Amateur question here. I understand the reason for star grounding, and that the audio signals are star grounded to a single point (the naim source).
However what I do not understand is why the wall power plugs that the boxes plug into needs to be star grounded as well. To my understanding, the entire audio signal has a floating ground except the source, so the wall powerpoints is only grounding the casing of the boxes.
The point of star grounding is so that each component has an equal impedance path to ground.
Many components do not in fact float the audio ground, including Naim preamps. The Uniti range has a switch allowing you to float or ground the audio to the case ground.
Edit: Naim CD players are grounded by default, not the preamps.
Actually that is not quite accurate, Naim preamps (NACs) must have a ground Earth for optimum performance and NOT be left floating. Traditionally this Earth grounding has been through the connected CDP with Naim. However as their popularity has declined other Naim sources can be elected to provide the Earth ground reference. However again for optimum performance and lowest noise to the audio signal one and only one source must be Earth grounded.
This is the purpose of the chassis/float switch on sources like streamers and products like the Uniti range⌠to ensure there is one and ONLY one earth ground connection with the chosen connected sources.
Standalone NACs do indeed have floating ground, and this earthed with the elected Earth ground reference source.
I suggest because of Naim designs (though not familiar with any changes in the new classic designs), star earthing in power strips is of no real benefit, and I think of questionable value anyway⌠possibly more of a marketing gimmick. I suspect a low impedance earth ground bus bar in the power strip would be preferable.
I am curious about the days prior to a Naim source.
My 72/HC/250 with a Linn
The NAC always was advised to be connected thru the HC which was then connected to the NAP. So the HC was the center of the star earth point. Confusing point is that my DAC earth is set to chassis and is connected to the NAC.
I am not sure if my DAC should also be set to floating ?
So for all of us having an additional phono stage which connects signal ground to power ground we should put the naim source in floating then. In theory. And if the phono amp has power ground and signal ground connected.
I believe in a power strip, a star earth connected to a shunt should in theory mean that the lowest resistance point is always to ground and so earth loops between connected devices can be avoided.
Iâm not claiming that is a fact. I am claiming that manufacturers often make that claim and in fact I often see star earthed power strips marketed as âlooplessâ.
I also donât think it is the most critical thing in the world (and I do take good grounding seriously). As such I have one power strip that happens to be âlooplessâ on a system that is not my main system and a better, but non star earthed strip on the main Naim system.
I donât believe it can really prevent all earth loops anyway because a lot of the ones that give us grief (the dreaded signal hum) are caused most often, I suspect, by linked signal grounds to different chassis.
IOW, there are more other things to go wrong with your grounding that what is in the power strip so donât lose sleep over it.
If you have a non star grounded power strip can you hear a difference from varying the plug order? Say source, pre, power against power, pre, source. I could with a CDX2/hi/282/250 but it wasnât blatant, with a 555/552/500 I find a greater effect and itâs in the area of what Iâll call musical coherence.
The closest Iâve tried to star grounding is a Musicworks ultra 2, which is ring wired except for the earths which are stared but with different length wires, I wasnât convinced by its effect on my system at the time which was the 282 based one and I preferred my linear block in source first configuration.
IIRC, the current range of Chord power strips are not star earthed because they could get better results without using star earthing topology.
Quite, and also where star earthed or bus bar earthed makes no difference on induction loop hum or not. (Ground loops)
Thanks for the reply, I think Maryland did not understand my question well.
So in summary, your opinion is that star grounded power strips are not beneficial (or insignificant)?
Have you done any comparisons?
I am asking because all the non DIY star grounded strips are more expensive than what I am willing to pay, and I rather get a strip than a hydra.
I have used various earth strip over the years and not noticed any differences. I would suggest why would star earthing in a mains extender make any difference⌠and I am not referring to possible plugging order which is a different matter and noting to do with earthing.
Star earthing in terms of small signal audio is about ensuring in a device with adopts an unbalanced signal, that the ground reference is consistent across its design⌠this is required because the signal level, as it is unbalanced is entirely relative to ground.
Naim use a single earth ground point with respect to audio in their unbalanced designs⌠so that ground point becomes the âstarâ earth point.
Mains Earth is about safety, and providing an assured low impedance path to Earth that at least matches or improves on Neutral.
Yes, but most of my stuff is non-naim these days. It kills performance on a simple tune-dem test.
Just for clarity, if I have a non-Naim CD player connected with an RCA cable, and not switched on, does that count as a grounded source? Or a powered off TV connected via Toslink? Or a turntable connected via RCA? Or is it just DIN connections?
you would need to check with a multimeter.
If the resistance between the signal return and the earth pin on the mains plug is zero or less than 1 ohm then yes that becomes your ground reference.
Obviously measure this with the CD player unplugged
Clearly Toslink cant act as an electrical ground as it is an optical, not electrical connection.
Thanks. Iâll check that out.
I suspect the so called âstarâ earth as applied to power strips came from a marketing idea that used the all important star ground thatâs applied in signal circuits, as per S-i-S âone ground and ONLY one groundâ
IMO itâs more important to have each of the socket outlets L, N & E wired in star, correctly called radial in UK and EU.
This eliminates the variable SQ perceptions of âwhich is the best plug sequenceâ that we get with the power strips using the thin metal strips formed as both plug pin contact points and linking each socket contact in a daisy chain, or bus bar.
But calling these cheap thin strips a bus bar is an insult to a real bus bar.
NB: Some of the up market power distribution units do use pukka bus bar, others are all radial wired.
Indeed Mike - though the size of the bus bar is dependent of the current it is required to support.
Bus bars can be relatively small - and when very small can be copper planes on PCBs - or they can be massive as used in major substations or power generating facilities ⌠but essentially they are typically used to carry and distribute current for switching type solutions. - of which a mains multiway adapter/power strip is an example of.
Yes if a bus bar was incorporated into a product that was not suitable for the current to be carried - I doubt it would pass certification to be sold (UKCA / CE) and yes that would not be good. But such potential shortcoming comings could equally apply to cabling used.
Surely you can just set it to continuity and see if you get a tone when the probes touch the earth pin on the plug and signal ground on an output.
Sure - whether you have a multimeter or continuity tester⌠I would suggest though you best know the threshold for âcontinuityâ for a continuity tester. A multimeter typically offers a continuity tester mode with actual resistance measurement. Many have such devices for their car etc. Anyway useful devices to have - and basic devices dont cost much.
Hi Simon, I spent my formative years working with copper bus bars carrying numbers of MW, with various voltages and both AC & DC.
Great educational experience and great fun, one minute on power dist deep in the bowels, next job up a mast in all weathers trimming DF.