Naim 5i: How important are Naim NACA Cables?

Alternative speaker cables are not 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 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)

The MusicWave speaker cable by itself has specifications that are fairly typical for a twisted-pair, 12 gauge copper speaker cable.  It is not a high capacitance cable design which Naim warns against using, but it is not as low in capacitance or as high in inductance as the parallel, spaced-conductor design of the Naim speaker cable:
 
Musicwave raw cable
Series Loop Resistance approximately 9 milliohms per meter
Series Loop Inductance approximately 0.5 uH per meter
Parallel Capacitance approximately 120pf per meter 
 
 
One of the functions of the network in MusicWave speaker cable is to limit the upper bandwidth of the cable to about one million cycles.  We do this primary to prevent the cable from acting as an antenna for radio frequency noise but this also brings the electrical performance of MusicWave closer to the high inductance Naim speaker cable design.  What we are doing with the network in the MusicWave cable accomplishes essentially the same thing as the Naim speaker cable which uses a long length (3.5m -20m) of high inductance cable to achieve an ultra high frequency roll off.  One of the advantages of using a Transparent speaker cable with a Naim amplifiers is that we can achieve a similar high frequency roll-off even with a short run of speaker cable.