Why does the amplifier left speaker go right and the right go left?

Man, just switch the input cables. Job done.

Does your Pre-Amp allow you to swap L/R? Mine does, would just wire them up crossed, and switch on the Pre.  Or just leave it alone, knowing it has a quirk. 

Another useless thing would be to just tun the amp upside down, then they would be the correct side. 

What???? The ignition switch is on the floor???

Assuming you plugged the left into the left +- and right into the right side, then who cares where they are on the rear panel?  

when lefts decided to cross their paths with rights

Certainly the safety regulations in this case are strongly influenced by the highway code, as right-hand driving applies in the UK.

Laim

Bdp24 for the win!

Just an observation, my  Shindo Masetto is set up right Channel to left speaker, left channel to right speaker. I found it strange upon setup but for me what I care is about the magical sound that comes out. The late Ken Shindo was a genius in the art of building components. I love Shindo gear and the way they sound so I accept their built philosophy and just enjoy the extra sparkle in the sound they reproduce.

Let me see - solder wires to the opposite side for better sonic performance, safety reasons, noise reduction, design reasons.  Well Ok then.   

Symmetry is all wonderful in circuit designs and so many other things...but it seems to be Naim acting lame....

Unfortunate. 

What Nait is stating is nonsense. Look at a picture of the Supernait 3’s interior. There is plenty of room around and behind the binding posts. But notice the wires from the output transistors to the binding posts: they are straight with crisp angles, equally spaced. In order to wire the output normally, the wires would have to cross, ruining the symmetry. That’s the reason. My guess is Nait spent a lot of time developing that circuit board and when it came time to put it all together they noticed how the wires wouldn’t run neatly and had to cross. So it was a choice of either redesigning the board by switching around the output transistors... or change the stenciling on the back panel.

Open the cover change the wiring to also put stickers outside. or Get it done by repairer just a soldering job.

Actually, somewhere during the 50+ years I’ve been into high-end audio,, I do recall seeing at least a couple of components that have similar panel layouts, and I’m pretty sure that, when shopping for an integrated earlier this year, I found a couple of current models.

If cited correctly in this thread, the rationales for this reversal don’t seem to hold up to scrutiny. If the configuration was a way to avoid induced noise from internal components, relocating the power signal path would have resolved the problem. Apparently, Naim, like me, didn’t consider this aspect of the panel layout important enough to warrant a circuit redesign. And frankly, if Naim uses "custom" connectors, I’d expect that to outweigh such a trivial panel-layout inconvenience by a wide margin. If one can deal with the former, why would the latter be a problem?

My attitutde is along the lines of “That’s certainly worth pointing out, but bottom line, it doesn’t matter enough to warrant an entire conversation.” If you neatly route tie-wrap your cables to a rack, there’s no criss-crossing. If an amp is unracked & physically located between the speakers, it’s trivial, as one poster suggested, to merely reverse the input channels if crossing one’s pricey, uber-insulated speaker cables is a matter of concern, and otherwise unavoidable. Or whatever. IAC, it should be SOP to follow up every system modification with test content that reveals things like swapped channels, out-of-phase channels, etc.

FWIW, I’m hardly perfect myself in this regard: I got surprised by an analogous layout issue a few months ago. A new amp, just in from Germany, had outputs for two sets of speakers, but the A outputs were in a lower row BELOW the B outputs. When I first turned the thing on, there was no output b/c I hadn’t realized that I’d enabled the A outs but connected speakers to the upper row of B jacks. Oh my – I’d just assumed… But you know what they say about assumptions.

Having said all this, I want to thank the OP for pointing this out for the sake of other Naim owners. A worthy rule of thumb is: When you buy ANY European product, it’s always a good idea to RTFM first.

Pentaconn connectors, anyone?

I don't find this to be an issue in the least.  Assuming the owner/user can read, it should be easy to set up correctly.

The issue of rear panel layout probably doesn't get the attention it should.  For myself a big bugaboo is the placement of the power cord inlet.  It really should be as far away as possible from both low level input/outputs and loudspeaker cable outputs, but that's not always the case.  The worst situation tends to be where the inlet is placed between the left and right channel I/Os.  It makes it very difficult to not cross power cables with signal carrying cables.

Why is the industry locked into the rear panel paradigm?  If a component is in the shape of a box (and that's a whole other paradigm), then there are six sides where connections could be placed.  In the language of the audiophile separating the power cables from the signal cables would result in a profound sonic improvement easily equal to a major component upgrade.

and maintain compliance with safety regulations.

There you have it folks. The UK nannies strike again. Because they know so much about product safety.

Naim always did that. Naim was always a quirky company. DIN connectors, speaker wire with high inductance. Just the way they rolled. But they produced some great-sounding gear. 

What's next?

Turning the volume knob counterclockwise to increase the volume?

Total anarchy.

I find this speaker wire connection weird.  I wonder how many people that own this amp never read the manual, or the labels written on the back of the amp, and have their speaker wires in the wrong position.   

There is a simple solution, isn't there? Just reverse both the speaker cables and the channel designation of all your inputs.

My search could not find any information about other audio amplifiers, besides Naim, that reverse their speaker wire connections. Naim is known for having a unique configuration where the right and left channels appear reversed when viewed from the front of the amplifier, although they are correct when viewed from the rear.

This setup is similar to stage equipment configurations.

They can try to rationalize it however they want, but it’s just unnecessary and stupid.  If I was obsessed with PRaT maybe I might consider putting up with their backwards/different connections, but there are too many other excellent/better amps out there without having to deal with NAIM’s silliness/eccentricities. 

The information I found below provides additional facts about this speaker connection requirement.

“The specific arrangement of connecting speakers to the Naim Supernait 3, where the left speaker cables are connected to the right side inputs and vice versa, does not inherently provide direct sonic benefits. Instead, this setup is primarily due to the design and layout of the amplifier’s rear panel, which aims to optimize space and maintain compliance with safety regulations.

Naim’s design philosophy focuses on minimizing mechanical noise and interference, which may indirectly contribute to improved sound quality. The inputs are individually decoupled and hand-wired to reduce noise, and the amplifier uses ultra-low-noise components to enhance performance. However, the specific reversal of speaker connections is more about accommodating the physical layout rather than providing a distinct audio advantage.

Overall, while the connection method itself does not offer direct benefits, the meticulous design and engineering of the Supernait 3 contribute to its overall high-quality sound performance”.