The new Synergistic Research BLUE fuses ....
Jafreeman 10-27-2017Aside perhaps for some unusual circuit configurations that may exist in a few designs, a fuse will always be in series with what it is protecting, rather than in shunt (i.e., in parallel). Otherwise the fuse wouldn’t be able to interrupt the current drawn by the equipment that is being protected, when a fault in the equipment makes that necessary. Regarding upgraded fuses being better conductors, I’ve indicated in some previous fuse-related threads that when the resistance numbers that are available for various fuse types are looked at quantitatively the bottom line generally appears to be that they are small enough to at most be marginally significant in some applications, but not in most applications. And in the case of mains fuses the voltage drops corresponding to those resistances would certainly be vastly smaller than the +/- 6 volt tolerance we have in the USA on our incoming 120 volt AC. IMO what stands a greater chance of being significant more often are the **fluctuations** in fuse resistance that occur in applications where the the amount of current being conducted by the fuse fluctuates widely. Which in turn could very conceivably result in modulation or intermodulation effects on the signal. That would apply to speaker applications (as you’ve found with your Maggies), and to many power amplifier applications. Most preamps and source components, though, draw essentially the same amount of current all the time. Nonoise 10-27-2017I recall that you’ve mentioned the statements in the first paragraph were told to you by a seller of boutique fuses. Is there any other basis that you are aware of for these statements? I am not aware of any other basis. And I can recall that at least 8 different members have reported here in the past year or two that boutique fuses blew in their equipment, which in most or all cases had presumably been operating without issue for a considerable amount of time with the stock fuses. In most of those cases the fuse which blew had the same current rating as the stock fuse, but in at least one case I can recall the upgraded fuse blew even though it had a significantly higher current rating than the stock fuse. Also, it’s perhaps relevant that the technical data supplied by Littelfuse and Cooper Bussmann for their fuses is vastly more comprehensive than data I’ve ever seen for any boutique fuse. And included in the data provided by Littelfuse and Cooper Bussmann is a melting point specification, measured in amps squared x seconds, which I’ve never seen provided for a boutique fuse. Admittedly, though, that particular spec is just provided in the form of a nominal value, without a +/- tolerance. Finally, my perception and my own experience has been that with very rare exceptions stock fuses in audio equipment tend to blow when and only when a fault in the equipment makes it necessary. So if I’m correct in interpreting the second paragraph I quoted from your post as implying that the equipment should be blamed when a boutique fuse blows and there is no evidence of an outright fault in the equipment, I would have to respectfully disagree. Best regards, -- Al |
For a means of constructing a DIY fuse cooker see the posts by Nonoise, me, and Dlcockrum dated 10-22-2017 in the Padis vs. Furutech fuse thread: https://forum.audiogon.com/discussions/padis-vs-furutech-fuses?page=2 Regards, -- Al |
Geoffkait 11-18-2017IMO the explanations that have been cited for the sonic benefits of SR and certain other boutique fuses have either involved measured differences that are much too small to account for the reported improvements (as I have explained in detail in numerous posts in various fuse-related threads here), or amount to **descriptions** of the physical characteristics of the fuse, or how it has been manufactured. A description is not an explanation. An explanation would make clear how the current being conducted by a fuse would be affected in such a manner and to such a degree that it would consistently improve the sonics of components that are completely different in design, that perform completely different functions, that are used in completely different systems, that can have either unregulated or well regulated internal power supplies, that are powered by AC having very different voltage and noise characteristics, that involve both AC and DC circuit applications, and that involve currents that do and do not vary with the dynamics of the music. I would expect that such an explanation could be provided without divulging company sensitive information. As noted above many designers are more than happy to provide comparable information. And in this case a meaningful explanation would, hopefully, satisfy many of the so-called "skeptics," and perhaps even result in a significant number of additional customers. Although I recognize the possibility that depending on the explanation the result could be the opposite. Regards, -- Al |
Tom (TheAudioTweak), thank you for your sincere, thoughtful,
and well composed explanation. What
you’ve written may be the best such attempt I have yet seen.
However, while I see no reason to dispute the possibility that it might explain the sonic benefits that have been claimed in at least a few applications, when it comes to many or most other applications it seems to me that there are some issues with it:
1)Regarding the following statement … All fuses have a solid element which is modulated by the signal that travels thru that element. Circuit breakers and my preference magnets are less prone to modulation and vibration created by the passing of signal. They will generate less interference by design or by material or both. Much of this interference in a standard fuse will be reflected back and forth along the conductor...because of the change in boundary speed and shape at either end of the element. … As I’m sure you realize, in many circuit applications fuses conduct neither a signal nor a current which varies as a function of signal. Or a current that even varies at all, aside from the repetitive and nominally sinusoidal variation within each 60 Hz AC cycle in the case of mains fuses. The current conducted by fuses in most preamplifiers, most source components, and even fuses in some power amplifiers (if they are biased in class A and provide large amounts of energy storage) has essentially zero variation from cycle to cycle. So I’m not sure that your statement has broad applicability.
2)Wouldn’t the shear wave effects you have described, to the extent they may occur in a one inch or so length of fuse wire and its associated boundaries, be completely swamped by corresponding effects in all of the rest of the wiring in the component, as well as in external wiring such as the power cord, as well as in the electrical parts in the component? As you pointed out yourself: … all the solid materials that make up any system are in a continual state of motion. The fuse element is the most simple of all the solid conductors in any audio system . Its understanding and refinement of application could be applied to all other solid materials and shapes in a sound system. 3)Most fundamentally, what leads you to conclude that the effect you have described, as it occurs in a fuse, would be great enough in degree to have audible significance with the **consistency** that has been reported, regardless of which of the extremely diverse applications I listed in my previous post is involved? In any event, thank you once again for what I consider to be an excellent attempt at an explanation. Best regards, -- Al
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In the case of SR fuses, my perception has been that the rationale for going up one or two rating increments from stock has simply been that a number of users (at least 8, as I recall) have reported in the Red Fuse thread and other fuse-related threads that SR fuses having stock current ratings blew unnecessarily. While I can only recall one instance in which someone reported that an up-rated SR fuse blew unnecessarily. That suggests, IMO, that the combinations of current and time which would cause an SR fuse to blow are more similar to those of a typical stock fuse having a somewhat lower current rating than they are to a stock fuse having the same current rating. Which is why I had said in the Red Fuse thread that IMO it makes sense to go up one or two ratings. Other opinions differed in some cases, as Nonoise pointed out earlier, and unfortunately there is room for differences of opinion because the detailed technical information that is provided by Littelfuse and Cooper Bussmann defining the blow characteristics of their fuses (nominal melting point in amperes squared x seconds, and graphs of maximum current vs. time) are not provided by SR and most or all other boutique manufacturers. With the warranty concern cited by Uberwaltz also being a consideration. Regarding PS’s questions, I suspect from the wording of his posts as well as the rating of the fuse that he is referring to a DC rail fuse, rather than a mains fuse. Which means that inrush current at turn-on probably won’t be much of a concern, if any. However it sounds like he is considering going from a 1 amp stock fuse to a 1.25 amp HiFi Tuning fuse, and I have no idea whether the rationale I cited above for going up a rating or two in the case of SR fuses would be applicable to HFT fuses. On the other hand, though, intuitively it doesn’t sound like much of a difference to me, so IMO it is a reasonable course of action. Regards, -- Al |
Geogehifi 12-22-2017Hi George, I suspect the 1 amp fuses (for which "official clearance" has been obtained to substitute fuses rated as high as 1.6 amps) are for the DC rails, not for the speaker outputs. Yesterday PS stated as follows: My mono amps are sturdy vintage MFA which have been recently highly-upgraded by one of the original designers. Each amp employs a quartet of either 6550’s or KT-88’s.Obviously amplifiers meeting that description can supply much more than 1 ampere to the speakers. While the DC rail currents would be considerably smaller than the output currents since the output transformers would step up the current supplied by the output tubes, while stepping down the voltage. Best regards, -- Al |
I have chosen not to participate in this thread until now, aside from a single post some time ago in which I responded to a factual question, because I have not felt that I have had anything of a constructive nature to contribute. However I now feel compelled to respond to the following comment: tel555 4-2-2018First, to set the record straight, Wolf has never claimed to have done any testing with Blue fuses. The lengthy report he provided about his testing some time ago, in another thread, involved SR Black fuses. More significantly, having read and participated in countless discussions over the years in which Wolf has provided inputs that have been informative, useful, and uniquely and enjoyably humorous, I for one have no doubt whatsoever as to the sincerity or honesty of his posts regarding fuses. Or regarding anything else for that matter. And, frankly, regardless of one’s beliefs about the efficacy of fuse upgrades, I consider it to be the height of arrogance for a member who has been here for only three months, and has a very minimal posting history, to provide such an insulting comment about a long-time member whose lengthy history of posts about non-fuse subjects has been widely respected and appreciated. Regards, -- Al |
It seems that it might be appropriate here for me to try to provide some answers to what I consider to be Wolfie’s legitimate question as to how fuse differences can affect sonics to an audibly significant degree. Why do I consider his question to be legitimate, and to be mostly unanswered at this point despite the countless discussions of fuse-related matters that have occurred in various threads here over the years? Four reasons:
1)Many of the purported explanations of the benefits that have been reported to be provided by expensive fuses amount to descriptions of their physical characteristics, and/or descriptions of how they were manufactured, but do not explain how those characteristics would affect the power supply circuitry and/or audio circuitry that is downstream of the fuse within the component, at least to an audibly significant degree and in a way that would be consistently beneficial.
2)Extensive sets of comparative measurements that have been provided in papers by HiFiTuning, that are sometimes cited as explanations, have been mostly debunked as explanations by me and others, such as noted amplifier designer Roger Modjeski. Generally that has been because the measured differences are far too small to account for the reported benefits, and/or are so small that they would be totally swamped by corresponding differences in the associated wiring and circuitry. (Although see item 2 below for a possible exception).
3)It is not unreasonable, IMO, to consider the high degree of consistency that has been reported for the reported benefits of SR and other expensive fuses, among components that perform completely different functions, that are completely different in design, that are used in completely different systems, that are powered by AC having very different voltage and noise characteristics, and that are used in both DC and AC applications, to simply be implausible.
4)Wolfie, as well as many of those who are on the opposite side of this issue, have earned considerable respect in my book as a result of his and their many posts here over the years.
Those are the reasons I consider Wolfie’s question to be legitimate, and to have been mostly unanswered in the past despite the lengthy discussions that have occurred, involving many of the same protagonists, in various fuse-related threads going back at least as far as the “Fuses That Matter” thread which began in 2012. At the same time, of course, I certainly recognize that many highly experienced, sincere, and knowledgeable audiophiles have reported significant benefit from these upgrades. While at least a few members having similarly high caliber audiophile credentials have tried some of these fuses and found them to provide little or no benefit, including at least one exceptionally experienced member I can think of whose system costs well north of $50K.
So from a technical standpoint what might account for the benefits that have been widely reported, and what might account for the absence of those benefits in some applications? I suspect that among the many different kinds of applications many different factors may be at play. Here is my shot at it:
1)I suspect that the effects of the small but rapid variations in fuse resistance that occur in applications in which the current through the fuse fluctuates widely are somehow affecting circuitry that is downstream of the fuse. Presumably the fluctuations in resistance differ significantly among different fuse types. I can’t explain exactly how those effects on downstream circuitry may result, though.
Circuit applications in which fuse currents fluctuate widely would include speaker fuses (even the late Peter Aczel of “The Audio Critic” recognized back in the 1980s that speaker fuses may have audible consequences), amplifier output fuses, DC rail fuses in most power amplifiers and the power amplifier sections of integrated amplifiers, and mains fuses in most power amplifiers and the power amplifier sections of integrated amplifiers, especially those not operating in class A.
2)I suspect that small differences in voltage drops resulting from small differences in resistance are probably marginally significant in at least **some** applications. For example, perhaps those differences result in audibly significant changes in the filament voltages supplied to some tubes, in designs in which those voltages are not internally regulated.
3)I would assume that the aging effects George has repeatedly referred to contribute to or are responsible for **some** of the reported benefits.
4)I would assume that improved contact integrity, scraping away of oxidation, etc., resulting from simply removing and replacing a fuse contributes to or is responsible for **some** of the reported benefits.
5)I would expect that the explanation Ralph (Atmasphere) has provided for the directionality effects that have been reported, namely reinsertion of the fuse with differing rotational orientation (rather than intrinsic directional properties), resulting in voltage drop differences which he has experimentally found to be both measurably and audibly significant (and which another member here has reported to be audibly significant), contributes to or is responsible for **some** of the reported benefits.
6)I would expect that unrecognized extraneous variables, for example differences in equipment warmup states, differences in AC voltage and noise characteristics, differences in room temperature or humidity (temperature is a fundamental parameter in the physics underlying the operation of semiconductors such as transistors, diodes, and integrated circuit chips), flushing of internal digital memory that occurs when power is cycled, etc., are responsible for **some** of the reported benefits.
Finally, given the many positive reactions to fuse upgrades that have been reported here in a multitude of diverse applications, by many (but certainly not all) of the members here who have tried them and for whom I have considerable respect, I would feel pretty certain that there are other explanations I am unaware of that are at play in some cases. Especially in the harder to explain applications in which the current being conducted by the fuse does not fluctuate significantly, and where excellent internal voltage regulation is incorporated in the design. But I have no further ideas as to what those additional explanations may be. Given though, that in the video that was recently linked to in this thread even Paul McGowan indicated that he can’t explain these benefits, I guess I’m in good company :-)
Finally, as far as my own interest or lack thereof in pursuing these things is concerned, taking into account the numerous experiences and opinions that have been reported on both sides of the issue, my own technical understanding of these matters, the numerous reports we have seen here of expensive fuses that have failed when they shouldn’t have (from at least eight different members here during the past two years), and my own general preference to devote most of my listening time to just listening to music rather than spending a lot of time trying to extract the last 10 or 20% or so of the performance my system may potentially be capable of, FWIW I personally have no plans to devote time to assessing fuse upgrades in my system in the foreseeable future. Best wishes to those who do, however.
Best regards, -- Al |
Some comments regarding Teo_Audio’s post, in which as I understand it he attributes the audible effects of fuses, at least in amplifiers, to odd order harmonic distortion which “is the distortion pattern a fuse exhibits under the highly dynamic load that a piece of audio equipment puts the fuse under.” Generally speaking harmonic distortion occurs as a result of non-linearity. And a fuse is indeed a non-linear element, in the sense that the voltage drop across it is not in linear proportion (i.e., is not in direct proportion) to the amount of current it is conducting. That follows from the fact that the fuse’s resistance changes depending on how much current it is conducting. It should be noted, though, that Teo’s explanation mentions the specific case of amplifiers. And indeed, in the case of most amplifiers the amount of current conducted by both mains fuses and fuses in internal circuitry will vary dramatically as a function of the dynamics of the audio signal. (Although in the case of mains fuses, amplifiers operating in class A are an exception to that). As I said in my lengthy previous post:
However, I don’t see how Teo’s explanation would be applicable in the case of mains fuses that are used in preamplifiers and in most source components. In those cases the current being conducted by the fuse, rather than being subject to the “highly dynamic load” Teo refers to, is essentially constant. Other questions also arise in connection with the harmonic distortion explanation. Under typical circumstances are the odd order harmonic distortion components that are referred to large enough to add significantly to the corresponding distortion components that may be present on the incoming AC, even if a power conditioner is being used? And in the case of components which provide tightly regulated DC voltages to their audio circuitry, such as most well designed preamps and source components, how would higher order odd harmonic distortion components that may be introduced by a mains fuse influence the audio signal, given that rectification (i.e., AC to DC conversion), extensive filtering, tight voltage regulation, and the typically very great “power supply rejection ratio” of the audio stages would all greatly reduce (and arguably eliminate) that influence? I’m doubtful that any of us are in a position to provide definitive answers to those questions, in part because such questions cannot be readily analyzed from a quantitative standpoint. Finally, to be sure it’s clear I am certainly not saying that fuses don’t make a difference, and I am not saying that anything in Teo’s post is incorrect. What I am saying is that the explanation he has provided for audible differences among fuses does not appear to apply to many and probably the majority of the circumstances in which benefits have been reported. Regards, -- Al |
To set the record straight, I have not said that the resistance differences between fuses that are reported in HFT’s paper are necessarily insignificant. In fact I recently said in my lengthy post in this thread dated 4-4-2018 that: I suspect that small differences in voltage drops resulting from small differences in resistance are probably marginally significant in at least **some** applications. For example, perhaps those differences result in audibly significant changes in the filament voltages supplied to some tubes, in designs in which those voltages are not internally regulated.I have also expressed the belief in that post and others that **fluctuations** in resistance, in applications where the amount of current being conducted by the fuse fluctuates significantly, might have audible consequences. Regarding **directionality,** however, in various prior fuse-related threads, such as in the SR Red fuse thread on 10-7-2016, I have stated the firm belief that: Regarding the measurements described in the HFT paper ... which purport to support the notion of fuse directionality:I have also expressed support for the explanation Ralph has provided for fuse directionality, which while recognizing the legitimacy of the experiences that have been reported does not mean that fuses have any intrinsic directional properties. Finally, regarding HFT’s measurements of thermal noise which Geoff referred to above, I said as follows in the "Fuses That Matter" thread on 5-14-2012: 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. Regards, -- Al |
I believe that the main point Mapman was making about attribution of differences that may be measured in the proposed test was simply that the measurement and comparison process should be repeated multiple times. That would presumably eliminate the possibilities that the measured differences, if any, are the result of imprecision or lack of repeatability in the test hardware and/or software itself, or are the result of extraneous variables such as differences in the warmup state of the equipment. That makes a lot of sense to me, especially when the measured differences can be expected to be small. Regards, -- Al |
Gdhal 4-18-2018Hi Hal, In addition to the possibilities Mapman cited, the rear panel of the UDP-205 is quite crowded, as you can see here. And perhaps the parts just inside the panel are crowded as well, or even more crowded. So it might not have been practical to put a fuseholder on the rear panel. Also, perhaps putting a fuseholder somewhere on the rear panel would have necessitated routing the noisy AC wiring undesirably close to sensitive internal circuitry. Design decisions usually involve tradeoffs encompassing a multitude of factors, as Mapman indicated. Best regards, -- Al |
Uberwaltz 4-20-2018+1. @mapman, in response to the query to me in your post earlier today, I can’t really add much to what I’ve said in my lengthy posts in this thread on April 4th, 6th, and 12th. I’ll emphasize one of the thoughts that I expressed in the first of those posts, though, as well as in various other fuse-related threads in the past, that what puzzles me is not the idea that a fuse can make a difference. But rather that a specific fuse would make a positive difference with the high degree of consistency that has been reported, among components that perform completely different functions; that are completely different in design; that are used in completely different systems; that are powered by AC having very different voltage and noise characteristics; that are used in DC, AC, internally regulated, and internally unregulated circuit applications; and that are used in applications in which the fuse conducts current that is essentially constant at all times as well as in applications where the current fluctuates with the dynamics of the music. Although as I said in my April 4th post it stands to reason, IMO, that **some** of the reported benefits are the result of the various factors I cited that are unrelated to the intrinsic properties of the fuse. Finally, I have no idea what the phrase "inductive quantum coupling" may mean, if anything. Best regards, -- Al |
Hi Uberwaltz, Most likely the fuse is not in the path when the DAC is powered with DC. But given the power consumption ratings stated on the specs page of the manual you could probably confirm that based on the current rating of the fuse. It would probably be in the area of 3 amps or so if it is in the DC power path, and less than 1 amp if it is in the AC power path. Best regards, -- Al |
