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Dedicated Mains Supplies

Can we hear it?

[roots music touch the earth]
putting down roots

Product: Domestic electricity supply wire & copper rods & high quality sockets
Approximate cost: few bucks, maximum bang, especially if you get it wrong
Reviewer: Mark Wheeler - TNT UK 2013
Warning: do not conduct any experiments on any mains wiring.
Do employ a qualified registered professional electrician to make any alterations to your house wiring.

This is the sequel to the article Ground Force Zero and will only be useful after reading that first. The old scribe's dedicated music/audio room is complete and boasts a new ring main exclusively for the audio system after this proved in tests to be superior to spur and hydra arrangements. The reviewer's life involves numerous changes of position and arrangement of equipment, so one cluster of sockets cannot be relied upon to supply all permutations and combinations. The room's balance of reflection, absorption and diffusion is ideal, the modes are well controlled and the mains quality will be the final refinement to exploit the full potential of any component under test.

We begin with the premis that a separate ground/earth-rod/spike/stake tying down the earth potential of the audio spur is a cost-effective addition to the existing ground/earth arrangement. In many places, including the UK, this planet is also the return path for the generated electricity phases and the defined 0V condition. To work effectively, a suitable damp location has to be identified for the rod or spike. Parched dirt is not useful at all. The words earth and ground, while simultaneously referring to an electrical definition also refer to the planet we stand on. This does not mean that any old bit of the planet will be good enough. The windswept hillside inhabited by your old scribe soon dries out, despite heavy local rainfall. Deeper sub-soil is difficult to reach due to rocks near the surface. This cottage does have a cellar where the soil under the floor flagstones never fully dries. Unfortunately this is an 8m cable run from the system side of the music/audio room. The low cost of a mains spur compared with other upgrades justifies the use of exotic materials in places. Standard earth cable (solid core copper or a few thick strands, depending on gauge) is reputed to perform poorly at RF, which is precisely where we are looking for local improvement. Hence it is worth investing in Radex cable for this task. However, for the earth connection to the distribution unit (the box that used to be named the fuse box) good quality standard 6mm^2 twin and earth cable is used to comply with regulations and fit into the distribution unit terminals and interior space.

I repeat from Ground Force Zero, employ a qualified electrician to perform this task, otherwise your audio dedicated earth/ground rod/spike could end up as the direct path to earth/ground for your whole street in an electrical storm.

The best quality distribution unit large enough (6rcd+6rcd+3non-rcd) for the house is installed and the internal layout chosen to minimise mutual inductance. The house has solar panel electricity generation and the inverters produce substantial RF and high frequency AF. When first installed, before the audio ring, the solar panels affected audio quality in direct proportion to the amount of sunlight. This was tested by isolating them during listening sessions and reconnecting them. Installing the audio spur connection as close to the meter tails as possible partially mitigates this problem. Ferrite chokes on the inverter outputs before they enter the house render them almost inaudible.

The ring comprises 6mm twin and earth to and from the distribution unit to two clusters of sockets, to enable options like sources and pre-amp at one side of the room and active loudspeakers on the other side of the room, for example. The two clusters of sockets are linked by 10mm^2 twin and earth cable taking the shortest possible route under the floor, laid before the thermal mass floor was poured. None of the cables run close to or parallel with other mains wiring installation, except for the final 3m into the distribution unit. Layout was determined by trial and error.

The socket clusters are on flying leads of Black Rhodium silver plated copper audio mains cable of the type that came out well in Ben Duncan's tests for electrical and audio quality. The sockets themselves are not audiophile unobtanium, but the best MK range. The terminal quality stays bright, is self wiping and has good spring strength.

[dedicated earth rod]

Installation Summary

Location and logistics do limit the options for most dedicated audiophile mains supplies and the options chosen to be installed were selected from trials of what might be possible in this location while complying with local regulations.

  • Dedicated ring main for audio only
  • Two clusters of sockets on Black Rhodium flying leads hard wired into the ring
  • Lower noise cluster at source/pre-amp location, achieved by Radex connection to a top quality 1.5m earth rod/spike.
  • Second cluster at active speaker location
  • 4m of 10mm^2 twin & earth connection with Radex duplicated earth cable between socket clusters by shortest route under floor
  • 8m Radex earth connection from pre-amp/source socket cluster to earth rod in cellar adjacent to soakaway drain
  • 6mm^2 twin & earth connections from both socket clusters back to distribution unit
  • New distribution unit
  • Audio ring connected to non RCD connection closest to meter tails
  • Solar panel inverters connected to same non RCD connection as required by local practice

Sound Quality

The effect of the mains wiring upgrade is obvious. It is not obviously like a better source, or better amplification, or better loudspeakers. It is like a modest upgrade of all elements of the system. Clarity is improved like better tweeters. Bass and rhythm is improved like a better source or better amplifier power supply. Transparency is improved like a better amplifier. It really is that simple.

Surprisingly, the soundstage also opens up. It is wider and deeper, extending further beyond the loudspeakers. There seems to be less audible murk between individual instruments, enabling them to be more clearly identified and their contributions followed. Vocalists seem better delineated from the instruments and from each other.

This has been checked with all the available equipment over a full year, including the review items passing through. Sadly there have been no active loudspeakers so the effectiveness of the two socket cluster link has yet to be properly evaluated. However, a single stereo power amplifier connected via the second socket cluster sounded the same as when connected to the same cluster as the pre-amplifier. The improvement is noticeable at any time of the day or night, with any weather conditions outside, including sunshine generating electricity at the solar panels. The difference between times of peak demand for electricity (e.g. weekdays at 18:30) and low demand (e.g. Sunday at 1AM) seems to be less obvious. However, this is a subjective judgement relying on audio memory and therefore barely justifies the effort to type it.


For the cost there is only one audio upgrade comparable. Vibration control also offers a great bang for your buck. Mains quality clearly affects sound quality, and a metre of fancy wire between socket and amplifier, if it has any effect at all, will not have a fraction of the effect that a dedicated mains ring or spur will have. The metre of magic unobtanium wire may even cost much more than installation of a dedicated mains supply. Both vibration isolation and and mains quality have profound effects on domestic music reproduction.

An amplification stage is nothing more than a device to modulate the power supply according to an input signal. The power supply quality starts with the mains input.


Some paragraphs of Ground Force Zero bear repeating:

Warning: do not conduct any experiments on your mains wiring.

Here are descriptions of the various arrangements in UK mains wiring so you can correctly specify work to your qualified electrician. Please note that in the UK Building Regulations Part P requires, in England and Wales, that only certified persons can carryout electrical installation work, or the work must be 'Part P' certified upon completion. However, although "minor works" may not require 'Part P' certification, the installation of whole new circuits do not qualify as 'minor'. New upgraded sockets or "Installing additional earth bonding" are permitted "conditional upon the use of suitable cable and fittings for the application, that the circuit protective measures are unaffected and suitable for protecting the new circuit, and that all work complies with all other appropriate regulations". My advice is to get everything tested by a qualified electrician. Your old scribe gets to be old by hiring qualified professionals rather than frying himself.

It IS YOUR RESPONSIBILITY TO CHECK ALL FACTS BEFORE embarking ON ANY WIRING CHANGES, new installations or alterations to existing installations. You have been warned.

Music enjoyed while writing this review

  • Rolling Stones: Beggars Banquet, recent 180g audiophile reissue
  • The Linndrums: Same Old Claptrap, more dull repetitive material from Ripoff Records LM-2
  • Lieutenant Sparrowhawk; Lieutenant Pigeon Pie, indigestible granny's piano
  • Captain B. Fart: Tribute Mask replicas, unlikely tribute act without a bandwagon to stand on
  • Major Cat Astrophe: Unsafe as Old Milk, equally unlikely tribute act
  • General Malaise: Unwarranted Conditions, surely the nail in this existential tribute trio

Copyright 2013 Mark Wheeler - mark@tnt-audio.com - www.tnt-audio.com

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