Why don't amplifier Companies use high end fuses?

First, a point of information: Some of the responses which followed my previous post lead me to believe that references to "fuse rotation" are being interpreted differently by different people. To clarify, I believe that what was done by the three gentlemen I referred to in my previous post who have **actually tried** rotating fuses did NOT necessarily involve, or at least require, rotating the fuses while they were in their holders, which as has been said above would often be hard to do. As I understood it, removing the fuse from its holder and then reinserting it with differing rotational orientations would suffice, which of course would be no more difficult to do than reversing the fuse’s direction a corresponding number of times.

Also, the underlying cause of the rotational effects Ralph (Atmasphere) observed in his experiments was NOT stated to involve removal of oxidation or other impurities from the contact surfaces. I’ll quote his explanation of the phenomenon directly, as stated in this thread:

Atmasphere 5-23-2016 4:52pm EDT

It has to do with the fact that the connections on fuse holders are not perfect. The act of reversing the fuse sometimes gets you a better connection. However, directionality really isn’t the issue. Similar to a power switch, the contact area of the fuse holder that is actually doing the work is a fraction of the total contact area. As a result, if you simply rotate the fuse in its holder, you will find that there is a best position where more of the fuse holder contact area is touching the fuse contacts. When the fuse was reversed, on occasion you got better contact or worse contact, which appears initially to be a directional issue, but that is really an illusion.

Interestingly, this effect is measurable as a voltage drop across the fuse holder. As you might expect, the less voltage drop the better. So it is possible to adjust (rotate) the fuse in the holder for minimum voltage drop and thus the best performance. A side benefit is the fuse will last a little longer as the operating temperature is reduced.

Atmasphere 5-26-2016 12:31pm EDT

I joined this thread recently with some results on testing. Those results are that the directionality appears out of coincidence and that actually greater improvement can be had by rotating the fuse in the holder for best contact. The improvement is measurable and audible; descriptions others have made on this thread of what happens when you get the direction right accurately describe what happens when the contact area is maximized.

Occam’s Razor has something to say here! Given that a fuse has to be used in AC circuits and given that people report differences by reversing the fuse, and also understanding how fuses are inherently incapable of having directionality in any way whatsoever, the explanation that they somehow have an effect by reversing them in the holder is a fairly complex explanation: some sort of unknowable, unmeasurable quality of the fuse itself.

A simpler explanation is that the reversal is improving the contact area because fuse and holder are not dimensionally perfect and the fuse might sit better in the holder in one direction. By rotating the fuse in the holder without reversing it gets the same effect only more profoundly.

Does all of that sound at least somewhat implausible, even though Ralph’s claims are based on actual experiments? It would not be unreasonable to think so, IMO. However, I feel safe in saying that to most of those having an extensive background in electronic design (such as myself) the notion that a fuse would have **inherent** directional characteristics to an audibly significant degree is substantially MORE implausible.

And as I have said in a number of past threads, in audio it is often extremely easy to attribute a perceived effect to the wrong variable.

Regards,
-- Al

FWIW, with the three exceptions cited below, as far as I can recall not a single member who has reported audibly significant direction-related fuse effects has ever stated that he has done either one of the following:

1)Reversed and re-reversed the direction of the fuse multiple times, to verify that the perceived differences were repeatable.

2)Experimented with fuse rotation, to determine if rotation could achieve results comparable to the alleged directional effects.

The exceptions:

1)Ralph (Atmasphere), who has stated that he has experimentally verified that no. 2 above can be audibly significant, at least in the case of power amplifiers.

2)A member by the name of SGordon1, who reported in the Red Fuse thread on 5-3-2016 that rotational effects were audibly significant in his power amp, and consequently he "encourages everyone to experiment with fuse rotation!"

3)On that same date in the Red Fuse thread Oregonpapa stated as follows:

Warren Gehl is the chief listener at Audio Research. There isn’t a piece of equipment, repair or new, that leaves the factory until its signed off by Warren. He not only takes the time to orient the fuses’ direction, but also the proper rotational position to ensure that the equipment will sound its best when it arrives at the customer’s home.

Regards,
-- Al

It has been pointed out by Atmasphere in a number of past threads that our hearing mechanisms use certain higher order odd harmonics as loudness cues. And also that our hearing mechanisms are extremely sensitive to even trace amounts of those harmonics. Therefore I suppose it is at least slightly conceivable that very small changes in distortion that might result in some unexplainable manner from changing the direction of fuses that are used in series with the DC voltages that power the active stages of an SACD player (as appears to have been the case in the situation Nonoise described) could be subjectively perceived as a change in loudness. Although even that possibility seems unlikely (to me, at least), especially in the case of a line-level component as opposed to a power amplifier.

However I will stake my reputation, such as it may be, on the absolute impossibility of a 2 or 3 db volume difference resulting from reversing the direction of any fuse in an audio component, assuming at least that the contacts are not severely corroded and that the fuse is not on the verge of failing. And assuming equal warmup states of the equipment.

As I have said and acknowledged in many past threads, science and engineering can neither predict nor explain a lot about what we hear or don’t hear from our systems. But it can certainly predict some things. If it couldn’t, the quality reproduction of music we all enjoy would not exist.

Regards,
-- Al

Thanks, Geoff. I appreciate the recognition :-)

--Al
 

Kosst_amojan 9-9-2017
Auxinput is just lying when he says it made a 3dB difference. There’s no physical phenomenon in the universe that would explain that and that’s a difference easily measured.

Kosst, for the record note that Auxinput did not say that. It was another member who said that "I had to turn down my volume by 2-3db because after changing directions, it was too loud."

Also, IMO both Auxinput and the member who made that statement have over the years established excellent reputations for sincerity. That said, however, I agree that the stated 2-3 db effect is simply impossible, and was probably due to either some other variable or to misperception.

Regards,
-- Al

Gs5556 9-4-2017
The second reason (I’m guessing): the fuse makers cannot or will not supply technical data such as time-current curves, interrupt rating, melting, and UL approval numbers.

That’s an excellent point, IMO. I’m not sure how a design can be created in an intelligent manner, that would assure long-term reliability as well as good performance, without comprehensive technical data on the parts that are being used.

Another possibility, it seems to me, relates to expenses the manufacturer might end up having to pay under the warranty coverage he provides, to replace blown fuses. In the past two years or so there have been at least seven different members, and perhaps more, who reported in the SR Red Fuse thread that SR fuses had blown unnecessarily, often soon after being installed. In at least one or two of those cases the fuse that blew even had a higher current rating than the stock fuse. Why would a manufacturer want to risk both the expenses and the damage to the reputation of his company that might result, given also that there may be ambiguity as to whether a failure is the fault of the fuse, or the fuse being overstressed by the design of his equipment.

Regards,
-- Al