Some say 13 amp is too much ?
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Some say 13 amp is too much ?
Tuner, CD player, DAC, TT, I use 3A.
Power amp 13A, though there is usually a smaller value fuse on the back panel :D
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.
Fuses in plugs? A quaint concept.... ;)
Ha ....isn't it just :rolleyes:
Go schucko
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.
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.
nice explanation Ali of the piv triangle.
Agreed, it's what I use.
Also agree.Quote:
Originally Posted by Pharos
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.