Grounding

Sorry you might be mixing terms. Safety Earth is for safety, and shunts 'excess or stray' electricity to earth. But confusingly you can combine safety earth and ground functions together... read on.

Ground is a reference. When circuits work, . they can typically only do so against a reference. A voltage is meaningless unless it's against a reference or ground or negative battery terminal.. IE when there is a potential difference between a charge on a wire and ground reference you can measure this difference as voltage.

Now when circuits work together, it's usually important to have a good common ground or reference, such that the signal (like an audio signal) in one circuit is the same in an other. If the grounds were slightly different then the signal would be different and would be distorted. By having a common ground there is a common term of reference and the signal integrity is maintained better. Circuits can use the Safety Earth for ground, but in that scenarios Earth is used for the common circuit reference as well as safety to shunt that 'excess or stray ' electricity... Two functions with one wire 

Now you also hear the term ground or earth loops. (This can get a little complicated to understand)  This is where there is a conductive loop in the circuits caused by multiple connected  grounds, as opposed to the grounds going to a single reference point within a group of connected circuits. When this happens the background magnetic field in your house - caused usually by your mains wiring - induces a low voltage into the loop.. you often hear this as a loud hum through the speakers.. To stop the hum you need to break the loop, such as disconnecting the grounds on the signal interconnects.

hopefully that helps a bit.

Thanks Simon, That is an excellent explanation. I did just read about how voltage works so the picture is clearer. I am poorly educated in electronics and power, no surprise there, but I am finding it immensely interesting! It may take time, but considering I joined Naim  awhile ago I have improved from my first posts about where does the red and black cable plug into I am going to get some basic books on this stuff and learn, my brain may hurt but it'll be worth it. Thanks again mate.

I'm not the OP, but that's very helpful thanks Simon - I have been completely bamboozled by signal/mains grounding up to now.

Could you also clarify what floating / chassis means in this regard ?

The "floating/chassis" term, in the context of a Naim source such as a streamer, relates to the signal ground.  It should be tied to the mains ground in one place only in the system. It's all about minimising noise (and hence maximising signal) through best system earthing.  As such, you can choose to float this should there already be another source that does this in the system.

Don't confuse this with electrical safety earth - all naim items must always be mains earthed.

Hi Will99, further to Richard's comments - the 'float' setting simply disconnects the electronic signal ground from the safety earth internal chassis. The 'chassis' setting combines them. As Richard says all the Naim equipment is electrically Safety Earthed... that means (except for some devices like the Mu-so that use a system of double insulation - but lets not confuse things) the Safety electrical earth is always connected to the chassis - i.e. the metal case. So when the ground setting is set to 'chassis' the signal ground is connected to this chassis - which in turn is connected to electrical Safety Earth. If the ground setting is set to 'float' the signal/circuit ground is separated internally from the electrical safety earth and chassis..

Why is this important?

Well remember those earth loops - for optimum performance on Naim pre amplifiers  there should be one and only link from signal ground to electrical safety earth. That is only one of your sources connected to the preamplifier should do this.  Typically the Naim CD player has made this connection - however if you have no CD player you should elect another Naim source to do this function - hence the ground switch. BTW not all ground loops result in an audible hum - it depends how they are implemented - but they normally rob the audio system of a degrees of performance if they are occuring.

And finally - again as Richard said - never disconnect the mains electrical safety earth to prevent earth loops - even the suggestion sounds foolish 

Hi AussieSteve - you are welcome....

Thanks both Simon and Richard, that is very informative.Sorry to the OP for hijacking the thread, but if I may also enquire -

I would presume that the advice still applies should you not have a Naim source at all (eg. MM & non-Naim DAC only), i.e. signal ground should be tied to earth in the DAC ?

Also what if you have no Naim pre-amp, eg. Hugo to NAP ?

Yes applies to all Naim and non Naim sources into a NAC. However in a non Naim preamp it really depends on how it is designed and what it needs with respect grounding.

with a non Naim preamp into a Naim poweramp, I'd suggest care is taken to ground the preamp, as discussed elsewhere not many would recommend this... If using a Hugo I would certainly ground-earth the Hugo.. There is a FAQ on Chord Electronic's web site about how to chassis ground the Hugo...

Thanks again, this thread has clarified grounding significantly for me.