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Old 1st Jul 2019, 4:43 pm   #37
Lucien Nunes
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Join Date: Apr 2008
Location: London, UK.
Posts: 1,756
Default Re: 13 amp fuse for 1.5mm mains flex?

Quote:
The reason being (I found out later) is to reduce the impedance of the cable
The idea circulates in the HiFi world that this is significant, but it isn't. A typical mains transformer in a large domestic power amplfiier has a primary resistance of a few ohms, possibly 10-20 ohms in a smaller one. Yet the resistance of a 5A fuse is a tiny 12 milliohms cold and a 13A fuse perhaps three milliohms. Saving nine milliohms in a circuit with a total resistance of many ohms is trivial.

If one insists on disregarding the load resistance and considering only the supply impedance, in a domestic situation that is likely to be in the order of half an ohm, so the fuse still only accounts for a few percent. Moving the equipment plug from one socket to another just one metre further from the fuse box would have a greater effect on the sound. Clearly, no commercial equipment could be made that intolerant of external conditions.

Or could it... further discussion invited in the audiophool thread!
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