Fuses fuses fuses

Who are these 'naysayers'??

The ones saying they can hear the difference, or the ones that confirm that there is a reason they can hear a difference?

I suspect those two groups are not the naysayers... because confirmation isn't naysaying.

Best I can make out, theres only one naysayer on this thread so far...

why on Earth would they have even had someone test fuses if not to prove - or at least show evidence - that fuses in general are directional and that HiFi Tuning fuses exhibited better measured characteristics in terms of conductivity than other high end fuses of that time period as well as stock fuses? HiFi Tuning believes in fuse and wire directionality.

A much simpler answer is that they want your money and the way they are getting it is by making gold-plated fuses. The marketing rhetoric is of course to separate them from the much less expensive gold plated fuses used in cars.

This is an example of Veblen Effect.
http://www.businessdictionary.com/definition/Veblen-effect.html

No.

A fuse has a voltage drop and in the case of fast blow fuses, one that can be pretty variable as current varies through the device. This usually has an adverse effect on the sound if nothing is done in the circuit to deal with the phenomena.

Eliminating it is usually not an option as the equipment can become a shock and fire hazard and may do things like blow up amps and speakers if something goes wrong.

DC or ac application of a fuse in the world of audio means it is subject to having signal modulated though it, in almost every single case of use. Except that of lets say a DC output power supply into another dc circuit. Minimized flow changes.... but there may still be some residual modulation in the throughput of the given fuse, if it is hooked up to a circuit which modulates draw..as... Audio = inconstant dynamic ac signal.

+1
Reducing intermodulation is indeed the name of the game.  If employing fuses in DC circuits, local bypass capacitance is always a sound design practice.

We don't employ any fuses in the DC circuits of our equipment. They are all on the AC primaries of the power transformers involved. In most of our amplifiers there are three power transformers per channel. They are there to help reduce intermodulations that can otherwise occur in the circuit.

@timlub  you are correct. Did you read my prior posts?

What possible financial motive would Audioquest have in promoting cable and wire directionality?

Cables can be built in such a way that they can be directional. The classic from of this is of course an interconnect with XLR terminations. It can only be plugged in one way.

But RCA cables can be built so that the shield is only tied at one end. Often this type of cable can express a directionality depending on how well the equipment in the system is grounded.

So there is a very practical reason for Audioquest to promote such a thing; hard to say if its financial but that is your speculation not mine.

Now let's entertain for a moment that raw wire and fuses are directional. Let's further say that you put them all in the same orientation in the equipment. The result would be high distortion, as the wire and fuse(s) would act like a diode, and thus rectify the audio signal. This is one way in which fuzzboxes (an electric guitar effect pedal) operate.  Fuzzboxes are called that because of the sort of distortion they make.

As you can see, in the right hands a fuzzbox can really be a nice effect:

https://www.youtube.com/watch?v=JgqVHQITciY

But it does not work for hifi even though it sounds cool on a guitar. Its exactly the opposite of hifi: Distortion!

Now let's instead put all the wire and fuses in such a way that they are not all creating one series diode. In this case, the signal will still get rectified, only in a variety of different ways. This too will cause distortion.

Its pretty clear that most audiophiles would like to (and do) avoid that phenomena. To that end, non-directional wire and fuses should be sought out!  If you have the pesky kind that is directional, count on it to add distortion to whatever signal is flowing through it.

 

Not to make too fine a point of it, but has anyone here noticed that I have confirmed by measurement that if you place the fuse in backwards that you may indeed hear a difference?

Those that say otherwise raise their hands:

Take another look at my posts on this topic. In all of them you will see that I confirm that what is being claimed as heard could be real and that it can backed up by measurement. The thing that seems to be tripping y’all up is that the measurement confirms what you hear and at the same time shows that the phenomena is **not** due to a fuse being directional but instead just simply the resistance across the fuse is different.

BTW, from the HiFi Tuning website, we find a PDF document with fun facts about these fuses:
http://www.partsconnexion.com/prod_pdf/hft_facts.pdf

Note that they list different resistances depending on direction. But also note that the resistance is stated in ’mOhms’. Its unclear what the small ’m’ is for, but if that is ’milli’Ohms then their measurements are a mile off.

On the HiFi Tuning fuses we have here, they measure about the same as the leads of the meter do shorted together, about 0.1 ohm. In milli-ohms that would be 100 milli-ohms (but we know that the probes are that much already, so the fuse is much less), so my guess is that by the ’m’ they are probably trying to say ’micro’ (which is normally expressed with a ’u’ which is as close as a keyboard can get to the Greek symbol Mu).

I’m not sure how you would measure that accurately, but one thing is certain and that is the meter and probes used for the test plus minor resistances across the contact of the device itself are likely responsible for any differences seen. Heck, if you simply took the same measurement twice with a meter with that resolution (which is a very expensive meter) you would likely find larger differences without reversing the direction!

So I think we can see that the idea of the manufacturer’s PDF as suggesting directionality is completely false. A better interpretation is that the *average* resistance of the fuse is going to be in that ballpark. I think they have done a mis-service as these numbers, when so obviously misinterpreted, spark a lot of useless debate.

Now I’ve already shown why there is directionality and that its not something within the fuse. This is confirmed by the numbers I’m seeing on the HiFi Tuning PDF- the latter are far too small to play an influence in the voltage drops I’ve measured!

So again: reversing the fuse can be audible, even though the fuse itself is not directional. So the people that hear this and find it repeatable are probably hearing it (unless they are experiencing expectation bias) and those that don’t may not be hearing it (unless they are experiencing expectation bias).

>>>>>All we need? If it’s so easy to measure why don’t you or one of the other naysayers measure it? You’re just guessing. Why is it the folks that are already on board the fuse directionality AND Wire Directionality train are supposed to be the ones to measure it?

I have measured it, and often because its so easy. Takes out the guess work. Why people might want to measure it is if they want to see how this actually works with their own eyes (and ears). Its pretty powerful when you can confirm with a simple measurement why it is that reversing the fuse can have an audible impact and its something no-one (not even naysayers like yourself) can take away.

To clarify this more, it "maybe" only audible if the supply stages after the fuse/holder are NOT regulated. Most sources, s/s preamps are so it shouldn't be audible .

+1; Regulation does seem to help. We don't hear any effect in our MP-1 preamp which is very tightly regulated with plenty of headroom.

Sorry if I put words in your mouth. I appreciate that you have clarified what I thought you meant.

No worries! Happy to help out.

Totally agree. They refuse to defuse but choose to infuse an effusive obfuscation instead. Obfusely everyone knows a fuse when flipped around is an esuf which sounds different. Now you can't argue that

+1 and really gets to the heart of the debate on fuse threads.

I don’t want to put words in Ralph’s mouth, either, but I’m pretty sure he’s not really on board the whole fuse directionality train. His argument is (and I suppose he could possibly be accused of fence sitting on fuse directionality) that when someone flips the fuse it somehow magically gets a better grip in the fuse holder. Cough, cough As I recall the other fence sitter Almarg agrees with Ralph in this regard.

Thanks, Geoff, that was what he said!

Actually that isn't what I said.

Its not magic.

Its the simple fact that neither the fuse nor the fuse holder have perfect dimensions. As a result, there is a small amount of resistance at the contacts as the fuse sits in the holder. If you shift the fuse around you can reduce or increase that resistance. That is why they **appear** to be directional.

Now this is easy to measure. All you need is a DVM (Digital VoltMeter) and you simply measure the voltage drop across the fuse in the circuit. Its not going to be very much, so a DVM with more than 3 1/2 digits is helpful but not mandatory. If the fuse is in an open holder, you simply rotate it in the holder and you can watch the voltage drop across the fuse rise and fall. The least voltage drop is what you want. 

Panel mount fuseholders are harder to deal with because you can't rotate the fuse while the device is on (and BTW, this is not for someone who does not have technical skills as you can zap yourself easily enough, so if any of this sounds weird or mysterious take the unit to a technician and have him do it) so quite often the remedy is to simply reverse the fuse in the holder. But you could spin it; the problem is with a panel mount holder its going to be random results. **That** is why it **appears** that there is a directionality!

So to be very clear this is only reducing the voltage drop of the fuse **in the holder**. Its not only audible its also easily measured.

An alternative is to use a better fuse. That is why we use FNM types with the larger fuseholders on our MA-2 amplifier. They put considerably greater pressure on the fuses, which have much larger (and usually silver-plated) contacts. Now we've been doing that since the inception of the MA-1 way back in 1990; that's how long we've been aware that fuses can be audible in the circuit.