Aolmrd1241 4-7-2016 9:46am EDT
I read somewhere that only the direction of the ac [in a fuse...or power cord for that matter] towards the business end of the component[what is heard] is of any value in directional break-in ,hence, the reason there is directionality in a fuse used in an ac circuit is because of the cycle going to... and not fro. For what its worth,it sounds plausible. While it is true that in the case of an AC mains connection energy is being transferred essentially in just one direction, from the outlet to the component, a fuse in that path has no way of being aware of that direction. All it has knowledge of is the current flowing through it. It is not even aware of the voltage of the AC, unless it is blown or in the process of blowing. And that current flows to and fro, as you put it, alternating its direction every 8.33 milliseconds in the USA and other countries having 60 Hz AC, and every 10 ms in countries having 50 Hz AC. Also, upon careful reading it appears to me that the statement you referred to is an example of what is known as circular reasoning. Regards, -- Al |
Regarding the aforementioned directionality-related measurements provided by HiFi Tuning, I recently posted the following in the ongoing Littelfuse thread:
Regarding the measurements described in the HFT paper (which Nonoise was
kind enough to link to earlier in this thread) which purport to support
the notion of fuse directionality:
1)Resistance measurements
related to directionality were provided for 16 different HFT fuses,
having current ratings ranging from 1.6 amps to 20 amps, as well as for a
few competitive fuses and standard glass and ceramic fuses (the
specific make of the "standard" fuses being unspecified). The
differences in resistance for the HFT fuses in the two directions ranged
from 0.000002 ohms to 0.000120 ohms. The differences in resistance for
the competitive fuses were a bit greater in some cases, with the worst
cases generally being the standard fuses, for which there was one
isolated case having a measured difference of 0.005200 ohms.
IMO those numbers are so miniscule as to be:
(a)Laughable.
(b)Very
possibly attributable to changes in the voltage of the battery in the
measurement meter, from measurement to measurement (each measurement
imposing a slight drain on the battery), and from minute to minute. Or
if the meter was AC powered, to the very slight differences in AC line
voltage that may occur from minute to minute, as various loads are
turned on and off at nearby locations.
(c)Very possibly
attributable to differences in contact pressure and contact area between
the meter’s probe tips and the contacts on the fuse. The paper presents
separate measurements of fuse resistance as measured in a fuseholder
(for just one direction), indicating that the direction-related
measurements were performed by touching the meter leads directly to the
contacts on the fuse.
(d)Perhaps even contributed to by
differences in the resistance of the measurer’s body, that would have
been paralleled with the resistance of the fuse if he or she had fingers
on the probe tips and/or the fuse contacts while the measurements were
being taken.
(e)If Geoff’s comments about all wires being
significantly directional are to be believed, then these differences
would be totally swamped by both the resistances and the alleged
direction-related resistance differences of the vastly longer associated
wiring. In the case of mains fuses, that would include the power
transformer and the power wiring in the component, as well as the power
cord and the AC wiring in and outside of the house.
I’ll say
also that the comments I provided on the HFT paper in the "Fuses That
Matter" thread (linked to in one of my posts earlier in this thread) do
nothing to provide confidence that these measurements were performed in a
methodologically scrupulous manner, that would rule out the kinds of
extraneous variables described in (b), (c), and (d) above.
Regards, -- Al |
Perhaps the following attempt at a summary of the fuse directionality debate would be constructive at his point. Or perhaps it won’t be, but I’ll attempt it anyway. The summary reflects comments that have been made in all three of the fuse threads that are currently ongoing:
1)Three different experienced designers of very well-regarded audio electronics have said, as one of them put it, that the reason fuses are directional is "the vivid imagination of audiophiles."
2)Another experienced designer of very well-regarded audio electronics who has not been participating has been cited as eschewing fuse upgrades altogether.
3)A number of others having extensive experience as musicians, professional sound engineers, and audiophiles have expressed similar viewpoints.
4)One experienced designer of defense electronics (me) has expressed significant skepticism (limited only by respect for perceptions that have been reported by a few members he considers to be particularly credible), and has emphasized that it is very easy in audio to attribute a perceived difference to the wrong variable (with the variable that is actually responsible often being very non-obvious), and has explained why measured data that has been presented in support of directionality is misleading and meaningless.
5)Numerous users of SR and other audiophile-oriented fuses have attested to their directionality.
6)A claim has been made that **all** wire is significantly directional. The aforementioned experienced designer of defense electronics has indicated that if that is so, since cable resistance, inductance, capacitance, skin effect, proximity effect, dielectric absorption, propagation delay, and the degree of pretty much all other cable effects are proportional to length, then the alleged directional effects of the AC wiring in components, and in the windings of the power transformers in those components, and in their AC power cords, and in the AC wiring inside and outside of the house (which are all in a random mix of directions), would totally swamp any alleged directional characteristics of AC mains fuses. So assertions of directionality in AC wiring and AC fuses cannot both be true.
7)As the aforementioned experienced designer of defense electronics stated in the ongoing Littelfuse thread, each individual reading these threads can and will decide about the issue for him or her self.
Regards,
-- Al
|
George, it’s not clear who your last post was addressed to, but if it was addressed to the person who posted just above that post I think you may not have interpreted what he said as it was intended.
Geoff, thanks for the comprehensive response, although I’m not sure what the strawman argument was that I was attacking. BTW, when I referred to cable effects essentially all being proportional to length I should make it clear that I was referring to power wiring. While the same is also true for analog cables, it is not necessarily true for cables conducting digital signals. And in the case of digital cables, btw, I wouldn’t rule out the possibility that they might be at least slightly directional under some circumstances, due to reflection effects that may affect waveform quality, that may in turn affect jitter. That might occur if the cable’s "characteristic impedance" is not precisely the same at both ends, perhaps due to minor soldering differences in the two connectors. Directionality due to that kind of effect, however, would be system-dependent, unpredictable, and unrelated to the direction of any arrow that may be marked on the cable.
Regards,
-- Al
|
"BTW, when I referred to cable effects essentially all being
proportional to length I should make it clear that I was referring to
power wiring."
Nice try but there is no such law as you seem to
be implying.... That’s a Strawman
argument by the way, I.e., a statement of "fact" intended to win the
argument.
Perhaps you can commiserate with the defense electronics dude.
Well, the only kind of effect this defense electronics dude can think of that would not be directly proportional to length, in the case of power wiring or cables conducting analog signals, would be antenna effects, that may affect pickup or radiation of RFI/EMI. And even in that case, it would seem expectable that the antenna effects of a mains fuse (if any) would be swamped by the antenna effects of the much longer associated AC wiring. Also, FWIW, this defense electronics dude cannot envision a means by which the antenna effects of a fuse (if any) might be different depending on the direction in which it is inserted. Regards, -- Al
|
Okay, I switched the fuse direction today and am listening. Details at 11... Before reaching any conclusions, my suggestion is that you switch it back and forth a couple of times, and listen to the same recordings at precisely the same volume settings following each reversal. In other words, try to verify that the results are repeatable, and that any differences that may be perceived are not due to extraneous variables such as differences in warmup state, variations in AC line voltage and/or noise conditions that may occur at different times of the day or night, differences in contact integrity, etc. Regards, -- Al |
To member Whitestix, thank you for the advice you provided on the previous page of this thread. Sage counsel, IMO.
Regards,
-- Al
|
Well analyzed and well said, Ralph (Atmasphere), as I would expect. BTW, Geoff has said at least one thing in this thread that I agree with, although he did not originate the saying. From one of his posts above:
Keep an open mind but not so open your brain falls out.
Best regards, -- Al |
Oregonpapa, let's suppose that in an automobile-related forum someone were to claim that changing the wiper blades on his vehicle from Brand X to Brand Y improved his gas mileage by 10%. It would seem safe to assume that pretty nearly all of us would conclude that the person making the claim is either mistaken, or deluded, or has a financial interest in Brand Y, or that something other than using Brand Y was responsible for the improvement. And unless there were indications to the contrary I for one would tend to presume the most likely of those alternatives to be the last one, that something else was responsible for the improvement. For example, perhaps it had been raining frequently, and the better visibility provided by the new Brand Y blades, compared to the aged Brand X blades, resulted in the person driving a bit faster, at a more fuel efficient speed. To those of us having an extensive background in electronic design, or to at least most of us having such a background, and who have a better than average understanding of how this stuff works, assertions that fuses can have directional characteristics that are audibly significant (especially in AC applications), engender similar reactions. In my own case, though, as I stated in one of my posts in this thread dated 4-13-2016, the degree of my skepticism is "limited only by respect for perceptions that have been reported by a few members I consider to be particularly credible." Now, why should it matter that none of the assembled experts can come up with an explanation for fuse directionality that we consider to be even remotely plausible, beyond the several possibilities that have been cited involving extraneous variables. (And btw I would have no problem if anyone who so chooses were to put the word "experts" in quotes). Well, as I said in the SR fuse thread, in a post dated 3-28-2016:
...one reason I attach significance to the lack of a confidence-inspiring
explanation is that it lessens the predictability of whether a
particular tweak will benefit a particular component in a particular
system. And one reason I attach significance to a reduction in
predictability, despite the existence of return privileges, is that ... assessment of a tweak involves an
investment of time even if it doesn't involve an investment of money.
Regards, -- Al |
Oregonpapa 4-26-2016
Al ... I bought new wiper blades from the dealer for my Lexus LS ... and
they suck. However, when I recently changed the worn Goodyear Eagles
put on by the previous owner for a new set of Michelin Premiers it was
like going from a noisy clumpy ride to gliding on velvet. I don't have a
clue about tire technology ... but I know what I hear and feel in my
car. And by the way, with the new quiet ride, the Mark Levinson sound
system has much better highs and mids. Too bad it doesn't have a fuse
that can be changed out for an SR Black fuse ... or does it? Hmmm ...
Perhaps the Goodyears would have done better if some or all of them had been re-mounted such that what was the inside surface was on the outside. That way they would be rotating in the opposite direction. Only kidding :-) Actually, I'm not surprised. One of the versions of the Goodyear Eagle is original equipment on my Porsche Cayman S. Definitely designed for performance, not comfort, at least in that version. Regards, -- Al |
Analogluvr, I read it and my reaction was similar to yours. It almost seemed like a satire of audiophile tweaks.
Regards,
-- Al
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