by ericmark »
Tue Mar 14, 2017 6:38 am
13A is the maximum that can be drawn with a 13A British plug, there is no point in using extra heavy cable, to reduce volt drop with very long runs you may need 2.5mm cable but with the power used with an audio amp that would also be pointless.
Because the supply is AC there is always some power radiated from the cable, you can show this with a neon screwdriver, so a case could be made for cable which is spaced to ensure low loss, or covered with braid, but in real terms the main thing is down to the power supply inside the audio equipment,
Today most power supplies are what are called switch mode, what these do is convert AC to DC store in a capacitor then turn it back to AC at a higher frequency, it is then transformed to a lower voltage then back to DC and smoothed, the voltage is sampled and the mark space ratio of the bit turning into high frequency AC is altered to correct the voltage, with this type of power supply it is near impossible for any mains born interference to get into the amplifier.
Any claims that the supply cable will effect the amplifier are to be considered as snake oil, and any firm advertising that supply cables will enhance the amplifiers performance should alert you to that supplier being just out to get your money.
To use contacts made from a material which will not tarnish can help stop arcing, but this is not a problem with mains supply leads, they are not prone to arcing,
The main problem with audio equipment is the speaker cable, the pair of cables can pick up interference and send it into the amplifier, if the length of the speaker cable happens to be the same wave length as the interference then it can pick up the RF and some amplifiers can't reject the signal.
So some times just making the cable a foot longer or foot shorter can stop the problem, sometimes even an inch is enough, so people have fitted new plugs and sockets and in doing so have altered the cable length, they have found a problem is resolved and so claimed it was the special plug or socket, when in fact it was due to altering cable length. So started broadcasting their findings, in good faith, but there findings were flawed.
Main thing is don't be neat, tidying up cables often means they are more likely to pick up interference, as a radio ham I have found many times the test rig has worked well, but then when made neat it does not work as well. Look at any performer using amplifiers and see how the cables snake across the floor, neatness is bad.
But main thing is try to avoid using equipment likely to produce RF interference, so all tungsten lighting with 230 Vac, no WiFi and specially no lan through the mains devices, no blue tooth, not even wireless phones or door bells, most of us simply want cordless phones and laptops with Wifi and we have to accept these items may interfere with audio equipment.
