Herman....Capacitors that are in frequency-sensitive circuits like a crossover, are selected to tighter tolerances, like 1%. In the usual power amplifier interstage coupling application, capacitors are specd to a much higher value than necessary so as to pass the lowest frequency of interest, so that even a 20% low item will be perfectly acceptable.
If you believe that the circuit is sensitive to exact values of components (that would not be a good design) the difference from unit to unit would be much greater than any variation of a particular unit over time and use.
And how about my question: How do the electronic components know which way to change so as to improve, rather than degrade, performance. |
Sean...I doubt that the normal changes over time/use of resistor and capacitor values can explain what you claim to hear. These changes are trivial compared with the value tolerances of the components (2% is typical for resistors and 20% is common for capacitors). Circuits are designed with such tolerances in mind. Also, if values change, why should they preferentially change in such a direction as to improve audio performance?
Now, about that 6" wire that went to 50 ohms...you know that this wasn't normal It had broken strands or the like.
If it was solid wire, and it wasn't the terminations that were bad, I hope you sent the wire to some research agency for analysis. You discovered the "Sean effect"!
There are obvious reasons for speakers and phono pickups to change with age/use, so those items ought not to be a part of this great ongoing breakin debate. |
Sean has pointed out that the change which occurs with initial use is a DETERIORATION, and he needs to readjust circuitry to make it work right. Tuned, adjustable circuits (which appear to be what he refers to) can be shifted away from optimum adjustment by the small changes of component electrical characteristics. This is not the same thing as saying that a power amplifier circuit improves with use.
The original posted question sought to find a scientific explanation for "breakin" improvement, but somehow the thread has degenerated into a debate as to whether such a thing happens. Frankly, I remain to be convinced, but my comments have been directed to pointing out that some of the theories put forward are, from an engineering perspective, obviously wrong, and detract, rather than add, to the pro-breakin point of view. |
Whatever...In the missile guidance system business we have learned over several decades that circuits ought to be configured so that they are not sensitive to exact values of their electronic components. It can be done. The necessity for items like lazer-trimmed resistors, except in particular applications like an A/D or D/A, indicates (in our experience) sloppy circuit design. Maybe that's what we have in the audio business.
So, in summary, the best explanation offered above was that of Danvetc, who suggests that the newly awakened electrons are disorganized and take a while to get together and sing "Kumbaya".
Over and out..:) Ed |
Herman, et al....My experience with audio circuitry goes back to about 1953, when we built our own equipment, often from raw electronic parts, sometimes from kits, and also did a bit of circuit design on the side. My bread and butter job, as opposed to hobby, was in the missile guidance business. (Retired now but consulting part time). Because we may disagree, don't characterize my position as inability to grasp concepts. I am familiar with all the arguments put forth above. Although some facts cited are true (eg: component values settle with use) the conclusions drawn (eg:the amp sound better) just doesn't follow. Note that I did not say that the amp didn't sound better...just that you have not correctly identified the reason. I encourage you to think up some new explanations for review.
My comments on circuit design relate to philosophy and are general in nature and applicable to most if not all types of circuitry. You might consider study of the work of Genichi Taguchi, a Japanese disciple of W Edwards Deming (the "Father of Modern Quality Control") who was very influential in the development of superior products by Japanese industry following WW2. |
Paulwp...Don't give sean a hard time! Although I don't always agree with him, I find his comments interesting/informative. Although I am primarily an academic-type engineer, I have always been known as one who likes to get his hands dirty, and I must say that some of my best theoretical insights (over a 40-plus year career) have come about as a result of screwing around in the lab.
My view in a nutshell is that things you see (or hear) in the lab ought to be confirmed by scientific expanation. Until that is accomplished, you can't be sure that you weren't fooled in some way. |
Well, I guess sean has checked out, but just as I do not discount knowledge derived from practical experience, he should not discount what's learned in college. As he says,there are no degrees granted in "common sense, problem solving, application of knowledge" but there are most certainly courses in such subjects. Indeed, many specific facts learned in school become obsolete by the time one gets a job, and the real benefit of school is that it teaches you how to learn, which you should continue to do all your life. Also, having a degree does not prevent you from doing all the things that sean does to gain knowledge.
I mentioned Taguchi design philosophy previously: very quickly here is the jist of it.
You build a circuit (or anything else, like a camera lens system) and test it.
You find that some component, say R235, critically affects performance.
It's been suggested that the circuit designer should now begin to tweek R235, and other parts of the circuit to optimize performance.
WRONG! says Taguchi. Send the circuit designer back to the drawing board to modify the design so that R235 does not need to be tweeked.
The purpose of inspection and test of samples of a product as it comes off the production line is it make sure that the design and the production process are producing satisfactory results. If a problem is found, you don't fix the unit before shipping. (That was the old idea of quality control). You junk it, and fix the design or production process. |
Sean...The design/production philosophy formalized by Taguchi is in general use throughout industry, with the exception of some very small outfits where doing it the old way is a tradition, and this may include most high end audio firms. Good performance can be achieved on a unit-by-unit basis doing things the old way. The consequence of not using the Taguchi approach is high cost, and unreliablity, and that fits high end audio pretty well.
The first example usually cited regarding Taguchi method effectiveness is the camera business in Japan. After WW2 Germany was famous as the maker of the most superb lenses and cameras. They had skilled workers who could grind lenses better than anyone else, and they kept their trade secrets to themselves. Japan realized that they could never match the skill of these workers, and so could not produce cameras comparable to the German product. So, using the Taguchi approach, they figured out which pieces of glass in the lens system were hard to make right, and they designed new lens systems that did not rely on exceptional precision of any of the elements. As a result of this effort Japan became dominant in the camera business.
Example 2 is the superiority of Sony TV sets, vs RCA, GE, Sylvania, etc. I don't think the USA manufactures any TV sets anymore. |
Unsound...We all agree that loudspeakers (and phono pickups) improve with use as the elastomers soften up.
As I mentioned, Taguchi was a disciple of W Edwards Deming, whose genius was not recognized here.
Dmitrydr...If there is a "high end" TV, it's Sony. You pay more for a Sony, and it performs better. But, they don't tweek each unit to make this happen. They tweek the design and the productiuon process so that EVERY unit that comes off the line is superior.
Everyone...How is the weather out your way? |
