Yep - stick with nDAC set on chassis, Jim.
Correct.
Itās the sources to the NAC/Integrated that are key. One and only one source for optimum SQ must be chassis earth grounded. Historically these were CDPs with Naim, but now most people might not have a Naim CDP so you need to elect the one source device which will be chassis earth grounded - often the DAC or Streamer now. For that elected source device you switch ground switch to Chassis and NOT Float.
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Simon is correct in explaining the fundamentals. Naim has always taken great care with grounding schemes. The reason you want to have the only one component chassis grounded is that it then becomes the reference ground for all the components connected together. When you float the ground on one component then it derives its ground from the component that is chassis grounded. Having a common ground connection to the mains is advantageous because it minimizes the difference between the ground potentials of the circuits in each component. It is really just an extension of the benefit of star grounding applied to separate components.
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Ever the curious Iāve been doing some measurements on what I had access to and the results were not all that I expected so here they are for further discussion:
Uniti Atom - ground switch set to default does indeed confirm 0.1 ohm resistance between the outer of the phono sockets and mains earth.
Switch to āfloatingā and itās actually then ~800k ohm between the sockets and mains earth. Not totally isolated but close enough!
Nait 50 - no switches here but the ground post on the back of the amp is 58k ohm resistance to mains earth. Same reading between mains earth and pin 2 of an input DIN.
With the ground post then connected to mains earth as expected there is zero resistance but the surprise was pin 2 of the DIN is now 27 ohms to mains earth, same for the outer of the phono sockets.
Original Nait - a common 0.3 ohm between mains earth and the ground post, DIN pin 2 and outer of the phono sockets.
As mentioned above, Naim pay a lot of detail to grounding schemes and my results would indicate that it isnāt as straightforward as it seems with no āone size fits allā solution
The early Naits up until the Nait 3, connected mains earth and signal ground. The integrated amps since then have relied on a single external source, as mentioned by Simon, to provide this connection.
The Nait50 obviously has no switches as it is an amp (combined NAC/NAP and also no integrated source) - it floats from ground earth like all Naim NACs - that is why you need to have one and only ground earthed source to act as a star earth - as referenced by the instructions.
I think it is all straightforward with relatively recent products - and there is a one size fits all rule that you have with most Naim products. If in doubt consult your source and amp manuals, you donāt need to guess. Very old / early Naim products appear to have conformed to a different approach to the one adopted in the last 30 years or soā¦ perhaps that was an era when there were very limited or no other Naim sources.
I might be being dense but does a turntable in the mix change anything re chassis/float for the streamer (NDS)? It looks like there is an earth from turntable to phono stage and then, presumably to mains earth. Should the NDS switch float in this case?
Also, in my system the AV setup is powered on a ring main but the NDS/NAC/NAP/Turntable is on a dedicated spur. They are joined together by a (front L/R) co-ax cable from the AV processor to the NAC. Any possible issues here?
I ask because Iāve always had a low level (though occasionally varying) of hum in the room though not noticable when music playing. And, when I home demoād a possible phono stage upgrade (Tom Evans) it introduce a huge level of hum but no other candidate did.
cheers
alf
It depends on the turntable, but often the ground is simply a shield around the cables in the tone arm.
However one way to easily find ourā¦ measure the resistance between the TT ground and the TT mains earth pinā¦ if it is close to zero ohms, then the the turntable is earth grounded, otherwise you will need to ensure another source provides Earth ground for optimum performance.
With a phono preamp, you will need to see if itās powersupply earth pin is close to zero ohms against the ground on the phono connectors going to the amp.
Iāve never really understood this stuff. It looks like my 222 is set to floating. I donāt recall changing it so I think it came this way from the factory. Iām using the 222 with 555DR and two burndies so not sure where it should be set. I donāt hear any audible noise or hum so it doesnāt seem to be making a difference in the current position.
Hi James,
I discovered that, with my Ear amps, the RCA use common ground but the XLR ground floating. Does it mean that XLR can carry some RFI more than RCA if some precautions are not applied.
As you remember, I encounter, since the NC 250 and now Ear 534, some kind of RFI noises in my speakers, depending on the moments of the day.
I ordered some ferrite cores that I will apply on my speakers cables.
If it doesnāt work, will try an RCA to RCA cable.
When I had a dedicated 20A line installed for the audio system, this was done in two stages.
The first was to replace the relatively shallow ground spike with a ādelta earthāā¦three 10ft deep ground spikes laid out in a triangle (delta), which each rod at least 8 feet apart, all tied together by some seriously thick copper cables.
The dedicated 20A line came a few days later, as the delta earth took a while to do.
So for a few days I got to listen to the audio with only the improved grounding. And if I had been told that I had the full-monty dedicated line, I would have been happy with that alone.
Overall the system was cleaner, quieter, more dynamic and seemingly more extended at the top end.
When the 10ga dedicated 20A line followed it offered similar improvements to just the delta earth, but was considerably more expensive as some drywall had to be broken (and then patched) and wooden joists drilled through to allow the conduit cables to pass.
I understand that the āring-mainsā in the UK does not easily safely allow dedicated ground spikes (or three); but in most of the rest of the world, you can always improve your audio performance by putting in a better ground spike(s).
This to me is more fundamental than using some audio grade ground wire to connect the chassis of your equipment to the mains earth.
And regularly watering the ground around the spike to ensure good electrical connectivity as I once read in HiFi Review.
Water is not the best conductor to electrically couple the ground-spike to earth. There are some commercially available electrolytic slurries that have several magnitudes higher conductivity than water, that can be annointed on your ground spike(s)
It is nothing to do with ring mains or radials etcā¦ It is precisely about your earthing method provided by your utility provider.
If they provide TN-CS - like most default provisions in the UK then it is potentially dangerous to connect a local earth electrode. Should a fault occur in the distribution wiring or substation - then your earth electrode wiring could vaporise, combust or even explode, damaging connected equipment. In a non fault situation and you segment your earthing if you touch a ground earthed device and another part of your body touches TN-CS earthed device then you could face an electric shock or burns.
If you wish to use local ground electrodes - and yes it does reduce noise - I do it for non hifi reasons - then you need to convert your supply to a TT earth system. A competent electrician can do this subject to you local environment. You are then totally safe in almost all eventualities and you have low noise earthing.
So to be clear unless you have a TT earthing system - you should never use a local earth electrode for safety reasons. Of course most who have qualifications in this area will know this already.
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Tried today the Ferrite cores on my speakers cables, to see if the noise from the speaker could completely disappear. Unfortunately, not.
Next I will try RCA to RCA. Instead of XLR to XLR.
RCA gave nothing different
My dealer will borrow me an Audioquest power conditioner on Sunday.
Will try to connect the power amp and preamp to it.
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