Quote:
Originally Posted by Romanee
Not sure if this falls under the umbrella of your discussion, but "burn in" does not always result in positive results, so that a blanket statement that psychological acclimation is a significant (if not pervasive) reason for "growing to like" the sound of a piece of equipment would seem to fail in at least some instances.
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Your post is perhaps relevant in subject matter, but probably not argumentatively. If you re-read my post, you may note that I did not make a blanket statement and that what I did make was a statistical generalisation relatively weak to that of a blanket statement (e.g. "often" versus "always", "all cases", etc.). That doesn't mean it wasn't interesting, but I think you may have misinterpreted what I was saying in my post.
However, regarding burn-in, the phenomenon of headphone burn-in and that of something like the Hornet verges on categorically different. Headphones rely on a mechanical device that is suceptible to relatively large amounts of hysteresis in a relatively short amount of time. The level of change in your amplifier that you're describing appears to entail several decibels worth of change in distortion products and whatever else is involved in its response. While this is permissible, perhaps, in audio, this sort of performance drift is not permissible in other industries that I'm aware of, especially if it's being induced by something like the capacitors...which would seem to require very large performance shifts over a period of time very small relative to their rated stable service life. Audio is a minor industry compared to the major target industries of many of the components we use (if not all...even the AD8397, and many other op-amps en vogue today, are targeted towards ADSL line driving). As such, there is a big incentive
not to produce components that drift like this, and I can't find anything in the datasheets nor in tests I've conducted myself to suggest that this sort of drift is occurring or is expected to occur.
If you can produce for me an explanation for why one can reasonably expect such significant performance drift over the specified periods, I'd very much be interested. Ostensibly, I can't produce the explanation nor the evidence for you, so I can't carry the burden of proof for you on this one. I can, however, suggest a test that may be helpful - If you can, obtain a few Hornets, burned-in and not burned-in, and DBT (or, at least, SBT) to see if you can tell the difference between the new Hornets. Then, see if you can tell the difference between the burned-in ones, and then see if you can between the new and burned-in ones. The data obtained will hopefully help us at least make some basic (though perhaps still a bit weak) inductions about: 1. Whether there is some inconsistency in what each new Hornet sounds like, 2. Whether there is some inconsistency in what they sound like later, and 3. Whether "burn-in" is in effect. I don't have the personal resources to conduct a test like this myself and, based off of my past experience, it seems as though I'm also lacking the skill, know-how, or something else that is required to successfully replicate results such as yours with respect to burn-in.
Note - I've read that BlackGate caps do require some time for the charge barrier to form, but those places where I've read this seemed to suggest the period was much shorter than something like 300 hours. So I don't know if that can still be argued to be responsible, especially if not in the signal path.