|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
73.23.122.179
In Reply to: RE: Many Times... posted by cpotl on August 18, 2015 at 10:35:41
Your mind is already made up. No problem. My experience mirrors Paul Joppa's and after some hours the sound did change. Yes, there was an improvement over the initial sound but sometimes the caps were pulled because they did not work for me in my gear.
Follow Ups:
"Your mind is already made up. No problem. My experience mirrors Paul Joppa's and after some hours the sound did change."Yes, I have reached my own conclusions. I'm not sure about your use of the word "already," though. How many years is one supposed to contemplate such matters before the "already" would be omitted?
I have observed for myself that I hear none of these alleged effects. I have considered the underlying physical principles, and I can see no reason why there should be effects of sufficient magnitude to be audible to the human ear. I have, on the other hand, read of and indeed experienced all manner of instances where the brain is deceived into thinking something happened that actually didn't, or thinking that something didn't happen that actually did.
And to cap it all, one can amuse oneself by browsing in the Tweakers' Forum, where people report (no doubt sincerely) hearing all kinds of effects due to crystals, flashing lights, blue pens, quantum fuses, or whatever that are obviously complete nonsense.
So yes, I have made up my mind. But "already"? I don't understand what you mean by that word in this context.
Chris
Edits: 08/19/15
So you think that effects in a transformer such as hysteresis saturation, eddy currents etc. are not audible as long as the bandwidth of the two transformers is the same?
I would not be surprised at all that these effects are VERY audible.
I do not have first hand experience though with changing transformers thus the reason for this thread. I do however, have experience with capacitors and that is very audible...and not always for the better.
Some guys have upgraded their AN amps (see above) as that company is firmly in the belief that better parts makes better SET amps. THey report improvements as one improves the parts...especially caps and transformers. Since I hear this clearly with caps I wondered how big a deal it is with transformers as they are usually far more expensive items in an amp (usually the most expensive part).
"So you think that effects in a transformer such as hysteresis saturation, eddy currents etc. are not audible as long as the bandwidth of the two transformers is the same?"
I would simply say that if such effects are really audible, then they will correlate with measurements that could be made, and which would shed much more light on what was going on than subjective listening reports.
The discussion in this thread has probably veered off the original topic a bit, and I think most of the recent comments have been concerned with changes in the performance of the amplifier over time (i.e. "breaking in"). The claim has been made that not only transformers, but also wire and even solder joints, need to "break in."
I don't find it totally implausible that the performance of a transformer could change over time, although I would find it much more convincing if a claim to this effect were backed up by measurements, rather than anecdotal reports of a "richer sound" or whatever. I have much more difficult believing that a connecting wire could "break in" in an audibly perceptible way.
I have no difficulty at all, however, in believing that somebody could believe that they hear an audible effect of a wire "breaking in."
Chris
"
I would simply say that if such effects are really audible, then they will correlate with measurements that could be made, and which would shed much more light on what was going on than subjective listening reports.
"
Which measurements would you propose? Hysterisis is already measureable and I would assume so are eddy currents and for sure saturation is.
BTW; Saturation shows up as a clear increase in both THD at low frequencies and with a broad spectrum of harmonics. So that one is easily measurable AND audible.
Hysterisis is measureable but its impact on the audio signal would be subtle and interesting. Reistance to changing of magnetisation polarity would impact things not easily measureable like low level signal transmission and smearing of the sound. The lower the hysterisis the more responsive the transformer will be to small changes.
Eddy currents are a known phenomenon and the whole reason that transformers are built up from thin laminations rather than solid chunks. It appears that the thinner the better. The transformers in one of my amps has 0.13mm laminations in a Double C core configuration (they weigh a good 7 or 8 Kg each). That is not the thinnest but getting close. Wire material and insulation materials also seem to matter greatly as does the winding technique. Probably this manifests itself in an increase or decrease in measureable distortion. One would have to swap in and out different trafos, with the same basic specs, made with different combinations on an otherwise identical circuit to really tell for sure.
As to break-in, you realize that as a transformer heats and cools, heats and cools, it is expanding and contracting probably by a significant amount. A SET amp in particular has substantial current running through it all the time and they warm up. Over time this will probably change the winding tension and other physical paremeters the COULD result in subtle variation in electrical behavior. Things are not as static as you would seem to believe.
"Which measurements would you propose? Hysterisis is already measureable and I would assume so are eddy currents and for sure saturation is. "I would start with measurements with oscilloscopes, spectrum analysers, etc., just in order to be sure that there actually is a real breaking-in phenomenon that needs discussing. But as I said in my last response, I don't find it totally implausible that there could be genuine breaking-in effects with transformers, for some of the reasons you have mentioned. Improbable, perhaps, but not totally implausible.
By contrast, I find it highly implausible that there could be breaking-in effects for pieces of interconnecting wire, or for solder joints. Thus I would tend to give more credence to reports of breaking-in effects for transformers. But if there are such effects, at levels that are coarse enough to be able to be sensed by the human ear, it should be easy to demonstrate the associated changes in the electrical transfer characteristics of the amplifier by means of electrical measurements. It should be possible to do better than anecdotal reports of listening impressions. There are much more precise ways of tracking changes in the transfer characteristics of an amplifier than by playing the signal through a loudspeaker and a pair of ears.
Chris
Edits: 08/20/15
"at levels that are coarse enough to be able to be sensed by the human ear,"
I think this is your gap in understanding. The human ear/brain, once trained, is a very subtle and sensitive sensor. There is plenty of evidence to support this.
Is a scope more sensitive, yes but the mistake is that the meter reader is making prejudgment on how low is too low to hear.
The problem comes with repeatability. Humans are very poor at it. A side effect of having a "wet chemistry" computer I guess. It is also trickable. It is also HIGHLY variable from individual to individual and this makes people used to instruments that are all the same crazy. It is why correlations in psychological science are poorer than in "hard' sciences like chemistry and physics where things are highly repeatable.
Up to a point, I think you are making some reasonable observations. However:"I think this is your gap in understanding. The human ear/brain, once trained, is a very subtle and sensitive sensor. There is plenty of evidence to support this.
Is a scope more sensitive, yes but the mistake is that the meter reader is making prejudgment on how low is too low to hear."I don't see a gap in understanding here. We all agree that there has to exist some threshold below which the human ear will not be able to perceive a sound. There is in fact a lot of research done on where these thresholds lie, how they change with age, etc., etc. Actually what is more relevant for the "breaking-in of components" discussion is not so much the absolute threshold of hearing, but the ability to hear a tiny change superimposed on a large background signal. And, what is more, to be able to remember how it sounded a few weeks previously, prior to the "breaking in." There can be no doubt, and I think probably you are not disputing this, that the sensitivity of precision measuring instruments exceeds the relevant thresholds of audibility.
This brings us to another key point, which you alluded to when you said "However, I don't think you or anyone else can PREDICT what the impact on sound will be because no one has done any kind of correlation study."
I absolutely agree with this, and I am always careful to distinguish between two totally different issues in discussions like this. I strongly maintain that a claim of an audible difference, resulting from some particular change of component, is logically capable of being disproved by means of electronic measuring apparatus, if it can be shown that the change in the charactersitics of the audio signal is unambiguously below any conceivable threshold of audibility. (And we don't need to descend into the kind of hopeless, helpless viewpoint of someone who says that we can't ever know anything about anything here! A lot is known and well documented about what the ear can and cannot hear.) A *totally different* question, and one that I would certainly never make any claims about, is the question of whether one could *predict* from measurements how something would actually "sound" to the listening subject. That is a much more difficult question, and one that I would not want to get into. For the present discussion, I only want to emphasise the point that sometimes one may be able to disprove an assertion about a claimed audible change by demonstrating that the change in the output from the amplifier is so much below the threshold of audibility that one can unambiguously rule out the assertion of a real, as opposed to imagined, effect. I think that the alleged "breaking in" of a solder joint would almost certainly fall in this category.
On the subject of solder joints, you said in defence of the claim that "A thin layer of oxide makes already a fairly good resistance." However, unless we are talking about a shoddy dry joint or something like that, in a properly done solder joint the oxidation would be taking place on the outside of the entire joint, and would not be interfering with the electrical flow through the joint itself.
In any case, if somebody were able to demonstrate by means of measurements that the signal voltage did indeed change significantly (i.e. above the threshold of audibility) as the solder joint broke in, then I would (obviously) have no hesitation at all in accepting that the effect would be audible. My experience, and my deductions based on order-of-magnitude estimates using standard physical principles, leads me to conclude that the effects would be way too small. Thus, when confronted with someone who claims that they do hear the effects of breaking-in of solder joints, I think it is more reasonable that I treat it with the same kind of skepticism that I have about claims that crystals sprinkled on the coffee table will affect the sound. In each case, the person reporting the effect is probably being perfectly sincere, but the explanantion for their perception is overwhelmingly more likely to be based on imagined psycho-acoustic phenomena than on actual facts.
Chris
Edits: 08/22/15 08/23/15
"but the ability to hear a tiny change superimposed on a large background signal. "
Depends on the nature of that signal. I can, for example, see a very tiny emission in a huge background if the detector is atuned to that tiny emission (perhaps you are familiar with ICP-OES for the detetction of metals?). I can detect sub parts per billion if the conditions are right. A human can tune into extremely small sound changes when it is correlated with the music. You can hear well below the actual noise floor in some cases.
"I only want to emphasise the point that sometimes one may be able to disprove an assertion about a claimed audible change by demonstrating that the change in the output from the amplifier is so much below the threshold of audibility that one can unambiguously rule out the assertion of a real, as opposed to imagined, effect. I think that the alleged "breaking in" of a solder joint would almost certainly fall in this category.
"
Fair enough but where is that unambiguous limit? And if a lot of people hear it despite the cliam it can't be possible?? Then what? Mass delusion is what you would assert?
"My experience, and my deductions based on order-of-magnitude estimates using standard physical principles, leads me to conclude that the effects would be way too small"
Maybe you are right but how are you making thes estimates? Gut feeling? How do you know what the human psyche drills in on and get's annoyed with. Haven't you ever noticed the effect that all is fine and then someone points out something to you that you never noticed before and then you find it impossible to tune it out after that (not just audio but also visual or personal)? I find in audio that when people are ignorant of certain effects they simply gloss over what we hear very easily. Once down that hole you cannot go back and "unlearn" the training. You are sensitized. Things to others that seem "trivial" or "inaudible" are no longer the case. Where are your orders of magnitude then? Is it all in their heads as some claim? I don't think so in many cases (for sure in some though).
By disclosing your education and experience, we certianly can't write you off as some weekend audio hobbyist just learning basic electronics as is often the case with these outlandish claims.
So if you want to promote the idea that 100hr old solder joints sound different than fresh solder joints we expect a properly formatted report of such phenomenon.
And we expect you to submit that report formally to the scientific community for peer review.
As for my submitting a report that there is no difference, we both know that straw man argument is void. Extraordinary claims require extraordinary proof. The ball is in your court.
If you are so sure solder joints sound different or transformers break in, that why not put your career on the line. If you do find proof, you will reap great rewards. If you don't your will be labeled a fool by your professional peers.
Go ahead, prove your claims.
So if you want to promote the idea that 100hr old solder joints sound different than fresh solder joints we expect a properly formatted report of such phenomenon.
I never said whether this is true or not. I was only commenting on how I think that break-in of transformers and capacitors is likely an audible phenomenon. I said it might be possible for soldering to also be audible on break-in but I haven't really tried to hear that myself. Given the amount of material in a transformer that can expand and contract and perhaps loosen up, it is not so far fetched to think it might affect the sound. It might also be measurable.
"And we expect you to submit that report formally to the scientific community for peer review."
WHo is we and why should I consider you my peer?
"If you do find proof, you will reap great rewards. If you don't your will be labeled a fool by your professional peers."
And i guess you would be the arbiter, right? LOL get real! I never made hard claims that for sure it happens but I took an opposing position because of your absolutist attitude that there is no way it can happen despite other experienced engineers noting the effect. You who would deny scientific method because he "knows" it can't be true...typically narrow thinking. A lot of important discoveries would pass you by because of your orthodoxy...
"And i guess you would be the arbiter, right? LOL get real! I never made hard claims that for sure it happens but I took an opposing position because of your absolutist attitude that there is no way it can happen despite other experienced engineers noting the effect. You who would deny scientific method because he "knows" it can't be true...typically narrow thinking. A lot of important discoveries would pass you by because of your orthodoxy..."That's not what I said. I said to submit your finding to the community as is done with all scientific claims. You should know that. You're right, I am not the sole arbitrator, where did I say that. If you don't consider me a peer fine, but what about the rest of the engineering community? Anyone that disagrees with you is not a peer?
FTR, I didn't say transformers don't burn in. I said there is no documented evidence I could find that such a phenomenon occurs with audio transformers. And to date nobody else here has found anything either. As for "other engineers noting the effect" where is the research documented? "Stereophile"? What are the credentials of those who have experienced this?
You seem fine with promoting FUD but when pressed to offer some data you balk.
Edits: 08/24/15
I, too, have heard components change to the better and to the worse after break-in. These are mostly subtle effects but noticeable to an astute listener with sensitive hearing.
What was the operating temperature at these different times?
How about the line voltage otherwise is the B+ stable?
Is there an RFI situation at different times of the day?
There are many more possibilities why you may have heard a difference. That's why measurements need to be made before we can assume the components are actually changing the sound by themselves based on aging.
I agree, there are many variables and would like to quantify through measurements these effects. While our measurement systems are becoming more sensitive, I do not know of one yet with the artificial intelligence logic and algorithms to replicate the selective human hearing process.
Computer technology has not advanced enough to simulate the placebo effect. To do that requires free form intelligent thought. No machine can yet do that.I don't want a machine that can do that either. I want the plain raw facts.
Edits: 08/19/15
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: