Naim make the inductance of A5 known per meter so that customers are free to choose any other cable they wish and calculate how long that non Naim cable needs to be to provide the same inductance as 3.5m of A5.
They’re not trying to sell more cable and if you email their support, they’ll happily tell you if your desired length of non Naim cable is ideal or not, provided you know the specs of the cable.
It is in fact an elegant solution to a problem. Since everyone must buy speaker cables and all cables have inductance, then use that to remove the zobel network on the output stage of the power amp. Thus simplifying the design and reducing components in the signal path.
I’m not a power amp designer unlike some posters here. My naive understanding was the output inductor was there to provide stability when the speaker offered a capacitative load, but my background is physics and telecoms, not electronics. Can you explain how the speaker inductance does that, sorry for the naive question, as a I say it’s not my field, so I don’t see how it would work.
None of the amps you mention are subjest to the minimum length recommendation, as you should know if you have read the respective manuals. It’s the separate power amps that require this. Naim have always been quite clear about the technical reason for this. Besides, if they wanted more of your money, they wouldn’t have a shorter minimum length recommendation for Super Lumina cables than they do for NACA5.
Hi Eoink, the attached link is about amp design, the page it opens on is of interest to you if your scroll down to the section on Amplifier in-stability & subsection on Parasitic oscillation & Zobel network
It shows a zobel together with a series inductor included - with Naim that series inductor will be replaced by NACA5. http://education.lenardaudio.com/en/12_amps_3.html
@anon5525519,…I was thinking about the same thing, but thought when I read it,.that I probably did not understand really .
“He can’t have a speaker-switch that they had on ‘regular’ hifi-shops in the 70’s” .
I will await Dan’s answer, but I don’t see this as a slam dunk. In fact I got a quote from Tim de Paravicini to build me such a box, and he didn’t see any issues. But, I fully accept that theory and experience can be very different.
In my case I would rather leave a 250 on so I can experience full surround sound all the time without thinking about it. I obviously wouldn’t want to leave my valve amps on 24/7, and I would rather keep the mystique in place with the family as I don’t fully trust them, and so they leave the bottled boxes alone!
For the NAIT 5si Naim would likely still recommend at least 3.5m of NACA5 per channel, but it’s not as essential with the integrated amps as it is with the classic power amps where 3.5m of NACA5 is the recommended minimum due to the cable being seen as part of the amp output stage.
The power amps in the integrateds (and all-in-ones) are all based on the work begun developing the original NAIT 5i, which was purposely made more tolerant of the speaker cable type and length used.
The current power amps are also a bit more tolerant than the earlier power amps, but experience and tests that I’ve conducted with others definitely show that the amps perform better and sound more “comfortable” with longer lengths of NACA5, to the point where I distinctly preferred 5m to 3.5m and currently use 10m in my own system at home.
I think Naim is one of, if not the most, honest to goodness hi-fi companies on the market. In my opinion, they would be the last company on earth to try and cheat punters by maximising returns with a few extra metres of cable.
If you feel you cannot trust Naim, then maybe you should move on to something else.
I guess I bought the longer lengths hoping for increased SQ but many peace of mind. I don’t notice much difference in sound quality but I wasn’t sure about having 1m lengths fed into a switch so I went for peace of mind and got the longer cable.