break-in--bane or boon ??

Roy, you've certainly been around a lot of components. What does your own experience suggest?

Thank you for your input, Charles1dad, Ivan_Nosnibor, and Nonoise. Obviously, we're of the same mind.

Mapman, I hope you'd be willing to share a soft drink at my expense at a high-end audio show in either NYC or DC next year.

Douglas_schroeder, "I would not accept hand-wired/made units made over time with possible variances in wiring, solder, caps, tubes, etc. to be close to two mass-produced units."

Douglas_schroeder, "IOW, I don't care if capactitor looks different electronically when used/broken in. I care about if the component will sound different."

Beyond overlooking my point that given the same parts, two DynaKits always converge sonically after break-in, those statements appear contradictory.

At any rate, the implication that a component employing capacitors that measure differently will not sound different flies in the face of the experience of many an audiophile, regardless of whether they believe in break-in. Even cable skeptics I talk with will often concede that if electrical properties of two cables can be differentiated, potential sonic differences could exist, even if put forth with the caveat, "the design one of the cables must be fundamentally flawed."

Regarding your question, my recollection is that the capacitor was not listened to prior to run-in, and the author's opinions on the sonics of the caps in the test followed whatever routine he used. That would fall in line with most of the capacitor write-ups I've found over the years.

Douglas_schroeder, "Don't lump me in with cable skeptics!"

Douglas_schroeder, "I'm not saying that things such as wire, caps, etc. cannot change over time. I am saying that IF they change at all the human typically cannot hear it - it is beneath the human hearing threshold."

Hopefully, you do realize that over the past three decades, the cable skeptics have parroted those very same words.

Mrtennis, "so i allow 300 hours, as a standard practice."

Given the factors in play, it sounds like the wisest strategy.

Douglas_schroeder, "To date I have had no one, professional or amateur, contest my findings. I also have found no one who has replicated the test. I suggest those who doubt my little test, who ardently belive in Burn In, get double components and do the informal testing. I can tell you what will happen; you'll not be able to hear the difference. :)"

Well, apart from Geoffkait, I will also contest your findings.

However, before going into that, I will say that the phenomena of the listener "breaking in" to the component is just as real. I myself often notice this during parts analysis, which normally devolves into a mind numbing game of waiting. Our ears surely adapt to whatever's in front of us. I absolutely believe that explains a lot of why people live comfortably with their systems, only to have another listener come away mortified after spending time with it. As both you and Al stated, perhaps the most efficacious means toward countering this remains A/B testing.

The concept of break in parallels things like wearing in a new pair of leather shoes or blue jeans. There's a period where things undergo change; the before and after states behave differently in some sort of way(s).

A few quick anecdotes:
1) Working as a chemist / material science engineer during my 20s at a company that made high technology electronic materials, I performed many experiments on the conductor, resistor, and dielectric materials we produced for the likes of NHK, Vishay, Dale, Sfernice, Roederstein, Mallory, Panasonic, Sanyo, General Motors, etc. Proving the concept of break in to a degree orders of magnitude above irrefutable, the electrical characteristics of these materials do change in large measure during the early part of their lifetime, reaching a plateau of stable operation over what's normally/hopefully a long time prior to entering their phase of age or environmental related degradation

2) A definitive objectivist, Bud Fried, who normally spent about a third of the year in Europe, and influenced a fair amount of the work at companies like Audax, Dynaudio, Focal, Kef, and ScanSpeak from the 1960s through 1990s often recounted the research and development that went on. Practical use of a new driver would produce measurable and sometimes significant change in characteristics such as Cms, Qms/Qts, and xMax

3) A friend of mine whose business is rebuilding loudspeaker drivers often tells me about how the suspension (both surround and spider) changes. He's more of the type who would never measure this sort of thing empirically, but the spider in particular offers a visual and tactile contrast one can discern

4) Some time ago, I found a coupling capacitor shootout on the web. While there are more than enough of these out there, what made this one interesting was something due to the same sort of break in argument among the folks contributing there. Perhaps to satisfy his own curiosity, the gentleman conducting the test decided to run a PC based plotting measurement on one of the caps before (new) and after some run in to see if anything along the lines of "break in" could be detected. He wound up more than surprised at the obvious degree of difference

5) To your specific challenge, I have built several DynaKit ST70 amplifiers. After completing the new unit and confirming the typical measurements, I'll replace one I've been using for a while in that system with the new amp. Though the parts are normally (though sometimes, they're not) exactly the same, the sonic differences are always both obvious and predictable. It takes a good three to four weeks of playing most days for at least a few hours for the new amplifier to catch up to an older one. The same is true, though to a lesser extent both in terms of time and sonics when I go about evaluating parts like resistors and coupling capacitors in an already established unit.

The subject of break in tracks much like cabling. Even today I meet so many audiophiles who maintain that "wire's just wire." I begrudge them not. Likewise, should you continue to go forth feeling that same way about break-in, I understand.

Douglas_schroeder, I also appreciate the discussion, thank you. I believe in such a small world, this represents the route toward best sharing the hobby.

Though I may reference your comments directly (and to others in other threads), my true intent speaks to a much wider audience. For one whose minds have already decided, I do not hold on to false hope. However, I understand that many read the forums. The aim is to not only ensure that the other side's opinions do not solely exist so that they see no counterpoint, but to spur their own curiosity and potential toward experimentation and keeping an open enough mind to try new things.

Douglas_schroder, "I believe the only way to resolve the issue is not through logic and argumentation, but by simple comparison of units."

We agree completely on that point. In fact, that's EXACTLY where I'm coming from.

The DynaKits I've built are sometimes at the same time, from the same parts bins. My experience is that one obviously will get broken in first, sound the way it should, and the sound of the second will eventually catch up once it goes through the same process.

Just a quick diversion back to objectivism. The trend through my lifetime in the realm of high-end audio has moved away from science and engineering, and toward black magic. Because of the way this business works, there's no longer enough money from sales to attract research dollars from the big companies as in the past. Over time, those who remain to manufacture this gear have less of a scientific / engineering / mathematical background than at any point in the past century, it increasingly became a cottage industry. Not to go too far down this road, but we live in a field populated by folks who have gone as far as algebra yet we require calculus in order to move to the next level. By that, I mean improvements on the level such as SACD over CD.

Douglas_schroeder, "You think I sound like a skeptic, and I think you sound like a subjectivist. :)"

Absolutely! I do admit to that willingly. My past twenty five years lie in science and engineering, so you would think I must be an objectivist, and to a large measure I am. I live in the world of mathematics, and seek out the explanation for things we hear. I don't listen to square waves, but I do know that music is a far more (orders of magnitude, actually) complex phenomena than a sine or square wave, and so the static algebraic devices that simply measure those artifacts are incapable of painting the truer picture our ears provide us with. The Scientific Method revolves around observing what makes a difference in the truest sense of the word, and right now, regardless of whether one thinks my statement sounds silly, our ears, hearts, and minds remain the best measurement devices available. As my good friend, The Doctor (Mechans) likes to say, "the proof of the pudding is in the eating." In other words, the sole aim of all of this is enjoyment of the music.

Finally, for those who need to see an example of capacitor break-in, please take a look at http://sozoamplification.com/break_in.html The article I've previously mentioned showed a much more involved and surprising trace than this via whatever computer program the author employed, but I hope that some will consider that this whole break-in thing might just involve something more than pixie dust.