Mains extension blocks


Darkebear has tried a few LAN cables as recently reported in the ND555 thread. As I found with his plug order scheme I don’t always agree with his conclusions where I’ve tried them out in my system but they’re always useful input.


OK – this thread has finally gotten me to sort out the rat’s nest in my router/switch/AV cabinet in the living room, in which there were not one, but two surge-protected strips daisy-chained to one another. (always a great idea…) i replaced them with one strip that has a circuit breaker rather than surge protection; unfortunately, it has a lighted power switch – but you can’t win 'em all.

sounds the same!


with regard to multiple earths - there is no real issue if with in the same ground zone / reference (as you get typically within a house - excluding outbuildings) other than one typically will be creating a simple inductive loop and inducing a voltage - usually at mains frequency - at very low level. This induced voltage could in extreme situations interfere by adding noise or errors to the encoded voltage values - so you might see an increased data error rate - probably only really noticeable on very long links between 50m and 100m near the upper end of the working speed of the link however.


Ken - if your mains is quite noisy anyway - i’d be surprised if you don’t hear a noise concentration near the PSUs such as the 552PS plugged into that mains. I suspect if you plugged your 552PS into clean mains - you wouldn’t hear too much noise from it with the radio.
This is how voltage noise can couple into other electronics - and why physical decoupling can be often preferable


my hifi is supplied from a 10mm sq radial, which, as far as I understand, provides a low supply impedance. if this isn’t clean, then it must mean the supply to the house is also not clean so I guess there wouldn’t be any opportunity to plug into ‘clean’ mains…

interesting experiment nevertheless…



Ken not really - if you have a noisy mains connected to a CU and a separate radial from that CU going to your hifi, RF noise - albeit attenuated will be present on that radial… and of course depending on routing of the radial the noise can couple between the cables - though less likely if routed very separately with good physical separation between them and no parallel runs.

But as you say in addition to your mains - and possibly more so if your earth if PME you may have rather noisy earth entering the property. I converted my mains earthing to a TT setup using an electrician. That very much reduced the mains RF noise in my property. Admittedly I did this for other reasons (very sensitive RF electronics) but my hifi absolutely benefited as a bonus.

RF noise and low impedance mains don’t really affect each other and are address different things.


Simon, Is low impedance mains a bad thing? I thought it would be very good.



Low impedance mains is a good thing - it helps larger power-supplies perform better with less performance variation. Power amplifiers, all things being equal, will almost certainly sound better fed by low impedance mains


Could be expensive if you have to keep feeding him.


:grinning: indeed - but my point is you need to have the work certified - it was easier and more assured to pay for an electrician to do it rather than attempting to do it myself and then getting the work inspected and certified… only to find there is an issue!!

But would i have done this just for my audio? - possibly not… but I am glad I did


I’m not convinced this will be that helpful in a typical Naim type audio system. With a local neighbourhood all on PME (I assume TN-C-S) the communal combined neutral (N) & earth (E) might well be noisy. But converting one property to TT will still carry the same N & the potential of local area PME connected noise.
I fully understand the importance of a quiet earth for “other reasons (very sensitive RF electronics)”, but such a quiet earth for Naim systems where its main (only) purpose is for safety earth on the equipment cases, not so sure.


You could be right - but it made a worthwhile difference here at SiS towers on my Naim - I was well chuffed - it felt like an upgrade. I have a village overground supply, not sure whether that affects the amount of difference made.


I take it your conversion to TT was done for safety reasons Simon (additional Hi-Fi SQ enhancements a bonus). I’m not sure what amateur radio setup you have there but I suspect you have a very good RF earth (Tower ?) hence the conversion to TT for your property ?


It is for various radio setups including SW radio setups. I do have a SW tower but that runs its own separate earthing system primarily for lightning protection and (obviously) is no where near the house.
I do have multiple RF sinks - which are different length radials emanating from two separate points. The lengths are chosen to provide a low impedance path to ground at the frequencies of interest.
However I also use mains earthing on some of the larger RF linear power amps so I needed to decouple the PME and have TT. I was also having nuisance tripping with PME (again probably because of the overground distribution) and the distance to transformer/substation up a pole - well two poles actually… and TT dealt with that and got rid of the occasional tingles we felt in our ground floor bathroom with solid floor.

The water table is quite close to the surface at our property so we do get very ground conductivity most of the year round - so we really benefit from TT


Understood Simon - Makes a lot of sense in those scenarios.


I think that’s more or less what I was saying in " if this isn’t clean, then it must mean the supply to the house is also not clean"



Could it sound better because: “All metal components are treated with Furutech’s proprietary 2-Stage Alpha Cryogenic and Ring Demagnetization Process during manufacture that ensures the lowest achievable levels of distortion and noise”?


Hi Bob
Is this on your Olive kit?
Does the Graham’s Hydra improve the SQ over stock Naim cables?
Have you compared the Hydra to Powerlines or other makes of cable?


Also known as a zener diode :grin:


my father, retired head electrical surveyer built me an 8 way block using MK sockets all hard wired and star earthed with a couple of IEC jump out cables. The improvement over what I’ve had before that cost hundreds was very noticeable … took about an hour to build and test!