04-27-12: Bryoncunningham
For the amp (Pass XA30.5), I can't tell whether the fuse is pointed downstream or not. The fuse is held into the chassis by a cylindrical fuse housing that screws into the rear panel. Anyone know if there's a typical orientation for those kinds of fuse holders? Hi Bryon, It should be possible to determine that by unplugging the amp, removing the fuse, and checking for the presence or absence of continuity between the AC hot pin on the power plug and the contact at the accessible end of the fuseholder. Best, -- Al |
04-28-12: Geoffkait
There are obviously many reasons why someone might not get the expected results, including impaired hearing, lack of listening experience, faults somewhere in the system, failure to follow instructions, etc. Thus, negative results mean precious little, except to support claims by naysayers that the device under test disobeys all known laws of science, is fraudulent, or is simply a placebo. On the other hand, positive results don't mean much either, unless: A)The assessment was conducted in a sufficiently disciplined manner, and with sufficient understanding of the variables that might affect the results, such that there can be a reasonable degree of certainty that the result is being attributed to the correct variable. For example, extraneous variables that could conceivably affect assessment of a fuse, especially one that is claimed by some to require 100 hours of breakin, would include ongoing aging, breakin, loss of breakin or rebreakin of system components; equipment being in a different state of warmup during the different parts of the comparison; differences in contact integrity resulting from removing and replacing the fuse, including scraping away of oxidation that may occur, as well as differences in contact pressure; changes in AC line voltage or noise conditions; changes in room temperature (temperature is a parameter that is fundamental to the physics of transistors and other semiconductor devices); and changes in RFI/EMI conditions. B)There is sufficient understanding of the mechanisms by which the device works, if in fact it does work, to provide confidence that its effects are not just a quirk of its interaction with the particular system, that would not occur in many or most other systems. For example, a finding that a fuse makes a difference with a Class AB or Class D amplifier, for which the AC current draw fluctuates dramatically as the volume of the music varies, IMO would say nothing about the likelihood that it would make a difference with a Class A amplifier, for which there is little fluctuation in AC current draw. C)The assessment was conducted in a sufficiently disciplined manner to rule out the possibility of misperception, placebo effect, or self-reinforcing mass hallucination (a la the stock market, ca. 2000). As a minimum, that would mean going back and forth at least a couple of times between the devices being compared, to verify that the results are repeatable. In saying that, I am not necessarily referring to an immediate ABX-type back and forth comparison, since I recognize that not all differences will be perceivable in a short-term comparison. 04-28-12: Bryoncunningham
What is the standard by which Possible Unknown Parameters are distinguished from Impossible Unknown Parameters? As with most things in life, IMO it comes down to judgment, hopefully judgment that is as informed as possible. Informed by a combination of technical understanding, experience, and inputs from others. While judgments will certainly differ considerably from person to person, it is all that we have to go on. In applying that judgment, we weigh what we consider to be the likelihood of significant benefit against the time, expense, and potential risks and downsides (see the link Clio provided) that are involved in pursuing it. FWIW, my own "a priori," subjective, and certainly fallible judgment is that the possibility of a fuse making a sonic difference falls within the realm of a Possible Unknown Parameter, while its directionality does not. In saying that, I certainly do not exclude the possibility that cables (as opposed to fuses) may have directional sensitivity, the two situations being distinguished by the vastly different lengths that are involved, by the less direct relation between a fuse and the signal path, and by the fact that many cables are asymmetrical by design (with the outer shield being grounded at only one end). Best regards, -- Al |
Hi Bryon, Sounds like you've done a good job of unearthing the kinds of explanations I'd expect to see offered for the supposed benefits of upgraded fuses. I suspect, however, that few if any of the offerings provide a quantitative perspective on the factors you listed. Re item 3, I have no idea why reducing microphonics in an AC line fuse, if indeed there are any microphonic effects to be reduced, would have any effect on sonics. All of the other items would have the effect of reducing voltage drops across the fuse or its contacts with the holder, and thereby increasing the voltage provided to the component. In the case of Class AB and Class D amplifiers, that draw widely fluctuating amounts of current, fluctuation of the voltage provided to the component would also be reduced. That sounds good until we look at it quantitatively. Here and here are data sheets for garden-variety fuses whose characteristics I believe typify the kinds of fuses that would be used in audio components. It can be seen that the higher amperage fuses, that would be used in power amplifiers, have voltage drops at maximum rated current in the rough ballpark of 0.1 volts, or slightly more in some cases. That drop would be somewhat less at the derated current levels they are presumably used at. For 1 or 2 amp fuses, such as might be used in line-level components, the voltage drops are generally a significant fraction of 1 volt at maximum rated current, and slightly more than 1 volt in one case. In the case of Class AB and Class D amplifiers, fluctuations in the voltage seen by the component that would result from fluctuations in the amount of current being drawn through the fuse would be some fraction of that 0.1 volts. Even if the upgraded fuses reduced those voltage drops and fluctuations to zero (which they won't, of course), would such small differences have any audible significance? I suspect that with some components in some systems at some line voltages there might be a marginally perceptible difference. However even if there were a difference, I don't see any reason to expect that it would be consistently in the direction of being better. Especially given that at many locations these days the AC voltage at the wall outlet is higher than the 120V or thereabouts that the components are presumably voiced at. Best, -- Al |
See this thread for a discussion of the advisability of substituting a circuit breaker for a fuse. It is not a good idea IMO. Regards, -- Al |
Hi Bryon,
As you might expect, I'm not surprised.
Among the three possible reasons that you hypothesized for the non-repeatable initial perception, btw, I suspect that reason 1 was not the cause, and it was due either to differences in contact integrity or to actions by the dog. :-)
In view of your findings, and the comment by Wrm57 on 5-1-12 as well as my technically-based comment on 4-29-12, it would be interesting if some of those who swear by the expensive fuses were to undertake a comparison between a number of different kinds of inexpensive fuses, performing the comparison in a manner such that the possibility of extraneous variables affecting the results is eliminated, per my post of 4-28-12.
Best,
-- Al |
05-06-12: Knghifi
In MF Shunyata Triton review, Caelin Gabriel invented the DTCD Analyzer that can measure anything that conducts current. He found even fuses measure differently. So theoretically fuses should sound differently in a component but like everything else, it's a function of the component. I haven't reviewed those particular measurements, but as a philosophical observation I would comment that a measurable difference by no means necessarily indicates the likelihood of a sonic difference. It depends on both the amount of the difference, and the sensitivity of the design to that difference. Every electrical part in every component has specified and/or measurable ranges of variation ("tolerances") for numerous electrical parameters, and measurable differences will exist even between two parts of the same type that were manufactured at the same time by the same manufacturer. That applies to transistors, tubes, integrated circuits, resistors, capacitors, diodes, inductors, transformers, fuses, etc. A good design will minimize or eliminate sensitivity to those differences, within the range over which they can be expected to occur. Regards, -- Al |
Why raise the point in the article if the measurements are less than tolerance level? Several reasons come to mind: 1)As I and Kijanki indicated, whether or not a given tolerance for a given parameter is sonically significant will depend on the design of the specific component in which it is used. 2)For a specific component design, a specific part, and a specific parameter, the line separating tolerances that might be sonically significant from those that are overkill will often be a gray area, about which opinions can differ. Obviously the designer of the particular component is in the best position to make those judgments (which is not to say that he or she will necessarily make them correctly). 3)Perhaps most significantly, my perception has been that it is EXTREMELY common for audio-related white papers and marketing literature to cite and describe technical differences without addressing in a meaningful way whether or not those differences are QUANTITATIVELY significant. Regards, -- Al |
Even if parts from different manufacturer that measure the same, will sound different in most cases. Agreed, of course. But that does not mean that parts which measure different in some respect will necessarily sound different, which was my initial point. As I said, it depends on the amount of the difference, and on the design of the component in which the part is used. And of course on the type of part, the function it performs in the particular design, and on what parameter is being measured. Regards, -- Al |
Thank you, Roger, for bringing the expertise of a distinguished designer to this issue. As I said in my post dated 4-29-12, the explanations that tend to be offered for the supposed benefits of expensive fuses seem plausible until they are looked at quantitatively.
Best regards,
-- Al |
Since the scope of the discussion seems to be broadening somewhat, I'll make a couple of general observations about differences that are alleged but that seem to have no rational basis, or at least no rational basis that is quantitatively supportable. First, it is commonly stated that expectations and the placebo effect can affect perceptions, both positively and negatively. That undoubtedly occurs in some cases. But my feeling is that a more significant effect may be that expectations may bias the EXPERIMENTAL METHODOLOGY in ways that lead to erroneous conclusions. In this case, specifically, it would appear that in many cases claims of substantial benefit from upgrading of fuses result from a comparison between the stock fuse and one or several expensive fuses. But if comparably intensive comparisons were performed between a number of different inexpensive fuses, what basis is there to assume that comparable benefits mightn't have been obtained at much lower cost, in the particular system? Second, I would re-emphasize what I said in my post of 4-28-12: ... positive results don't mean much either, unless:
A)The assessment was conducted in a sufficiently disciplined manner, and with sufficient understanding of the variables that might affect the results, such that there can be a reasonable degree of certainty that the result is being attributed to the correct variable.
For example, extraneous variables that could conceivably affect assessment of a fuse, especially one that is claimed by some to require 100 hours of breakin, would include ongoing aging, breakin, loss of breakin or rebreakin of system components; equipment being in a different state of warmup during the different parts of the comparison; differences in contact integrity resulting from removing and replacing the fuse, including scraping away of oxidation that may occur, as well as differences in contact pressure; changes in AC line voltage or noise conditions; changes in room temperature (temperature is a parameter that is fundamental to the physics of transistors and other semiconductor devices); and changes in RFI/EMI conditions.
B)There is sufficient understanding of the mechanisms by which the device works, if in fact it does work, to provide confidence that its effects are not just a quirk of its interaction with the particular system, that would not occur in many or most other systems.
For example, a finding that a fuse makes a difference with a Class AB or Class D amplifier, for which the AC current draw fluctuates dramatically as the volume of the music varies, IMO would say nothing about the likelihood that it would make a difference with a Class A amplifier, for which there is little fluctuation in AC current draw.
C)The assessment was conducted in a sufficiently disciplined manner to rule out the possibility of misperception, placebo effect, or self-reinforcing mass hallucination (a la the stock market, ca. 2000). As a minimum, that would mean going back and forth at least a couple of times between the devices being compared, to verify that the results are repeatable. In saying that, I am not necessarily referring to an immediate ABX-type back and forth comparison, since I recognize that not all differences will be perceivable in a short-term comparison. It is not my expectation that these factors explain all or perhaps even most seemingly implausible perceptions, but that they explain a lot of them. Regards, -- Al |
Geoff, let me pose a simple question. When a seemingly absurd claim of sonic benefit from some tweak is offered, do you consider that there can EVER be a finite limit to its apparent degree of absurdity beyond which it is justifiable to dismiss the claim "a priori"? To conjure up an example, suppose someone posts on the Internet that he has noticed that the sound of his system is significantly different depending on whether or not the TV set is on or off in the home of a friend living a mile away. He asserts that there is a cause and effect relationship between the two variables. Would you consider it unacceptable to dispute that claim without trying it? 05-12-12: Tbg
Rogermod, you suggest that hearing differences in fuses is not resistance and that maybe we should consider microphonics. Norm, that isn't what he meant. He meant that an analysis could be performed for microphonics that would show it to be comparably insignificant to resistance. Bryon, thanks very much. Coming from a person of your intellectual caliber, those are indeed meaningful compliments. Regards, -- Al |
05-12-12: Geoffkait
As a skeptic, don't you think truth would be better served by actual investigation rather that idle speculation from the comfort of your Barko Lounger? You might consider taking a tip from PT Barnum who said, folks would be better off believing in too much rather than too little. Scientific investigation and scientific progress draw upon a combination of observation, experimentation, analysis, technical understanding, and (dare I say it) reasoned judgment and common sense, among other factors. I see no reason for audio to be any different. Each individual will (and should) invest his or her time and money in ways that he or she judges to have the greatest likelihood of being productive. In making that judgment, individual experimentation, reports of experimentation by others, analysis, technical understanding, and common sense all have their place. The likelihood of optimal results from those investments of time and money will be maximized if all of those elements are drawn upon. The likelihood of optimal results from those investments will be minimized if there is an over-reliance on unchallenged anecdotal reports. Concerning your reference to me "as a skeptic," I have nowhere in this thread or elsewhere ruled out the possibility that changing fuses can make a difference. I have, though, expressed skepticism about directionality. What I have said about changing fuses can be summarized as follows: (a)The EXPLANATIONS that are offered for their purported effects do not stand up under quantitative scrutiny. (b)I suspect that a substantial number of reports of differences, but certainly not all such reports, are due either to failure to recognize and control extraneous variables, or to effects that are system dependent and do not have broad applicability to other systems, or to misperception. (c)I see no reason to expect that where a fuse upgrade makes a difference that the difference will always, or even usually, be for the better. (d)I would not be surprised if an extensive comparison of a variety of inexpensive fuses would result in differences comparable to those that are commonly reported to result from changing from stock fuses to expensive fuses. Regarding P. T. Barnum, he is often credited (perhaps incorrectly) with having made a completely different statement, that on occasion seems applicable to audio. It had something to do with birth rates. :-) Brett (Isochronism), thank you most kindly. Regards, -- Al |
05-12-12: Bryoncunningham
There's a guy over on the Polk Audio forum who claimed his measurements corroborated both that fuses measure differently and that even fuse directions measure differently. You can see his measurements here. I don't really know what to make of it. What do you think? Hi Bryon, Thanks for providing the reference, which I have read through. Looking at the larger spectral components, which are the harmonics of 60 Hz (i.e., 120, 180, 240, 300 Hz etc.) and the DC component, in most of the comparisons between different fuses and different orientations there is essentially no change. In a few cases there are some minor differences, with the expensive fuses being slightly better in some cases and slightly worse in others, compared to the stock fuses. The most notable differences occur for non-harmonic frequency components that are at levels of 60 or 65 db or so below the amplitude of the 60 Hz component. Those differences were generally in the direction of favoring the expensive fuses, but in some cases favored the stock fuses. But consider that 60 db corresponds to 0.1% in terms of voltage, and 0.0001% in terms of power. And along the lines of Roger's comment, those percentages will be GREATLY reduced by rectification, filtering, and in the case of many components voltage regulation, that occurs in the circuitry between the output side of the fuse and the signal path. I would add that the differences in those low level spectral components were so small and at such low levels that I wouldn't be surprised if they were attributable to things like differences in the amount of current being drawn through the fuses as a result of differences in the warmup state of the component, or differences in the positioning or orientation of the scope probe or its cable for each of the measurements. Mapman, thanks very much. Putting aside considerations of the specific individuals being discussed, your comment that There is such a thing as "technical intuition". This is what enables one to assess technical facts and draw conclusions that have a good chance of being accurate. strikes me as perceptive and accurate. Best, -- Al |
Hi Bryon, Just to clarify, I think that in number 3 you are referring to other fuse-related variables, perhaps unexplainable ones. Also, where I referred to rectification, filtering, and in some cases voltage regulation as reducing the magnitude of the noise components shown in the reference you provided, I should also have mentioned power supply rejection ratio. Which is to say that extraneous frequency components that may be present on the DC voltages which power the circuit stages that are directly in the signal path will not directly sum together or intermodulate with the signal. In a good design only a tiny fraction of those extraneous components will affect the signal. That is particularly the case if their frequencies are very low and therefore can't couple through stray capacitances or radiate. The noise frequencies shown in the reference you provided are of course very low. I will do my best to A/B, A/C, A/D, B/C, B/D, C/D them. It's certainly not science, but it's something. I have no doubt that your comparisons will be more thorough and disciplined than many others, and therefore more meaningful. Best, -- Al |
Hi Bryon, Thanks once again for providing the reference. I applaud HiFi-Tuning for providing these measurements. However, IMO they provide the basis for a good case as to why fuse upgrades shouldn't make a difference, or at least a difference that is necessarily for the better. In interpreting the data, btw, it should be noted that where the numbers they present that have commas separating groups of digits, the commas represent decimal points. So "24,077 milliohms" means "24.077 milliohms." Earlier comments by Roger and by me apply to the resistance and voltage drop differences that are shown on the first three pages of the reference. On 4-29-12 I said: Even if the upgraded fuses reduced those voltage drops and fluctuations to zero (which they won't, of course), would such small differences have any audible significance? I suspect that with some components in some systems at some line voltages there might be a marginally perceptible difference. However even if there were a difference, I don't see any reason to expect that it would be consistently in the direction of being better. Especially given that at many locations these days the AC voltage at the wall outlet is higher than the 120V or thereabouts that the components are presumably voiced at. On page 3 they state in reference to the resistance measurements that: There is a measurable difference in directivity of fuses. Mostly that will be due to the way the melting wire is manufactured. The difference is in the range of 5%. In fact, all or nearly all of the directional differences in resistance were vastly smaller than 5%, with the exception of the "standard glass fuse." However, even in that case, if per my comment and Roger's comments the OVERALL resistance for both directions is insignificant, the DIFFERENCE in resistance between the two orientations will certainly be insignificant. On page 4, section 3 refers to a table of vector impedance measurements, but that table and those measurements do not appear anywhere. The remaining section that presents data, section 4 beginning on page 4, opens with a statement that I certainly agree with: The measurements done so far showed some measurable differences between fuse [sic], but didn´t explain completely the sonic differences between fuses. It then goes on to present data for thermal noise, and for an increase in thermal noise. What the "increase" is with respect to is not defined, so that data is useless. And in any event the numbers shown are not large. The numbers presented for thermal noise measurements are so infinitesimal as to be laughable, being a fraction of a millionth of a volt in nearly all cases, including the standard glass fuse (on a 120 volt waveform no less, or perhaps it is even 240 volts!). A modest length of wire will pick up more noise than that from AM and FM radio signals that are passing through the air. And of course that noise level will be swamped by the noise produced by the parts and circuitry in the components, and the noise that will be present on the incoming AC (even if a power conditioner or regenerator is used). And that is all not to mention that the millionth of a volt of noise will be greatly reduced by filtering and noise rejection that will occur in the power supply and other circuitry of the component. As I said earlier, I don't exclude the possibility that a fuse change can make a difference, but once again the explanations that are offered in support of the existence of those differences do not withstand quantitative scrutiny. Best, -- Al |
Hi Bryon, A diode will conduct current when the voltage at the terminal FROM which the arrow is pointing is greater (i.e., more positive, or less negative relative to some reference point) than the voltage at the terminal TO which the arrow is pointing. (And with most diodes that difference in voltage has to be at least several tenths of a volt before significant current will flow). What makes it confusing, though, is that when conduction occurs the direction of electron flow is opposite to the direction of the arrow. That is because by convention the direction of current flow is defined as if positive charges were conducting the current (from + to -), even though electricity in metallic conductors is conducted by electrons which are negatively charged (flowing from - to +). I have no idea, though, what HiFi-Tuning intends the arrow to signify, if anything. Best, -- Al |
Geoff, I would put it that all of the technical rationale, technical data, and technical speculation that I have seen offered to explain the claimed benefits of expensive fuses, and Bryon has done a particularly noteworthy job of unearthing much of that, has been shot down on technical grounds by me, Roger, and others.
What remains is anecdotal evidence. What I have said regarding that is that I suspect that SOME (but not all) of that evidence is the result of either failure to recognize and control extraneous variables, or system dependent effects that in other systems may make either no difference or a negative difference, or misperception.
The reader can (and will) make his or her own decision as to how to proceed.
Regards,
-- Al |
05-16-12: Bryoncunningham
I found at least one amp designed by a well regarded manufacturer that includes fancy fuses: Spectron's Musician III Mk2.
Spectron's Senior Engineer, Simon Thacher, weighed in on the value of fancy fuses a while back, right here on A'gon...
It is my firm opinion that HiFi Tuning fuses are very synergistic with our amplifiers, Spectron Musician III SE. For my ears they clearly and without any question remove "gray noise" across the Spectron from high frequencies to low - making sound much more "liquid" and involving. Hmm. Just speculating, of course, but given that Class D amplifiers can be expected to have a significant amount of RF noise running around inside them as a result of the high speed switching processes that are going on, perhaps the material used to enclose the body of the HiFi-Tuning fuses lessens the amount of that noise that is picked up by the conductor within the fuse, compared to a glass body. Or perhaps the frequency content of the noise that is picked up is at least altered to some degree. That would seem kind of far-fetched, considering other opportunities that undoubtedly exist nearby for that noise to couple onto the AC wiring, but who knows? Of course, there would be no reason to expect whatever significance that kind of effect might have in a Spectron Class D amplifier to have much if any applicability to other components, especially if they are not amplifiers, and Class D amplifiers in particular. Re unplugging, if you can insert the fuse into the cap of the holder prior to inserting it into the component, and then insert the fuse + cap into the part of the holder that is mounted on the component WITHOUT TOUCHING ANY METAL on the fuse or any part of the holder, you'll be ok. If you were to first insert the fuse into the part of the holder that is mounted on the amp, intending to subsequently insert the cap over the inserted fuse, you would not necessarily escape unscathed. Re the Louis XV menu, OMG! 145 Euros for a little over 3 ounces of 2002 Leoville Las Cases, which is probably many years away from being at its peak. Makes $80 fuses seem like a bargain :-) Best, -- Al |
Kijanki, LOL! :-)
Best regards,
-- Al |
05-16-12: Almarg
Re the Louis XV menu, OMG! 145 Euros for a little over 3 ounces of 2002 Leoville Las Cases, which is probably many years away from being at its peak. Makes $80 fuses seem like a bargain :-) I should clarify that I meant it is now probably many years BEFORE it will taste its best. Best regards, -- Al |
Very nicely done, Bryon. Your disciplined and thorough methodology, and your carefully stated description of the results, in my mind makes your conclusions more persuasive than just about any other fuse comparison I can recall seeing.
And as far as the conclusions themselves are concerned, as you probably suspect I don't find anything about them to be surprising.
One piece of data that I think might be worthwhile appending to your report would be what your line voltage is, for the conditions under which you ran the tests (time of day, things turned off, etc.). While unlikely, it seems conceivable to me that if future reports by others were to include that information some sort of correlation might become apparent.
Best,
-- Al |
Nonoise, if you happen to have a multimeter can you indicate what your line voltage is, at the time of day at which you most often listen?
Also, my compliments on voicing the thought that LESSENED ability of a system/room/power source combination to reveal the sonic effects that may result from a tweak can be due to BETTER quality of the system/room/power source. That is all too often under-recognized IMO, while the inverse possibility is often cited by "believers."
As I have said in a number of past threads, countless technical reasons can be cited why a given system may be able to resolve differences between tweaks or components that have nothing to do with the ability of the system to resolve musical information. Or that may even be inversely correlated with the ability of the system to resolve musical information.
Best regards,
-- Al |
Rodman, see my comments on those measurements on page 4 of this thread, in the first of my posts dated 5-14-12.
Regards,
-- Al |
Hi Al (Rodman), I think that your points are generally well taken, and I realize that they are backed up by a great deal of relevant experience. The one point I would make in response, though, is along the lines of Kijanki's comment. It is often said that the power supply and the power source are in the signal path, and that is certainly true in a sense. However, as I'm sure you realize but others may not, the effects of power anomalies on what ultimately goes into the speakers (or at least those effects that are explainable based on generally recognized science) will be greatly reduced by filtering and smoothing that is provided in the power supply, by filtering that is (or at least should be) provided at or near all circuit points where the outputs of the power supply are used, by the power supply rejection ratio of the circuit stages that directly process the signal, and in many components by voltage regulator devices and circuits. I think that a good indicator of the significance of the distinction between being directly in the signal path, and being indirectly/in a sense/sort of in the signal path, is that if this thread were about fuses that are in speakers, or fuses that are in amplifiers in series with their outputs, I suspect that it would have ended about 300 posts ago, with little or no controversy. I, and I suspect most technically-oriented fuse skeptics, would consider it highly surprising if there were NOT significant sonic differences between fuses in those applications. Best regards, -- Al |
It probably goes without saying, but I'll say anyway that I am in total agreement with what I consider to be Bryon's exceptionally incisive, precise, and clear analyses and comments.
Furthermore, I consider his finding of sonic differences between the fuses he has tried to be more persuasive than most such claims, given his careful and thorough methodology, his clearly unbiased and open-minded approach, and his precise description and qualification of the results.
On another note:
1)If indeed AC line fuses in audio components can result in perceptible sonic differences, and
2)Given that parties on both sides of the issue (me and TBG, for example) mutually recognize that those differences defy technical explanation and understanding, and
3)Given that most and perhaps nearly all reported fuse comparisons seem to be between the stock fuse and one or more expensive fuses,
what basis is there to assume that a comparison among a variety of INEXPENSIVE garden-variety fuses would not result in a perception of comparable differences, with the winner of the comparison perhaps being subjectively as good as any of the expensive fuses? I see no such basis or rationale from a technical standpoint, and I see no such basis in any of the nearly 400 posts that have appeared in this thread so far.
Bryon's finding that the stock fuse was preferred in two different components to one of the expensive fuses that were tried gives added legitimacy to that question.
Personally, I have no interest in taking the time to perform that experiment. But would one of those who has advocated the superiority of expensive fuses vs. stock fuses care to give it a try?
Regards,
-- Al |
Tom, I'm not sure that I understand your last two posts, but I believe that the implication of what you are saying is that any effects of the AC line fuse on the current flowing through it will be directly and identically reflected in the current that is sent out to the speakers. If that is what you mean, I would beg to differ. As I said in my post dated 5-31-12: ... the effects of power anomalies on what ultimately goes into the speakers (or at least those effects that are explainable based on generally recognized science) will be greatly reduced by filtering and smoothing that is provided in the power supply, by filtering that is (or at least should be) provided at or near all circuit points where the outputs of the power supply are used, by the power supply rejection ratio of the circuit stages that directly process the signal, and in many components by voltage regulator devices and circuits. Also, the visual differences that you observed on the RTA do not necessarily imply audible significance, especially if all frequencies are affected equally (for example, if a gain change resulted from a slight difference in the voltage drops across the fuses), and of course depending also on the magnitude of the differences. Regards, -- Al |
07-23-12: Nonoise
There is enough anecdotal evidence around for any naysayer who hasn't tried a high end fuse to readily accept the fact that we do hear a difference. True. But, as I suggested earlier, how do we know that comparable differences would not occur if an extensive and thorough comparison were performed among several different inexpensive garden-variety fuses? Especially given that the technical explanations for the alleged benefits of expensive fuses are not well established, at least in a manner that withstands quantitative scrutiny, as I indicated in some of my earlier posts in this thread. There would seem to be no significant anecdotal evidence regarding that possibility. And note that in the meticulous and disciplined comparison that was performed by Bryon, who IMO is one of our most credible, intelligent, and open-minded members, the stock fuse was found to be preferable to one of the expensive fuses. Best regards, -- Al |
09-08-12: Audioman58
The main reason why a aftermarket fuse makes it oundstaging better is a easy explanation .a stock Steel fuse has 7-8 Times the resistance of Silver. Just check the resistance index online.as we all know resistance in electronics is a Huge bottle neck for everything goes through them.
First, let me say that I don't question the sonic improvements you obtained from your fuse upgrades. Second, let me say that your explanation is one that initially may seem logical. However, IMO the explanation does not stand up when looked at quantitatively, for several reasons. Before going into those reasons, let me say that resistance in a fuse can have two effects: (a)The voltage seen by the component will be reduced from the voltage that is provided at the wall outlet (or the outlet of a power conditioner or regenerator, if present). That reduction will equal the voltage dropped across the fuse, which in turn will correspond to the amount of current being conducted through the fuse multiplied by the resistance the fuse has at that current level. (b)If the amount of current drawn by the component fluctuates significantly, the voltage seen by the component will also fluctuate, to a degree corresponding to the DIFFERENCE between fuse resistance x current draw when the current draw by the component is at a maximum, and fuse resistance x current draw when the current draw is at a minimum. If you examine the very extensive test data on various fuses that is provided by HiFi-Tuning, that was linked to by BryonCunningham earlier in this thread, you will see that the resistances of the standard glass and standard ceramic fuses that were tested were such that when carrying amounts of current within the range they are intended to carry the voltage drops across them were a small fraction of a volt, in most cases a tiny fraction of a volt. That leads to the following conclusions: 1)In components that draw relatively constant amounts of current, and/or that have regulated power supplies, the effects of that small fraction of a volt reduction of the AC line voltage seen by the component will be utterly negligible. That would apply to your DAC-Preamp, to nearly all other preamps and source components, and to Class A amplifiers. And lest there be any doubt about that, see the next item: 2)EVEN IF that small fraction of a volt reduction of the AC line voltage seen by those components has any audible significance, minimization of that reduction by a fuse having lower resistance would NOT BE CONSISTENTLY FOR THE BETTER. Suppose for instance that a component is designed such that it works best at 120VAC. If the AC line voltage at the particular location is less than 120 VAC, the slight increase in voltage provided by the upgraded fuse would be in the direction of helping. But if the AC line voltage at the particular location is greater than 120 VAC, the increase would be in the wrong direction, and would degrade sonics if in fact it makes any difference at all. 3)With a component that has an unregulated power supply and draws widely fluctuating amounts of current, such as most Class AB power amplifiers, the FLUCTUATION in voltage drop across the fuse could, if great enough, have sonic consequences. Again, however, it would seem highly farfetched that further reducing what would be a tiny fraction of a volt of fluctuation with a standard fuse would produce significant and consistent improvements among different amplifier designs. And,again, even if there were a benefit in those cases, it would not be applicable to other kinds of components. Regards, -- Al |
A P.S. to my previous post. Obviously I was addressing AC line fuses, and fuses that are conducting audio or other signals, in speakers or at circuit points within electronic components, may be a completely different story.
Regards,
-- Al |
Hi Dover, I'd imagine that improved contact integrity resulting from merely changing the fuse is the explanation is some cases, but not in many others. I can't see how noise pickup could be an explanation, considering the short length that is involved, the much greater length of the associated wiring (both internally and externally to the component), the considerable amounts of noise that are presumably present on the incoming AC, the noise rejection provided by the power supply, and the noise rejection resulting from the power supply rejection ratio of the circuit stages in the component. Better materials and construction are often cited as an explanation, but IMO that is a non-explanation, because it doesn't explain (in a quantitative manner, if at all) why the supposedly inferior materials and construction of the standard fuses would degrade the sound. As you may have seen earlier in this thread, e.g. in the first of my posts dated 5-14-12, and also in the post by Rogermod (the distinguished amplifier designer Roger Modjeski) dated 5-11-12, pretty much all of the other commonly offered explanations do not stand up when analyzed quantitatively, at least for AC line fuse applications. A point I made earlier in the thread is that all of the comparisons that are reported seem to be between the stock fuse and one or more expensive fuses. But without a good understanding of the reasons for the sonic differences that are claimed, how do we know that a thorough comparison between a variety of ordinary fuses wouldn't result in comparable differences? Perhaps sonic differences would even be found between multiple examples of supposedly identical fuses. Best regards, -- Al |
+1 to Metralla's comment.
Vance, I'm not certain that the Classe person you spoke to was giving you a precise answer. Breaking capacity (also referred to as "interrupting rating") has nothing to do with the likelihood that inrush current at turn-on will cause unnecessary fuse blows. Or, at least, there is no direct relation between the two.
Breaking capacity refers to the maximum amount of current occurring under fault conditions, when the fuse SHOULD blow, that the fuse can deal with without an explosion or other safety hazard occurring. That rating will be far greater than the current rating of the fuse.
The parameter that is most relevant to withstanding inrush current without blowing unnecessarily is what is called the "nominal melting" point of the fuse, which is usually specified as (amps squared) x (seconds).
Datasheets at the Littelfuse site provide very comprehensive technical data on their fuses. You might want to look up the specs for the particular fuse that is in your amplifier, and ask the manufacturer of the upgraded fuse you are considering if they can provide you with the nominal melting spec for their fuse (as well as its breaking capacity, which as I said is relevant to safety). Their response should be interesting.
Regards,
-- Al |
Thanks, Vance. Here is the datasheet. (I assume you meant 5 x 20 mm, not 5 x 22). Looks like the breaking capacity/interrupting rating (related, as I said, to assuring that blowing which occurs under fault conditions occurs in a safe manner) is spec'd as 1500 amps @ 250 volts, and the nominal melting spec (related to the likelihood of unnecessary blowing at turn-on) is 515.5 amps squared-seconds. Regards, -- Al |
Hi Vance,
I don't doubt that these companies COULD replicate the protection characteristics of the stock fuse. However, different designs of just about any electronic product differ in terms of their design goals and philosophies, and how the tradeoffs that inevitably must be made between many different parameters are prioritized.
As you've seen in the datasheet, even something as simple as a fuse has a great many different specifiable parameters. In addition, earlier in this thread links were provided to papers prepared by HiFiTuning which presented several pages of comparisons between various measurements of various makes of fuses. The data differed widely among the different fuses. (Although I commented that IMO none of the differences appeared likely to be quantitatively significant, and even if some of them were quantitatively significant in some applications, I saw no reason to expect the resulting sonic effects to be consistent among different component designs, and among different AC line voltages).
So given the many parameters that are involved, and the diversity of measured data for different fuses having similar current ratings, it seems to me that while the aftermarket fuse manufacturers COULD replicate the protection characteristics of this particular Littelfuse, I would have my doubts that they DO closely replicate them. But as we said earlier, it will be interesting to see what they provide in response to an inquiry asking for breaking capacity and nominal melting numbers.
Here's another thought, though, that is suggested by the numbers in the Littelfuse datasheet. On the first page, take a look at the numbers in the table of "opening times" (i.e., the amount of time required to blow) that are shown at the lower right. Note in the entries for 275%, 400%, and 1000% that the range of specified opening times for a given fuse and a given overload is huge. For example, for fuses rated between 8 and 20 amps, and overloaded to 400% of their rating, the blow time can be anywhere from 0.15 seconds to 5 seconds. That is a huge possible variation from fuse to fuse. Which suggests the likelihood that many other parameters, for which only a nominal value and not a range of possible values are specified, could also have wide fuse-to-fuse variations.
So it seems to me that a useful experiment may be to simply buy a bunch of fuses that are the same make and model as the stock Littelfuse, and compare sonics between them. Who knows, maybe you'll find significant sonic differences between them, and perhaps one or more of them will provide sonics comparable to what the aftermarket fuses would provide.
If you do that, btw, it might be best to split the order among multiple distributors (e.g., Digikey, Mouser, Newark, etc.), which may increase the likelihood that the fuses you try come from different production runs.
Regards,
-- Al
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Simply put, replacing a slow blow with a fast blow risks "nuisance" (unnecessary) blows, while replacing a fast blow with a slow blow risks extensive damage to the equipment (and conceivably even the possibility of a fire) if a fault were to occur.
A substantial change in the "nominal melting" (amps squared-seconds) parameter of a fuse, which would result from a change between fast and slow blow types, amounts to a design change in the equipment, which should not be done without careful analysis. And the information about the design that would be necessary to do that analysis will generally be unavailable to the end user.
Regards,
-- Al |
