Signal ground connection (SN3 humming)

Hi All, what’s the official stance from Naim regarding the signal ground connection?

I have a Hugo2 connection via RCA to my SN3. Only recently connected the power supply to it and noticed an hum. I previously ran via its internal battery, flawlessly.

As searching the forum suggests I’ve tested with a cable and the hum goes away by connecting the signal ground connection to the outer ring of a DIN socket but the manual states this connection is for use with turntable only…

4.10 General Connections Notes
The SUPERNAIT 3 negative input and output connections for
each channel are common. The mains earth (ground) should
always be connected regardless of what other equipment is
used in conjunction with the amplifier. The mains earth only
grounds the case and the electrostatic screen within the
transformer, and is not connected to the signal negative. In
order to avoid hum loops, the signal negative of the whole
system should be connected to the mains earth (ground) in
one place.
A signal ground connection is fitted to the SUPERNAIT
3 rear panel. This is intended to be used to connect a
turntable pick-up arm signal earth only.

The wire link from din casing to earth post is a known fix for him induced from other components and chord being quite common. I had to do it with a qutest until I put a linear supply on it that was earthed properly.

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Been reading some other posts suggesting it’s not always a good idea and can introduce unwanted noise. Hmmm, think I’ll continue to unplug it for playback

I like to unplug for playback… (from my sources; being a range of DAPs)

I find it amusing when plugging a ‘rotated out’ part onto power, that the digital sound from another nearby unit ‘drops’ playback for a moment… (but not on topic, so …)

iFi have some Powerfilter plugs that have an earth ‘pin’ that can be exploited for improving EARTHing in a system. (it is ‘by design’ intentionally accessible)
I have seen some great chewyoube videos of people building little ‘earth gardens’ to connect to, using this feature.

With a few threads’ here talking about hum (and I got it too when plugging in my Nait recently), the dealer confirmed that improving Earth (/having it checked) is worthwhile.

Whilst I gave my lil iFi Powerthingy to a mate in an apartment (and believe I am not breaking forum rules by giving mention to it so ‘half heartedly’, and I certainly do not resell them etc); that ability to build a makeshift Earth point (of improved quality) whilst using a device that can drink the bad stuff from the power line; makes them potentially practical.

I had figured to borrow one back from my friend (the apartment dweller), and to see if the amp hum can be reduced.
I understand this is different to the OPs question… and having had a Chord Hugo, I’d be using the same companies’ power bricks for such a part (if leaving it connected); but like the OP, my preference was to charge when NOT IN USE… (a heat thing for me; knowing extra heat when in use just isn’t practical for longevity of the battery cells etc)

At least it isn’t a Sony PHA3 that has a five hour runtime from a full charge (that takes more than half a day to refill); one needs to get clever with their usage patterns when using one of those :wink:

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The Hugo 2 switches into its own “desktop mode” after being plugged in for 24 hrs whereby it drops the battery level to about 80% and runs off of the PS. I’ve always been dubious of running it via its SMPS because of the bad press they receive, I’ve always been content running off battery, I use the 2go too so my only connection to the mains is for the SN3 normally.

I’d be interested to hear of any other Hugo2Go owners and whether they suffer the hum if they run off mains. Ruthlessly tagging @Naim_The_Dragon here :grin:

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No hum here — my Hugo 2 cum 2go works nicely with my 282/250. Sometimes I wonder about moving up to a TT2 and then deploy the Hugo 2 with my SN2. But currently I am quite content with what the “little“ Hugo is doing in the main system…

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I wonder if the 282/250 becomes earthed because of the separate power amp?

All Naim systems connect the signal ground back to mains earth via the source. Naim CD players and streamers are designed to do this through their DIN connections. That’s why some non-Naim sources cause grounding issues with Naim amps. This applies equally to the Supernait and 282/250.


Indeed streamers can be the ground earth reference, but only when the ground switch is set to chassis and not float on the back of the streamer.

To check whether your non Naim source can be used as ground reference for a Naim preamp/integrated, with the source completely unplugged and disconnected, use an ohm meter to measure the resistance between signal ground and the mains plug earth pin… it should be less than 0.1 ohm… and you should be fine.


Of the SN3? The Hugo won’t have an earth will it?

The Hugo’s use double insulated (IEC Class II) power supplies, so no they won’t earth the ground.

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I am curious about this as well. I have always tried to minimise the feedback as I always use PCs as my sources. The better the DynR of the DAC the more susceptible they are to pass through power noise through balanced, or otherwise, RCAs when dual earthed or there is some DC in your loop. Putting noises filters on degrades the sound always takes away the beautiful sound stage we tend pay so much for so those are non starters. I generally change cables, or alcohol clean ends, add ify protectors on the power sources. But the analogue connectors are what I spend most money on cable wise to try and minimise.

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Thanks Simon, so my only option is to link the signal ground to outer ring on one of the din sockets, or to an earth terminal on a spare mains plug/socket? Both of which could introduce noise to the amp?

I think I’m answering my own question but for the sake of a little inconvenience I’ll continue to run the 2go/hugo off of its own battery. It sounds exceptional for what it is and I don’t want to sacrifice any SQ

yes that would work - or if the amp is earthed - and the chassis is ground earthed on the amp - you could connect the earth lead between that and the audio signal ground.

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But why doesn’t my Hugo 2 cause any humming? I have no other source connected to my 282/250.


There around 30 different reasons for noise or feedback in an audio loop as it were. If one setup does not have it be very happy. So normally the top five causes are. 1. bad grounding design, double grounding, poor grounding, etc … 2. A noisy source. Like some TB4 connections that are active / dynamic are terrible. Why I use JCATs just to remove sloppy USB implementations. 3. Dirty power from some hop in your loop. Amps amplify this lot why we use HICAPs, etc … But analogues and digital audio are produced from your power stream … dirtier your power the more the amplifier will reproduce it. 4. Burn outs in connections. When someone pulls an RCA plug on a “live” system it can cause surges in the current causing burning out of cables, edge connectors, and transistors. Why we clean the connections in audio systems. The burn outs can leave carbon residue causing popping and humming on systems. Like if you are watching a Youtube video and you get a pop at the beginning of the video means the mix was switched on after the stream was recording. This normally means, but not always, you have unbalanced cables and a burnt connection somewhere. 5. Interference. This can be inside your source, or from your mobile phone, or from 5g WIFI, or 5G mobile networks, or even ground radiation. We fix this by cable tunnelling, adding shielded covers to cables, or getting really good cables that are great at preventing jitter through external effects. Hope that helps.

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Are you certain it doesn’t? It’s not hugely noticeable at normal levels. With the Hugo2 on and nothing playing turn your 282 volume up to 12 o’clock and see if there is a difference with the usb power connected and unplugged.

If not must be something different with the pre/power separates

I bought a SN3 and TT2 last month and experienced the dreaded humming instantly. This forum helped confirm the solution. I’ve left the wire in place from the ground terminal to the nearest DIN socket. Since then, the SN3 is totally silent (when it’s meant to be). I can’t detect any noise with the cable in place. Have a listen to yours to decide.

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It won’t always hum, it can vary on stray capacitance, however almost certainly SQ performance will improve with one and only source earth grounded into a Naim NAC or NAIT.

Its worth remembering any input ‘ground’ hum can be caused by

  1. a conductive ground loop where the background electromagnetic fields in your house induce a small voltage in the loop. A break or high resistance in the loop breakers this conductive loop.
  2. an induced voltage that is respect to the signal ground… such as from touching a signal lead, or a non correctly earthed turn table arm.
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or DC mix in your power loop