Nait 5si - hum issue

I know this problem has raised before, but on long closed topics.

Today I received my new and boxed Nait 5si to replace my 27 year old Nait 3. It’s intended use is in our living room where it linked up to a budget NAD CD player, a basic DVD/Blu-ray player and a decent Audiolab DAC which offers Bluetooth, an optical cable from the TV and coaxial cable from the CD player. I reused my Chord cables so I’m using both DIN connections and only one RCA.

From the moment I plugged it in there was audible hum linked to the volume control, hence a proportional increase in noise concomitant with volume increase. It remained even when I removed and tested all the inputs systematically.

To check it wasn’t a simple malfunction I plugged it into my office speakers (Wilson Benesch run through a 102/180 combination). There was no issue here which suggests that it is something to do with the cable spaghetti behind the tv stand.

But how do I solve this? Or do I just live with it? I doubt it will be all that noticeable at the volumes we normally use it at. As an aside, am I the only baby boomer whose teenage children ask me to turn the volume down?

And a shout out to the Nait 3 which gave me trouble free service for almost three decades with only one service to replace the caps, and new rubber feet a year ago.

It sounds like an earthing issue if its coming through the speakers. Suggest you start by disconnecting all the sources, and add them one at a time to see which one may be causing it

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You are definitely not the only one who gets their children telling them to turn it down, mine are 18 and 23!

The youngest has a decent rig in her room (Rega 1, Acoustic Energy 100 and Project amp) and I live in hope of the day I tell her to turn it down.

First question on the hum, given the same spaghetti at the back how was it on the Nait 3?

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No problem at all - just a bit of crackle from the volume if it had been turned off when we were away. That’s the mystery I suppose…
So far my two have no interest in audio equipment - just bluetooth speakers for their ubiquitous phones…

Yes, tomorrow I will have another go at this. What I didn’t mention was the other stuff plugged into the mains - electric piano, PlayStation, TV box, etc

My eldest actually prefers the apple earbuds to the numerous decent headphones I’ve bought for her…….

Ok, odd one on the hum, but has to be something in the very local circuit given the clean bill of health on the other system, guessing newer design being more susceptible to interference from a wall wart power supply.

Presume you’ve run new amp clean with only one source and everything else off and unplugged from the power sources where you have it situated?

Apologies if this is classic, “well yeah, I’ve done that”

Sorry, missed @GadgetMan giving same advice and response.

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I seem to remember that I did try it without any sources and it still hummed. Which is really odd in many respects. I think I need to go through everything again tomorrow in a more systematic way.

Might not be practical but if it was ok on the Wilson’s then swapping in the speaker cables from that setup to this one might cut down the permutations and at least narrow down the focus.

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Thanks, Adam. Good point. The best system uses Naim NAC cable and plugs whereas the tv system uses fairly basic cable and banana plugs.

The only comment I would make as a consumer, is that the addition of a headphone socket and the introduction of RCA connectors, suggests Naim was becoming a little more mainstream. But mainstream audio should not be too fussy…

I remember the buzz when I stacked my Naim 90/92 combination two decades ago and realising just how careful one had to be with Naim equipment.

I suspect your hum may be a result of the different signal ground / mains earth arrangement on the old Nait compared to the new. Sources fed from wall warts or with 2 pin mains connectors can cause hum with the later amps. As you don’t have a ground post on the 5si, try connecting a wire between the outer of one of the RCA sockets to mains earth and see if that gets rid of the hum.

See here as to what I mean

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Totally agree, hum is so frustrating, so just wanted to start to cut down on the variables to get back to a known trusted last config.

If it still hums on the other speaker cable then at least it makes it more fundamental and cuts down on the A / B experiments which make you question your sanity.

Good luck, we’ve all been there!

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Thanks, James. It sounds complex but I’ll give it ago.

I recently bought a Nait XS2 and hooked up my kit , voyd turntable, Puresound P10 , Marantz 6006 UK ed and Technics STG70 tunere with no hum issues.

Then I tried an old Yamaha DVD 2700 , this caused a massive hum issue , this is a two pin mains plug
Very odd as the Technics and Marantz are also two pin.

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Thanks for all the replies.

I re-tested the Nait 5 with my Arcs in the office and it was far, far better. Perhaps a little hum at high volume. But nothing that would be noticeable if I were to play music at that level!

Then I tried my Nait 5 with the both the original cables and NAC cables in the living room with only the Nait plugged into the wall socket, and everything else removed / disconnected. On both occasions it hummed, maybe slightly less with the NACs but certainly very audible.

Thus, the issue is something to do with the combination of the Nait and the circuitry in the room, and I can safely discount variables associated with cables or inputs - or even the gang plugs - since the hum is present without any of these things.

The final question is whether every Nait 5si would produce the same results in the room, or whether my item is faulty. A shame if so, because I got it brand new and boxed for a great price.

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I had a similar nagging problem with my 5i-2 some tie ago and i thought i had to live with it. I have a Yam cds-1000 cdp and thought this might be the culprit (double insulated). It got to be really annoying at some point and really put me off the amp. I ended up rearraging the whole nest and it completely disappeared and is a non-issue now for me. It is now super silent background all the time. I really couldn’t explain what was causing it at the time, it just seems like the naim amps can be tempremental now and again but it hasn’t happened since. I think maybe upgradeing the power strip to an Olsen hosp grade unit did the trick but i’m not really sure of this. The olsen has a double grounding (electrical not signal) casework and it has been rock solid since! The previous power strip was a brennenstuler or something similar and this may have had poor grounding?


Thanks, Henryski. I have contacted the seller / dealer and will demand a visit the their shop to determine whether it’s a problem with the electrics in my house or a faulty amp. Funnily enough, they directed me to this forum!
I think it was the post about the marks on a new boxed item that made me think I was being too accepting and passive about the situation. Like you, it has put me off the amp (though it sounded great last night just using Bluetooth at low volume), and I am considering rehabilitating my Nait 3 rather than giving it to my brother in law…
I think the key thing is that the hum increases with volume, which doesn’t sound like a simple earthing issue to a non-electrical engineer like me; and it continues without any inputs at all.

The problem i had initially seemed like an intermittent problem and so didn’t really put me off the amp at all, the humming was quiet but annoying as when you hear odd things like this they can distract you from the music even though i couldn’t hear it as volume was increased but i wanted a totally silent background and now i have it. Power cables almost touching or other cables touching can have a similar effect too. Just check all you’re cables are seated correctly esp the iec inlet, it really needs to be pushed in all the way to mate properly with the blades Stick with the amp as it’s a beauty, you will not get a better amp anywhere unless paying 2k or more and even then it won’t be a big jump - the SQ really is stunning once set up correctly and you’re getting the best out of it!.

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