@Bob793
Just curious, 3.2m of which cable exactly?
To be clear, this isn't about which cable sounds better, more a case of which cable allows the amplifier to perform within its intended operating parameters. In worst case scenarios - too high capacitance combined with too low inductance - the stability of the amplifier is threatened. If nothing else, running nearer to the oscillation threshold is likely to give less than stellar performance and possibly cause premature failure.
Naim NACA4 (and Linn K20):
- Capacitance - 16pF/m
- Inductance - 0.93µH/m
Naim NACA5:
- Capacitance - 16pF/m
- Inductance - 1µH/m
Electrically, there really isn't anything between the two (three) above, however, at a recommended minimum of 3.5m, classic Naim requires a minimum of 56pF capacitance and 3.25µH inductance per lead. As alternative, twisted 3.5m pairs of RS 56/0.3mm (strands/strand dia.) 4.0mm2 (12ga.) single core hookup wire with 5 twists/m provides a similar electrical spec as 3.5m of NACA4 (the latter being the same 56/0.3mm 4mm2 copper with the web spacer providing increased inductance vs. the twists).
As mention upthread, there are cables from other makers that may offer close to NACA electrical specification, however, they typically do not list such, and one should know these values in order to adjust the length of these such that they approximate the 56pF/3.25-3.5µH Naim recommend as minimum.
For example, long before investing in Naim cable, I ran QED 79 Strand with the following specs:
- Capacitance - 58pF/m
- Inductance - 0.66µH/m
Discounting the capacitance, which isn't considered high, the inductance of 0.66µH/m works out to a minimum of 5m of QED 79 being needed to electrically approximate the inductance of 3.5m of NACA4.
From Naim:
"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."