Naim power amplifiers do not have extra inductance networks in the output. Naim prefer the more elegant solution of allowing the speaker cable to provide the correct inductance and capacitance.
To do so, a minimum of 3.5 metres per channel of NACA4 or NACA5 cable is required – although the optimum length is around 5-10 metres with a maximum recommended length of 20 metres. We find the supplied Naim speaker plugs to be an optimal match for the 4mm sockets we use on our amplifiers.
In addition, the plugs are designed in such a way as to prevent them being accidentally inserted into European mains sockets - hence the warning in your Owner’s Manual
“The Naim loudspeaker connectors supplied are designed to comply with European safety legislation and must be used.”
Cable length for left and right channel should be of exactly equal length – even if one speaker is closer (as is often the case) to the power amplifier.
It is advised that you position the system away from between the speakers, either off to one side of the room or at the opposite end. As such, longer lengths of cable are ideal and will work without significant information loss.
Spare speaker cable should not be coiled – excess cable may be tidied up in a way similar to that employed in the “Jumping Jack” firework. Use cable ties or similar at either end to hold in place. Additional: I would not recommend any particular length for the folds - you can make the folds suitable for hiding but use some sense. You are most likely to end up with one cable needing to be tidied - that to the nearest speaker - giving the distance between the speakers as the amount to be dealt with. Avoid having the doubled (tripled or whatever) too close to either the speaker or the amplifier end of the cable - to give as much flexibility as NACA5 allows for the final run at each end.
Avoid running the cables parallel to mains cables.
Apart from Naim’s own upgrade cable - Super Lumina (3m/channel minimum) - alternative speaker cables cannot be recommended by Naim, however, should you still wish to try them then you should ensure that the cable is low capacitance and of moderate inductance. High capacitance &/or very low inductance cables are to be avoided at all costs and may result in damage to your amplifier.
NACA5 specifications are as follows:
Capacitance: 16pF per metre
Resistance: 9 milliohms per metre
Inductance: 1uH per metre
Minimum length: 3.5 metres per channel
Maximum length: 20 metres per channel (note that longer lengths can be used up to around 25 m but then some small signal loss must be expected)