Naca5 polarity

I’ve read some posts here and in other forums that NACA5 polarity can be determined by “small ridge”.

Small ridge = red plus
No ridge = black minus

Does anybody have official information from Naim that confirms this? I’m asking because I’ve found some photos of NACA5 which are terminated opposite - with “black minus” on ridge side.

Good practice is that the ‘plus’ or ‘positive’ is usually marked on the cable … if these two are mixed-up, I don’t really see an issue with sound quality however.

The only reason for the ridge is to make it easier to make the correct connection at both ends. The convention is to use the ridged side as positive, but if you use it as the negative, that’s fine, as long as you do the same at both ends.

This was taken from an old Naim speaker manual.

“Finally the amplifier output speaker cables, with their
custom Naim plugs, should be connected to the input
sockets on the back of the Passive Crossover Units.
Ensure that each positive plug - identified by a rib on the
side of the cable and a tag marked “pos” on the side of
the connector body - is inserted to the red input sockets.”


As this, I was connecting one the other day in a second system and my dealer confirmed this, ridged edge is positive and there is “POS” on the clamp plug if fitted.

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That’s not true. Naca5 has directionality – and that’s the reason it should have strictly fixed “+” and “-“ meanings. Otherwise directionality will be reversed.

So it seems ridged side is “positive+”.

Thanks to everyone.

Thanks, this is what I was looking for :slight_smile:

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