What Amp fuse do you have in the plugs of your kit ?

[RobbieGong]

Some say 13 amp is too much ?

[Firebottle]

Tuner, CD player, DAC, TT, I use 3A.

Power amp 13A, though there is usually a smaller value fuse on the back panel :D

[Macca]

13 amp in everything (except the power amp lead, as that came with the power amp so I've no idea). I don't actually think it matters as far as the sound goes.

[CageyH]

Fuses in plugs? A quaint concept.... ;)

[Firebottle]

Ha ....isn't it just :rolleyes:

[Wakefield Turntables]

Go schucko

[Pharos]

The general rule safety wise is to use the lowest value that is usable without blowing, this offering maximum equipment protection. The resistance will be insignificantly different whatever the value, and the contact resistance similar.

Roughly, look at the maximum power consumed, calculate the current for that power, and add say 10% to that for fuse current value. I'd rather risk fuse changes than serious equipment damage.

[Ali Tait]

You can work out what is required using the formula P=I*V, where P is power or Watts, I is amps and V is Volts. You know the mains voltage is 240, and most kit will tell you on the back what the required wattage is, so if Watts= Amps times Volts, then Amps= Watts divided by Volts. This will give you the current draw of the piece of kit and hence the required ampreage of the fuse.

[struth]

nice explanation Ali of the piv triangle.

[Barry]

Tuner, CD player, DAC, TT, I use 3A.

Power amp 13A, though there is usually a smaller value fuse on the back panel :D

Agreed, it's what I use.


The general rule safety wise is to use the lowest value that is usable without blowing, this offering maximum equipment protection. The resistance will be insignificantly different whatever the value, and the contact resistance similar.

Also agree.

Apropos the additional series impedance imposed by a 3A fuse, it is easily calculated.

BS1362 cartridge fuses are 1" long, and for a 3A rated fuse contain a copper wire 0.15mm in diameter. The series resistance is thus 0.025 Ω.

At 50Hz, the skin depth in copper is 9.33mm, so since the wire has a radius of 0.075mm, the current density in the wire is uniform over the cross section of the wire. The inductance is thus μ0/8π = 5.10-8 Hm-1, or 1.27nH. At 50Hz the inductive reactance will be 0.4μΩ.

Thus the series impedance at 50Hz is 0.025 + j4.10-7Ω. This to be compared with the typical source impedance of the UK mains supply at the wall socket of 0.25 + j0.23 Ω (IEC 725:1981 assumes 0.4 + j0.25Ω, so the UK mains supply is a little better in this regard).

Of course with current surges the effective frequency will momentarily be much higher, but even at 1000Hz, the series impedance of the fuse will still be small relative to the source impedance.

Therefore the series impedance of a 3A BS1362 fuse is normally less than one tenth of the mains source impedance, and thus should have absolutely no audible consequences; though some might dispute that.

[bosa]

Am I right in understanding that the fuse is there to protect the cable against fire in the case of equipment faults, since UK rings have a larger current capability (depending on the circuit rating) than say EU star systems that may have lower ratings. If the cable is capable of high current as in most specialised cables, then it does not matter that the fuse is 13A. If however you have a dedicated lead for equipment that only generates a few watts, for example my TT PSU then the fuse should match the cable so in this case 3A.

[Pharos]

I have to congratulate you on bothering with all the AC theory calcs, I just could not bother even if I had the raw data because instinctually alone, it is apparent that the fuse is a relatively small factor.

[Macca]

Am I right in understanding that the fuse is there to protect the cable against fire in the case of equipment faults, since UK rings have a larger current capability (depending on the circuit rating) than say EU star systems that may have lower ratings. If the cable is capable of high current as in most specialised cables, then it does not matter that the fuse is 13A. If however you have a dedicated lead for equipment that only generates a few watts, for example my TT PSU then the fuse should match the cable so in this case 3A.

Yes the plug fuse is there to stop the cable from catching fire in the event of a fault. It serves no other purpose except to - allegedly- ruin sound quality.

[struth]

Agreed, it's what I use.



Also agree.

Apropos the additional series impedance imposed by a 3A fuse, it is easily calculated.

BS1362 cartridge fuses are 1" long, and for a 3A rated fuse contain a copper wire 0.15mm in diameter. The series resistance is thus 0.025 Ω.

At 50Hz, the skin depth in copper is 9.33mm, so since the wire has a radius of 0.075mm, the current density in the wire is uniform over the cross section of the wire. The inductance is thus μ0/8π = 5.10-8 Hm-1, or 1.27nH. At 50Hz the inductive reactance will be 0.4μΩ.

Thus the series impedance at 50Hz is 0.025 + j4.10-7Ω. This to be compared with the typical source impedance of the UK mains supply at the wall socket of 0.25 + j0.23 Ω (IEC 725:1981 assumes 0.4 + j0.25Ω, so the UK mains supply is a little better in this regard).

Of course with current surges the effective frequency will momentarily be much higher, but even at 1000Hz, the series impedance of the fuse will still be small relative to the source impedance.

Therefore the series impedance of a 3A BS1362 fuse is normally less than one tenth of the mains source impedance, and thus should have absolutely no audible consequences; though some might dispute that.

took the words out of my mind Barry :lol:

[Arkless Electronics]

Agreed, it's what I use.



Also agree.

Apropos the additional series impedance imposed by a 3A fuse, it is easily calculated.

BS1362 cartridge fuses are 1" long, and for a 3A rated fuse contain a copper wire 0.15mm in diameter. The series resistance is thus 0.025 Ω.

At 50Hz, the skin depth in copper is 9.33mm, so since the wire has a radius of 0.075mm, the current density in the wire is uniform over the cross section of the wire. The inductance is thus μ0/8π = 5.10-8 Hm-1, or 1.27nH. At 50Hz the inductive reactance will be 0.4μΩ.

Thus the series impedance at 50Hz is 0.025 + j4.10-7Ω. This to be compared with the typical source impedance of the UK mains supply at the wall socket of 0.25 + j0.23 Ω (IEC 725:1981 assumes 0.4 + j0.25Ω, so the UK mains supply is a little better in this regard).

Of course with current surges the effective frequency will momentarily be much higher, but even at 1000Hz, the series impedance of the fuse will still be small relative to the source impedance.

Therefore the series impedance of a 3A BS1362 fuse is normally less than one tenth of the mains source impedance, and thus should have absolutely no audible consequences; though some might dispute that.

Yep spot on.

It needs saying that initial surge current for many items is so large that it makes a mockery of any attempt to specify "correct" fuse ratings. Toroidal transformers are the big culprit here and it is quite normal to need say a 10A fuse for something which draws only half an Amp continuously if the fuse is not to blow due to the switch on current drawn;) In the case of high power amplifiers using toroidal transformers (500W +), and which don't have soft start built in, I have known the switch on surge be enough to cause nuisance tripping of 20 and 32 A circuit breakers at the consumer unit!

[Barry]

Circuit breakers are much faster acting than fuses - typically acting within a couple of cycles.

Fuses will pass their rated current indefinitely. At 10x that current, the fuse becomes weakened so will melt and break after a short time (seconds) . To 'blow', fuses need at least 100x the rated current.

http://www.specialtycontrolsystems.com/weidmuller/fuses/fuse_time_current_curves.php



As an aside, are there audible differences to be heard between circuit breakers and fuses? :D

[walpurgis]

I thought the fuse was there to stop the plug melting :scratch: ;)

[Arkless Electronics]

Circuit breakers are much faster acting than fuses - typically acting within a couple of cycles.

Fuses will pass their rated current indefinitely. At 10x that current, the fuse becomes weakened so will melt and break after a short time (seconds) . To 'blow', fuses need at least 100x the rated current.

http://www.specialtycontrolsystems.com/weidmuller/fuses/fuse_time_current_curves.php



As an aside, are there audible differences to be heard between circuit breakers and fuses? :D

Indeed yes.

As to the last sentence well obviously we need a 30 page thread to debate circuit breakers V fuses for sound quality.... What's the betting some tosser will start making "audio grade circuit breakers" next... sad thing is some would buy them!!:eek: Absolutely anything where the original can be simply unplugged/disconnected and the replacement is equally easy to fit seems game for exploitation....
I should copyright it before Russ Andrews sees this :lol:

[Ali Tait]

They already make them Jez.

[Macca]

They already make them Jez.

Give it up Jez. It's over. They won.

[Barry]

I'm just waiting for an audiophile mains meter (and a transformer to replace the one at the substation)! :D

[RobbieGong]

I'm just waiting for an audiophile mains meter (and a transformer to replace the one at the substation)! :D

:lol: and they'd sell at £5K+ cause there be plenty audiophoolz ! :D

[Macca]

Audiophile electricity substations built from brushed aluminium billets with gold highlights and blue LEDs - and costing 1000 times the actual price of materials and labour. Coming soon!

[Macca]

Then we have Audiophile electricity pylons: built from rare mandingo hardwood and ivory and costing... (cont P94)

[Arkless Electronics]

They already make them Jez.

Christ on a bike! Yes you're right!! http://www.audiophil-online.de/hifitest/sicherung/ahp-klangmodulIIIg.html

[struth]

Would ban you all but im retiring soon and hoping to get fired first;)

[Arkless Electronics]

Give it up Jez. It's over. They won.

Never!!!! We shall defend our hobby, whatever the cost may be, we shall fight in the bake-offs, we shall fight in the hi fi dealers , we shall fight in the listening room and in the shows, we shall fight in the lab; we shall never surrender :eyebrows:

[RobbieGong]

Never!!!! We shall defend our hobby, whatever the cost may be, we shall fight in the bake-offs, we shall fight in the hi fi dealers , we shall fight in the listening room and in the shows, we shall fight in the lab; we shall never surrender :eyebrows:

and we'll defend our right in our homes cause not even 'er indoors can stop us :)

[walpurgis]

Right. I'm going to have a nice cuppa and a biscuit, while the lunacy subsides (I expect). :)

[Firebottle]

and we'll defend our right in our homes cause not even 'er indoors can stop us :)

It's funny though, nice one Jez and Robert :cool:

[Pharos]

"Never!!!! We shall defend our hobby, whatever the cost may be, we shall fight in the bake-offs, we shall fight in the hi fi dealers , we shall fight in the listening room and in the shows, we shall fight in the lab; we shall never surrender "

Ultimately you'll have to surrender to truth AE.

[Ali Tait]

Christ on a bike! Yes you're right!! http://www.audiophil-online.de/hifitest/sicherung/ahp-klangmodulIIIg.html

There is no hope. :-)