Power Supply for Listening Room

I am in the middle of a comprehensive house refurbishment which will involve the provision of a purpose designed listening room. We have both three phase and a single phase supply to the house. I was thinking of using just the single phase supply to the listening room on a separate consumer unit. Would that be the best approach or would it be equally as good to use one of the three phases?

Sorry, not directly DCS related but I do hope to include DCS equipment in the room after I have done some auditioning.

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Hi Murray. Welcome. Are you in the Us? Im not an electrical designer or engineer but im not certain i understand your question. What are you looking to power with this circuit. If you are setting up a separate subpanel for your listening space there are many good pages on how best to do it. If you are powering an air conditioner it would probably benefit from 3 phase power but you will need to ask your engineer what the equipment requires. It would be preferable to keep it separate and on your house panel if possible. I believe even euro spec 220v equip is single phase and i believe all us spec equipment is 110-120 v single phase. Do your research but i think most amps like isolated dedicated 20 or 30 amp single phase circuits. Periphery equipment can be ganged onto a good power cleaner on a single 20 amp dedicated isolated circuit. Give specs for your equipment to your engineer and have him calculate the electrical load. Make certain that your hvac engineer understands your equipment thermal load. You could quickly add 1.5 tons of demand to your ac requirement due to the heat from the equipment. Try to keep your circuits on one leg of the panel 110-120 v and have it grounded separately if possible. This will aide in eliminating ground loops and noise. Lighting and code outlets can be on the other leg. At least with my comments someone with real knowledge may take over. Good luck. B

Thanks you for your comprehensive reply, much appreciated.

Apologies for being unclear. I am in the UK and we are carrying out a very comprehensive refurbishment of an old house. We have an existing single phase supply and have installed a new three phase supply for the house itself and to cope with the air source heat pumps, for space heating only. We are not planning to have air conditioning.

We still also have the existing single phase supply with the option to keep it. My question is whether to use this existing single phase supply for a separate 20Amp ring main for the listening room equipment alone, or whether it would be better to dedicate one of the phases of the new three phase supply to this function and ditch the existing single phase supply.

I am planning this autumn to go and audition some equipment and DCS is on the list. I will also need advice on how to treat the new room which is quite large but an irregular shape. More about that later!

I hope that’s a little clearer!

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I’m UK based too. My dedicated mains is based on this:

That comes from Russ Andrews…

For the out and return cable I use:

For the mains socket, I use one of my own design that I used to sell called the Lens featured here: http://www.theaudiobeat.com/blog/roys_room.htm

Recently I had the mains cut-out fuse replaced and upgraded - the old one was decades old - and that was like a major upgrade for free! The installer was great and let me clean the fuse and contacts with DeOxite before installation!

Hope that helps



Thanks for that Paul, very helpful and plenty for me to pass on to the electricians.

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Regarding electricians, some won’t do as you ask because they will say it makes no difference.

There are one or two recommended on other forums who are also Audiophiles and go the extra mile to clean all connections, carefully route cables with neat cable management and won’t patronise you.

I used one years ago and he was a diamond. He was the one that did Roy Gregory’s room.

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The electrician actually carrying out the work is sceptical but the chap who owns the refurbishment company also uses a home automation and audio specialist contractor who agrees with me (and you!) so the electrician will do as he’s told!! I have given the contractor your diagram and he agrees we are both on the same page. Given the electrician’s work so far he is good at neat cabling, I will ask him to clean the connections, that should bring a smile to his face.

I have asked them to run the mains and then terminate in the room which is not yet fitted out and will await the choice of equipment and whatever room treatment is required. That will be a whole new adventure for me as I have never before had the luxury of a dedicated listening room, although the wife also wants a multi channel cinema system, so a challenge to incorporate both. I hope to be able to spend whatever time it takes to research and audition equipment this autumn and winter so we can have the room treatment installed early next year.

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You might want to consider installing a balanced mains unit or power distributor. Russ Andrews or Vertex have worked well for me.


Great news.

A little tip, something my electrician did. In the consumer unit is a neural bus bar made from low quality copper. He made up some nice jumpers of two parallel supra 2.5mm sq cables with ferrules at each end to replace the bus bar.


Many years ago I took Russ Andrews Ltd. advice and insisted my reluctant electrician installed the circuit as per the circuit otlined in Paul’s post @Paul. My installation used the lower cost Kimber Kable, MK silver plated sockets and MCB’s only on a dedicated ring main as opposed to multiple dedicated radial circuits (I believe Russ and his company still advocate using a dedicated ring main on a seperate consumer unit). To the best of my knowledge installing MCB’s only is no longer allowed under the current UK electrical regulations (circuits must additionally be RCD protected). Regardless I do technically approve of the use of https://www.russandrews.com/mains-installation/ using interwoven muliple conductor mains cable; inspite of the additional cable and installation costs.

Yes, do uses a specialist audio mains cable from the consumer unit, not huge domestics twin and earth as often recommended on other forums. I did that in the 80’s but we did not have anything like the radio frequency interference, electromagnetic interference and electromagnetic compatibility issues we have today that our audio system can pick up.

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Thanks, by coincidence the specialist electrician has already identified the Russ Andrews Superior mains cables, without my prompting, so we are at least speaking the same language. Do you know if the Process Q makes a big difference?

Good to know that your electrician is on board. Phew!

Regarding “Process Q” (https://www.russandrews.com/process-q-service/) , my honest answer is I have no idea. But given we are nut case audiophiles, I must admit I’d be tempted to give it a go! Stranger things have worked.

However, there was one thing someone told me years ago about commissioning a new mains installation, which is to plug in toaster or a kettle so there is high load (like 3 kW) and that it was a kind of accelerated burn-in.

I know, I have opened a can of worms! Oops.


Maybe a bit late in the process, but I thought I still add some of my own experience with dedicated mains connections for my audio system.

I have completely refurbished all the technical systems in our current home. This included an electrical heat-pump (well sourced), and extensive PV system and 2 charging connections.
I’m mentioning these explicitly because they all three noticeably affect the audio quality if no measures are taken.

We upgraded from a single phase 35A connection to a 3-phase 40A connection. We did not have the option to leave a 1-phase connection in place in addition to the new one.
I actually doubt if in your case the 1-phase connection is anything else than a split-off from one of the 3 phases entering your premises.

We have split the main incoming 3-phase connection into 4 groups: Solar, Heatpump, Charging and ‘the rest’. In addition to that I’ve made a separate group, directly split after the main disconnector, to feed my audio system. In addition to that we have a ‘regular’ group connected to the location of the audio system. This allows for easy comparison between the two, and splitting my AV equipment from my pure audio parts.

My key challenge was that every time the sun was shining, the car was charging or my heatpump was modulating, the audio quality would noticeably deteriorate. And I mean like walking into the room and thinking ‘what is wrong with my system?’. The all have one thing in common: they use inverter technology to feed or consume high currents into or from the grid. BTW my heat-pump is a Ecoforest one, which I choose specifically for its modulating capacity. There are heat-pumps that simply switch on/off. This high current + inverter technology just pumps heaps of HF noise into the the local grid. This kind of disappears in the all capacitive and inductive load further down the street. But so closely connected to the other equipment in my house it still ‘pollutes’ my power supply to the audio system.

Hence my quest to separate the audio system as much as possible, and as far down as possible in my home system. I’ve done this with the separate audio group which has a few ‘special’ components:

  • Hifi-Tuning fuse holder (basically an optimised Siemens Sitor unit) - hardly noticeable impact
  • Supra Lo-rad cable from switchboard to wall sockets - clearly noticeable impact
  • Furutech wall sockets & plugs on all cables - hardly noticeable impact
  • Audioquest Niagara 5000 filter/distributor - significant impact
  • Audioquest Monsoon and Blizaard cables - clearly noticeable impact compared with Supra and Audioquest NRG-4
  • Separate earthing pin close to the audio system - significant impact

When I say ‘significant impact’ this is clearly very much relative to the other options. It is comparable with upgrading audio cables, but not as big as for example my upgrade from my old Ayre preamp to a new one. Although the impact of the Audioquest Niagara was probably much bigger than I anticipated. In particular when I started to use it with a separate earthing pin and had figured out all the correct plug orientations.
I think that one and the long stretch of Supra cable (about 22m) have been the best investments.

Please note that from a regulatory perspective it might not be allowed to have a separate earthing pin connected in your country. We actually had to do specific earth-resistance measurements to have my installation contractor to sign off on this solution. But this was, in my system, absolutely worthwhile.

Hope this is of some use.


Dear Albert
Thank you for your helpful reply.
The single phase that we currently have is completely separate from the new three phase supply (and we will be paying separately for it). However, for reasons given to me by the electrician it is not possible to use this for the audio room because that would mean we have two earth points (it will be used to power some outbuildings). Instead, the plan is to use one of the new 20A three phases running to the main house which will be dedicated to that room alone, which overcomes the regulatory problem with more than one earth, which you correctly identify is not compliant in the UK. The separate supply will be from a separate consumer unit wired as per the diagram above provided by Paul. I don’t know yet if it will be possible to upgrade the consumer unit as he suggests (I am discussing this with the electrician) but I am planning to use the Russ Andrews Superior Install mains cable as suggested above by Brian. Fortunately for me our electrician is familiar with this product and the rhodium plated sockets, also from Russ Andrews.
The solar panels and heat pump will operate only on the other two phases, however, I will enquire whether or not they might interfere with the mains for the listening room, but so far I am told they will not.
Whether or not I will need to employ some further power conditioning remains to be seen and experimented with once the system is installed and up and running.
Thanks again, all contributions are welcome!

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I think you already have a much better starting position with your audio group on a separate phase than the solar panels and heat pump. That was not possible in my case because of the overall capacity requirements of both systems requiring the full 3-phase connections. There will always be some HF stuff getting into that other phase, simply because some of the wiring will run in parallel and there will be some capacitive coupling. But this will be quite minimal. And the aim to have any physical connection as far down the line as possible is well achieved in your setup.

I’m almost 100% certain that somewhere down the line (literally;) the separate single phase will be tapped off one of the other phases. Weather it is right down at the connection box of the grid operator in your house, or somewhere further down the street in a junction box. But that is not relevant for this topic.

I hope you can enjoy your new, solar powered, audio system soon!

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