The Audiophoolery Thread.

[Craig Sawyers]

The interesting thing is that if you calculate what is going on when a 50Hz current flows, the electrons shuffle back and forth by much less than a human hair, even at 1A rms.

Somewhere lurking on this forum is a calculation of this.

Craig

[Craig Sawyers]

It was post 632 on this thread, repeated here. The upshot is that if 1A rms flows at 50Hz in a 3.3mm^2 cable, the electrons shuffle back and forth by 2um - so four time the wavelength of green light.

Craig

Suppose we take a sine wave current. The electrons move in one direction during the first half cycle. The area under the first current half cycle of a sine wave is the charge that has been moved in that time

Q = I(root 2)/(pi x f)

The root 2 gets from RMS current to peak, which is what you need for the equation.

Lets take 10A flowing at 50Hz. The charge transferred in the first half cycle is 9 x 10^-2 C from the equation. The charge on the electron is 1.6 x 10^-19 C and so the number of electrons for this charge is 9 x 10-2/1.6 x 10^-19 = 5.6 x 10^17.

That sounds like a lot, but there are 8.5 x 10^22 electrons per cc in a copper conductor!

Lets take a 1mm^2 cross section wire (that would be under rated for 10A, but this is a though experiment which will scale for different values). 1mm^2 = 0.01cm^2.

So there are 8.5 x 10^22 x 0.01 = 8.5 x 10^20 conduction electrons per cm of 1mm^2 section wire.

So in the first half cycle of the mains waveform, the electrons move 5.6 x 10^17 / 8.5 x 10^20 = 6.6 x 10^-4 cm = 66 microns.

Then in the next half cycle they move back again. So the electrons shuffle back and forth by 66um peak to peak - or about the thickness of a human hair.

Now let's scale it. Let's take a typical audio mains cable of 12AWG, which is 3.31 mm^2. And the current might typically be 1A for a really chunky class A amplifier (so 240W of standing dissipation).

That means that the peak to peak electron movement in the wire is 1/10 x 1/3.31 x 66 = 2 microns. So about four times the wavelength of green light.

For lower currents of more typical power amps, and certainly preamps the current will be <<1A, so the amplitude of electron motion is down in the wavelength of light territory.

Of course the same calculation holds for signal cables and loudspeaker cables.

SO - if for the moment one accepts that there is an audible difference between cables, the mechanism is definitely not related to the tiny AC amplitude of electron motion.

Craig

[Herald1360]

Is that number of electrons all of them, or just the ones which are available for conduction?

[Craig Sawyers]

The ones available for conduction.

[Radio Wrangler]

Applying audiophile logic:

If the amount of motion is so small, then all interconnects have to be massively stiff so that none of the motion is lost.

David

[Craig Sawyers]

The calculation is that 1cc and that weighs 8.98 grams for copper. The number of moles is mass/gram atomic weight = 8.98/63.55 = 0.141 moles. 1 mole contains an Avogadro number of atoms. So 0.141 moles in 1cc contains 0.141 x 6 x 10^23 = 8.5 x 10^22 copper atoms. Since each copper atom provides 1 conduction electron, there are therefore 8.5 x 10^22 conduction electrons per cc in copper.

Craig

[Craig Sawyers]

I've just broken open a 13A (regular!) fuse, and the wire in there is 0.4mm diameter or 0.126mm^2. Assuming that it is copper, and the full 13A flows, the electrons will shuffle back and forth by 66um x 1.3 / 0.126 = 680um or 0.68mm.

Of course, the fuse is normally there to protect against fault conditions in the power cord, and normal running current is significantly less than that for any domestic audio gear. So the electron motion is back to a few tens of microns.

Craig

[Dai Corner]

Originally Posted by Max Ripple

I stumbled upon an add for special blue coloured cartridge fuses!Other coloured version's are available too with even more outrageous claims made for them,when replacing the humble fuse in power connectors of audio equipment.
They cost (for the entry level version!)$150 each,and "discerning" audiophiles are buying them too it seems?
They don't actually claim that the fuses help create "pools of acoustic space",but they might as well do.Perhaps the space though is between the ears of the buyers's
I wondered about getting one for the 'fridge as it definitely doesn't sound right.
Nick

One wonders whether they are designed to have an artificially short life to drive future sales?

[Craig Sawyers]

Thing is that mains plug fuses have to conform to stringent British Standards, and must at least bear the ASTA diamond http://www.intertek.com/marks/asta/diamond/ .

Since this is subject to strict auditing and approvals, it is inevitable that any audiophile fuse to be fitted to a 13A plug is a re-labelled standard fuse, certainly if it has the ASTA diamond on the relabelling.

Now there is nothing against this, and companies supplying these fuses certainly incur costs relating to relabelling, and possibly in collaborating with fuse manufacturers to provide fuses with plated end caps - silver or rhodium are typical.

I'm agnostic, as you know, regarding the extent to which this makes any difference at all - hard science says that the electron motion shuffling back and forth is tiny. The main difference I believe relates to reducing the contact resistance to the mains plug, and prevent contact tarnishing (I've seen this big time in the old rubber plugs, to the extent that the plug melted).

Craig

[John_BS]

I try to avoid reading adverts aimed at high-end audio aficionados, but I was sent to this site by a friend and was unable to unhitch my gaze as I learnt more and more about fuses and realised just how ignorant I was...


https://www.synergisticresearch.com/fuses/blue/

[TonyDuell]

I think I'll stick to the offerings of companies like Cooper Bussmann.

I've used measuring instruments from companies like Tektronix, HP/Agilent/Keysight, etc. Working with signals way above the audio band. Measuring to an accuracy way above what my ears could detect (and I suspect _any_ ears could detect). And not one of them used any kind of 'exotic' fuse...

Quite simply, if the impedance of you amplifier's mains fuse makes a noticeable difference to the sound then your amplifier's power supply needs redesigning properly!

[John_BS]

But did you try reversing the fuse, as they're directional?


John

[paulsherwin]

It is well known that fuses are the biggest factor affecting an amplifier's performance. Keen audiophiles enjoy 'fuse rolling' to tighten up the soundstage and improve the bass dynamics. Some people use audiophile fuses like the ones in the link, while others prefer the warmer, welcoming sound of vintage 1960s Volexes. The most accurate soundstage is achieved by removing the fuses altogether and replacing them with 2.5mm OFC wire or the traditional steel nails.

[GrimJosef]

Originally Posted by TonyDuell

I think I'll stick to the offerings of companies like Cooper Bussmann ...

Yes. I also Like Littelfuse who do a broad range of time-delayed fuses with well characterised and documented blow characteristics. Their datasheets are full of useful information.

Cheers,

GJ

[John_BS]

As I hail originally from Sheffield I'm drawn to auditioning the steel nails. So many alloys to explore... and no more pesky blown fuses!

J

[John_BS]

Their datasheets are full of useful information.

Including directional properties? I doubt it. Second-rate.

[G6Tanuki]

Has anyone offered cryogenically-treated fuses? I'm sure 48 hours in a vat of liquid Helium would broaden the soundstage, increase mid-range presence and optimise the surrealism of the underlying metaphor when compared to the ruling zeitgeist.

Or something.

[Strange fuse-fact: one piece of RF power-equipment I designed included a 15-amp fuse in series with the RF output]

[dglcomp]

Originally Posted by TonyDuell

Quite simply, if the impedance of you amplifier's mains fuse makes a noticeable difference to the sound then your amplifier's power supply needs redesigning properly!

And according to one of the mods on the Sound On Sound forums (an ex BBC engineer and honorary dr of something audio related no less) you would be correct.
Remember the markup is in the accessories most of the time.

[emeritus]

I was intrigued by the mention (without details) of a 1,000,000 V quantum treatment.

Are there any "audiophile" MCBs