone would go to the added trouble and expense to get a transparent tube amp when solid state ones are cheap and just as clean... and I don't know why anyone would want to buy a tube amp that is distorted with no way to adjust it.

That was really good. A candidate for another Sticky.

What comes to mind though are the Conrad Johnson Premier and the Mark Levinson ML-2 amps that were chosen for the "Challenge". They were highly regarded but each allegedly had a unique non SS sound signature which leads me to the question of transparency.
 
Mar 22, 2019 at 5:55 PM Post #813 of 835
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Going to repost this - because I believe its valid:

As far as looking for evidence =>

What we know:
  • We know speaker surrounds for dynamic drivers contain a spider which is the driver surround, and has been proven over time to "break-in" resulting in measurable changes. I don't think anyone disputes break-in affecting speakers - whether it is audible is up for debate (especially because tests are so hard to do. This is worth reading - https://hydrogenaud.io/index.php/topic,21464.0.html#entry209911
  • Most modern dynamic headphones don't have a spider (or surround) - because of the smaller drivers its simply not required. Nor do BA's or small dynamic drivers. Again the smaller drivers simply don't require it.
  • The largest manufacturer of BA based IEMs on the planet (Shure) have measured hundreds of 1000's of their own products - both BAs and dynamic, and have said that they find no evidence of audible change in their own products
  • Tyll conduced a comprehensive test of AKG's Q701 headphones, and while there were measurable differences, they were so minute as to be unlikely to be audible, and certainly not the night and day changes people claim. I suggest reading the whole article and especially the conclusion.
  • When most people claim break-in:
    • They do not volume match
    • They do not even play the same song
    • Because of auditory memory - there is no way after minutes, let along hours, they could make a valid comparison
    • The cannot precisely position the headphone of earphone in the same position to be able to even objectively make a comparison.
  • We also know that the positioning on the head of a headphone can drastically change frequency response - a multitude more than any "supposed" burn-in. For IEM's - insertion depth and angle can also drastically change canal resonance which will alter frequency response.
So what we have is a lot of anecdotal claims of burn-in, but when we go to measurements and cross-correlate that with our understandings on audibility, you'll understand why many people on this thread are so sceptical.

As far as electronic devices breaking in - we know:
  • Capacitors can alter over time. You could argue that they are at their best when straight OOTB and decline over time. Personally I find any difference so small, and my auditory memory being normal (eg human) I'd never be able to register a change. I've never seen anyone perform tests on audibility. The only way you could do it would be to record output of a track pre and post break-in, then perform an abx on the recordings.
  • Likewise tubes do change over time, and those changes can be measured. Again I haven't seen properly controlled audio tests.
 
Mar 23, 2019 at 10:41 AM Post #814 of 835

Tsukuyomi

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What makes you think that?
Well, i like to think that headphones and speakers have moving parts (drivers) that flex and move to varying degrees depending on the intensity of the music and loudness.
I've experienced myself at a friends expense a speakers driver that was pushed too hard right out of the box and the driver started to crackle and buzz and didnt sound right. apon closer examination we found out the driver had jumped out of its seating inside the speaker housing and the fabric diaphragm also ripped. the sound was terrible and required immediate repair. thank goodness my friend had the warranty still.
When we were going through the manual for the warranty card, the manufacturer did mention to not exceed a level of volume for the first 48 hours of use until the drivers have moved enough.

this concept i believe holds true to headphones as well since they do have a somewhat similar design. When I get new headphones regardless of driver design (dynamic/planar) i never push it on my source set-up past -30db for the first week. (usually within a week, 48hrs worth of music has been played, or at least i try too lol busy busy)

I'd rather gradually ease and acclimatise moving parts to use, so that they dont wear as quickly and last longer. :)

this is my thought on it.
 
Mar 23, 2019 at 11:58 AM Post #815 of 835

geek707

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Well, i like to think that headphones and speakers have moving parts (drivers) that flex and move to varying degrees depending on the intensity of the music and loudness.
I've experienced myself at a friends expense a speakers driver that was pushed too hard right out of the box and the driver started to crackle and buzz and didnt sound right. apon closer examination we found out the driver had jumped out of its seating inside the speaker housing and the fabric diaphragm also ripped. the sound was terrible and required immediate repair. thank goodness my friend had the warranty still.
When we were going through the manual for the warranty card, the manufacturer did mention to not exceed a level of volume for the first 48 hours of use until the drivers have moved enough.

this concept i believe holds true to headphones as well since they do have a somewhat similar design. When I get new headphones regardless of driver design (dynamic/planar) i never push it on my source set-up past -30db for the first week. (usually within a week, 48hrs worth of music has been played, or at least i try too lol busy busy)

I'd rather gradually ease and acclimatise moving parts to use, so that they dont wear as quickly and last longer. :)

this is my thought on it.
That is a lot of damage. It sounds like that speaker had a bad driver from the start.
 
Mar 23, 2019 at 12:44 PM Post #816 of 835

Tsukuyomi

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That is a lot of damage. It sounds like that speaker had a bad driver from the start.
Possibly, but having experienced this id rather take things slow at first with new gear and ease it into a more consistent use.
 
Mar 23, 2019 at 2:01 PM Post #817 of 835

geek707

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Possibly, but having experienced this id rather take things slow at first with new gear and ease it into a more consistent use.
To each their own.
I will observe that if it was DOA (defective out of the box), then that failure would occur if it was gently broken in or not, and by delaying the return, you are complicating the transaction with the involved retailer.
 
Mar 23, 2019 at 3:00 PM Post #818 of 835

bigshot

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I don't think that blowing a voice coil is any different on the first day as months in. If you push it to a certain point, it's going to blow. The one thing that's for sure is that whenever you do it, it's the last day for that speaker.
 
Mar 23, 2019 at 5:53 PM Post #819 of 835

Tsukuyomi

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I don't think that blowing a voice coil is any different on the first day as months in. If you push it to a certain point, it's going to blow. The one thing that's for sure is that whenever you do it, it's the last day for that speaker.
agreed,
luckily for my friend the manufacturer was excellent in assessing the issue and replacing the speaker.
 
Apr 10, 2019 at 1:38 PM Post #821 of 835

bigshot

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Oh yes! BS is MUCH more believable if you just make it into a real looking chart or diagram.

Mount-Stupid.gif
 
Apr 10, 2019 at 2:16 PM Post #823 of 835

Steve999

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Apr 10, 2019 at 3:23 PM Post #824 of 835

elmoe

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Apr 10, 2019 at 6:17 PM Post #825 of 835

bigshot

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Is a bell pepper a fruit?
 

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