1990's Olive Green Complete System - Need Help - Connected/Sound "Wrong"

Hello all,

Thanks so much for reading my post. I’m working with a super sweet client system comprised of everything pictured from my attached handy diagram, and experiencing issues with the sound quality. I’ve recently searched for hours on this forum and others, and cannot find a similar situation to use for troubleshooting.

System is comprised of a NAC 82 Preamp, NA CDX CD Player, Two HI-CAP power units, One SNAXO 3-6N active crossover, three NA 250 stereo amplifiers, finally feeding to two NA NBL tri-amp loudspeakers. All official and correct NAIM cables types within.

This system was designed and is connected in the proper “TRI-AMP” operation, using the “O/P 2” connections on the SNAXO 3-6N to each individual amplifier.

Unfortunately in this configuration, the sound quality is simply strange and awful.

• The bass is barely there, very little impact, and sounds tinny.
• The mids are overpowering, very flat/bland, and feel like a piece of cardboard is in front of them. Almost uncomfortable to listen to.
• The highs are barely there, sound very tinny, grating, and sharp. Uncomfortable to listen to.

Now if I simplify the system to just 2-ch stereo, by removing SNAXO 3-6N active crossover, and using either HI-CAP to feed the preamp, I am able to get the most glorious and spatial quality stereo only sound out of one amplifier at a time to a pair of regular speakers!

All three amps seem to work just fine. However one of the HI-CAP’s does have a very loud buzzing effect however when used in this configuration, even at idle, but it does work.

Looking for any thoughts/help/assistance here please to resolve. I do not have any service history on this system, and some of the levels (blue POTS) were adjusted from factory in the SNAXO. I adjusted them back to factory black-marker specs, but they only increased or deceased the poor sound quality that is output to the speakers per frequency range with additional testing.

Thank you for reading.


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Could the SNAXO have been modified to 362 configuration? It was a fairly common mod that meant you could more easily mix and match amps. With this, each amp does L+R for each driver.

If you could post some pictures of the inside of the SNAXO on here showing how the sockets are wired then someone like @NeilS should be able to tell if it has been modified to 362 configuration.

Hi EBWhite,

I would disconnect all of the speaker cables from the amplifiers, play some music, then using just one of the speaker cables connected to the bass drivers of one of the NBLs, systematically go through all six outputs. Using the balance control you should be able to work out which output is doing what & label them up.


Hi Richard - Many thanks for your response.

I don’t think this SNAXO was modified, however I do have several photos to share of the internal components that I am sharing along with this post right now for @NeilS to review and assist as you have mentioned.

Hi Neil,

Thanks so much for your response. I’ve actually tried exactly this, left out of my original post to keep it to a moderate paragraph length.

When I systematically went through all six outputs, they corresponded exactly with the amplifier diagram manual screenshot in my original post. Lows feeding only lows, mids only mids, and treble only treble. I also used a separate pair of B&W speakers to test to remove the Naim speakers in case they were the issue. Exact same corresponding outputs and frequencies.

And along with these six individual outputs, each output was the same poor sound quality as mentioned in my original post.

Silly question perhaps, but it is definitely a SNAXO 3-6 for NBLs?

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Nothing is leaping out at me from your pictures. I will have a better look tomorrow and compare to data at the factory.


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Many thanks - and please do let me know if you’d like any other specific system photos.

My next step is to have both HI-CAP units inspected by a professional technician, as I suspect the SNAXO is not getting enough power.

Hi Richard,

It is the SNAXO unit that came with this entire system, which included the NA NBL speakers. The back of the SNAXO says 3-6, and then next to the “6” is a professional looking label, blue, with “N”.

Check that the link plug on the SNAXO is properly inserted.

Also, is the cabling all kosher Naim?

Is the link plug missing completely and the small amount of sound coming through is just ‘bleeding’ through the SNAXO?

There should be a plug like this

Is that fitted? It sticks out the back of the SNAXO.

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Hi Stephen, I removed the Link Plug for the photo, it is inserted normally, otherwise the SNAXO does not power on.

Hi Richard, I removed the Link Plug for the photo, it is inserted normally, otherwise the SNAXO does not power on.

All cabling appears to be original Naim, has the green tag with a number from Naim on each cable as well.

Yes, of course, I just wanted to be sure the link plug was properly fitted all the way in and seated.

Shame, I was hoping for this to be it- a simple (cost free) fix.

Good luck.

Same here! At one point during my testing I was hoping this was the cause as well.