Hardwired Balanced mains transformer installation...great improvement!

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Having heard a balanced power supply in my system at a AOS get together at mine, the upgrade to my system really made me realise what my next step was. It really was a no brainer. Balanced power suplies work and they work really well.

I didn't realise my mains was so bad and how detrimental an effect this can have on your hifi system's sound - mains is VERY important guys!

With this in mind I decided to "hardwire" the balanced mains unit into my property rather than buy a standard Mains Unit with 13A sockets that you plug in like a distribution block. My thoughts were to "Do it once and do it right": the hardwired approach would allow a much more direct connection between my hifi and the balanced mains and in turn my mains supply.

Understandably this was a far more serious investment than swapping out a set of cables or even plugging in a "standard" balanced mains unit, which effectively is just a very fancy mains distribution block.

No, what I was proposing in my system was more hardcore and potentially more dangerous too.

It was important therefore not to take the safety aspect of this installation lightly, and I had researched on various forums, read up on UK electrical safety and had the ear of an expert in these matters who advised me on things I wasn't sure about. Additionally all work was inspected and ok'd by an electrician before I even switched on.

I am not offering any electrical advice...this post is really just for illustration of what I did in my own system.




Note the 2 circuit breakers - important! MCB on the input and RCBO protection on the output - safety first!



Think of wiring a plug, Live Neutral and Earth..right?

Exactly the same principle here. The Transformer has TWO sets of internal terminals, 3 in each set for L,N and E)

INPUT TERMINALS: Taking the 230V feed from the wall socket/Ring Main

OUTPUT TERMINALS: Outputting the "balanced" output from the transformer to your equipment.


The output cable from the transformer could be terminated in several ways; one or more 13A sockets...could wire in a mains distribution block in...or (IMO) the best option, a hard wired "Hydra" type junction box. (I show how I construct this later)

You'll notice in that last picture that there seems to be extra green/yellow earth wires coming from the earth terminals?

That is becasue the case of the transformer needs to be earthed too, not just the equipment attached to it.

There are various "earth points" attached to the inside of the case, basically copper bolts screwed on, which makes sure the case is effectively connected to earth and therefore safe.

These bolts came in very handy when wiring up the individual mains cables internally at later stages of the install.

When making up mains cables, as Illustrated HERE:, you want to connect up the cable shielding to earth at the plug end to send any EMI or RF picked up by the cable to earth and stop it from affecting sound quality.

But if theres no plug and its going into the mains transformer...what do you do with the shielding? How do you channel away the EMI/RF?

Thats where the earthing posts on the case of the transformer comes in, after preparing it properly you just attach the shielding to earth.



Cable Shield gathered as strand, heatshrinked and tapped into earth point on transformer case.



Normally you would just plug these things in, and you would be able to switch it on and off at the plug switch. My Balanced transformer had two switchable circuit breakers which completely cut off the power to ANYTHING connected to its output and input terminals. These breakers, effectively, functions as the aforesaid plug switch and allows local termination of supply and are properly fused with MCB/RCBO protection. With this safeguard in mind I decided to continue maximising my mains potential. If it were possible I would have run seperate spurs from my consumer unit to my hifi system, but as I was unable to do this for practical reasons I looked to the next best option. I wanted to get as close as I could to the ideal for my situation, so I "hardwired" my balanced mains into the ring main instead of just plugging it into a 13A socket. Instead of the ring main wires (L,N and E) being internally connected to a double 13A socket, I connected up the wires internally to a 60A terminal block, which in turn I connected to the input wires feeding the Transformer. These connections were verified for safety and were neatly hidden away inside the patress behind a blanking plate. This blanking plate replaced the 13A double socket and allowed a neat entry point for the Transformer input cable.



ITS STARTING TO COME TOGETHER - INTERNAL WIRING ALL DONE (I run two systems off the balanced mains, hence the Belkin mains block)



Rather than fitting a mains distribution block at the output of my Transformer, i decided to remove all the unecessary breaks in the cable which could affect sound quality and again hardwire as much as possible. Based on threads read here on AOS I initially planned "star earthing" all earth wires from the mains cables coming from my kit. Research dug up that this was a preferred way internally wiring mains distribution blocks (I believe MCRU and Mark Grant do their blocks this way?), but FURTHER research showed that the benefits of bringing the common wires together at a single point could bring advantages not just for earth, but for Live and Neutral wiring as well. Nordost in fact employ this star construction in their "Thor" mains block (£1600!!:stalks:) so the theory must be sound.

(At this point I must show grattitude here to a certain Roy K. Riches for the invaluable information he gave freely on constructing the junction box and other mains related information)

Think of a 13A has three screw terminals for the three wires in a mains cable.

The junction box uses that exact same principle except it combines more than one cable for each screw terminal, all same coloured wires go to a central point, all insulated from the other two terminals.

IT WAS ALWAYS A CASE OF SAFETY FIRST So I had to decide on a British Standards compliant electrical enclosure for the junction box, and the correct rating of internal screw terminal blocks for the internal wiring. I did my research, bought in my parts and started constructing:

IP55 BS COMPLIANT ELECTRICAL ENCLOSURE (Note the side entry holes for the different mains cables)


Two pieces of wood bonded to electrical enclosure using "no more nails" - ROCK SOLID electrically safe base for constructing the internals of the junction box.

(Upper piece of wood cut into U Shape to better physically seperate the three different electrical screw terminals)










I run a Belkin PF30 mains conditioner in my system, which I found to have been an effective way to help minimise the damage inherant in some of the switching power supplys used in my sytem, Tivo box, Routers etc.

Looking for a way to incorporate it into the balanced mains I decided to hardwire THAT into the junction box and any equipment with switching power supplies...? Plug it into the Belkin!

Hopefully this is an effective way of isolating the switched mode power supplies from the "important" pieces of my hifi; the amp, Dac and Server.

Whilst I was there I decided to remove the captive lead on the Belkin and hardwire a far better quality of mains lead to it, in fact the same 4mm Sq cable I was using elsewhere in the install. I was never convinced that it was a good idea that something proposing to be a mains cleaning product was fitted with what to me seemed a sub standard mains cable.

So out with the old cable and in with the new one, some pics:




So...all wired up, safety tested and ready to go. :)

In my experience a new DIY mains lead can take some time to fully settle down and get its final sound. In the case of this install, there were so many variables; a new balanced mains transformer, new cables, many many new connections and terminal wiring etc that I just never even thought about it. I decided to just switch it on and enjoy it. :)

I did make a point though of doing everything at once so that any cable burn in etc would happen at the same time - across the whole setup.

The sound right from the get-go was very obviously better - a LOT better than it was before plumbing in the hardwired balanced mains.

Noise floor just about vanished. So what does the noise floor sound like? Dunno..but you now its gone when its gone; everything is more dynamic sounding, more detailed, but (and this is the best part for me) with a more natural sense of timing and the music having "space" to do its rush, no hurry..just music. Its MORE than just the 3am sound quality during the day cliche...balanced mains brings something really special to the table.

I had heard just how bad my mains quality was when Ali Tait brought his own balanced mains transformer over to mine for a listen. Massive improvement - and his was the type that you plugged in and had two 13a sockets for equipment that we plugged a mains block into.

That first morning of switch on my own BPS installation sounded at least as good as what we all heard when Ali brought his over. I would say that over the last couple of weeks its got noticably better.

Hands down its the best upgrade EVER in my system, and I've had a couple of major upgrades that the rest of the visiting hifi mates noticed at the same time.

But these were not as obvious and improvement as plumbing in the balanced mains.

I really feel hardwiring was well worth it. A lot more work sure, but I will have ended up with a mains system of a lot less impedance feeding my hifi system which has resulted in a fantastic upgrade.

Even my Plasma TV and Tivo has taken a leap in quality, watching 1080p bluray rips on the server is fantastic.

Want to thank some people who really helped me in getting this done, credit where credit is due.

Ali Tait, who advised me on balanced mains systems safety, particulalrly with regard to the scaremongering I had read online about equipment becoming live if an electrical fault condition occured with the transformer - I customised my Airlink Transofrmer with RCBO protection on the secondary power leg..totally safe.

David Brook of MCRU, who advised me on cable choice and let me try a few samples of cable before I finally wired it all up.

An unabashed plug for genuinely the two best mains leads I've heard for sensible "real world" money. Previously I was using LAPP as my go-to cable, as I had made up Rega mains lead clones using the same stuff Rega did and I couldn't see past it for sound quality.

This new stuff David let me try was a lot better than the Lapp, so much so I'm done with mains leads...

I used this stuff mains spur cable between wall and transformer (6mm x 2)

and this 4mm x 2 for my mains cables.

And Roy K Riches, who's information was invaluable when I was researching all this stuff, getting over the worry of doing the is MAINS ffs!!!

...and I cant leave out Richard Dunn and the guys over at Hifi Subjectivist forum either.

His advice on the more "extreme" mains fettling gave me a good sense of perspective on the whole thing and for a lot of the stuff he said he wasn't wrong.

As I said at the start, mains quality can make SUCH a massive difference to how good your hifi sounds. If you have excellent mains quality already in your may not get as much milage out of it as I did, but in my case it's (yes, here it comes...) night and day.

Interstingly enough, there was a debate about balanced mains vs mains regeneration?

I have heard an Power Inspired AG500 mains regen unit in my system before the balanced mains was put in and yes, the Ag500 improved the sound. It was subtle though, unlike balanced mains which was immediate, obvious and made me grin like a loon. :)

I got all the work checked by an electrician before I hooked it all up and switched on, so I feel confident I can just enjoy the music.

If your not a qualified electrician, and you want to hardwire into your mains, get a professional in to advise at least. Safety first.

I hope this might be useful for someone, to me its a no brainer upgrade. Makes the best of the kit you have.


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nice work gary , had a lend / use of a mains conditioner last week , I will admit to being almost a disbeliever , but :shock: its on my saving up list .

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Good job,I have used an Airlink CBS 2000 tranny for a few years now,after trying various other conditioners and the Airlink is by far the most effective I have tried.

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Super Wammer

Rep added for all the hard work both in the installation and the post. Well done Gary, enjoy

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Interesting stuff. Good on you for thinking about it and doing it.

One query: How is that fat cable secured to the plastic cover plate? It looks like the only thing properly connected there is the chocolate block itself, with the heatshrunk cable just wedged in the too-small hole from the outside :shock:

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Fundamentally it's a very good idea. However, there are a couple of points that really do need to be addressed.

If that was checked by some sort of electrician, then he/she needs a visit to Specsavers, for one fundamental point. In all the pictures, you show mains cables being passed through holes without a suitable grommet and without any physical means to prevent the cable being pulled out by accident.

The obvious point here is that the first thing in the line is a transformer mounted in a metal box, to which all the subsequent grounds are connected. The grounding and the MCBs are excellent. However, I give you a simple (and perfectly possible) scenario. You trip over the supply line and it pulls out of the internal connections because it isn't physically secured. Possible result? The live cable touches the case. There is now no connected grounding from the supply and all of your equipment now has cases that are live.

Standard item for PAT testing and similar is that supply cables must be physically secured so they cannot be pulled out by force.

Sorry, quite possibly you've done this afterwards, but if not, you need to.

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Thanks guys.

Yup, was a fair bit of work getting it plumbed in, but the fundamental improvements in sound quality are well worth the effort.

Highly recommended :)

The photo's were taken as i was going along, all the cables were clamped off solid on the final install.


The fat cable going into the wall plate was clamped inside the plate, its rock solid and cant budge.

It only looks that thick becasue of the braiding, its 6mm x 2 3 core cable.


I hear you on safety mate,

the cables were all clamped solid before it was signed off.

The only grey area according to the spark regs wise (but still should be ok), was that each entry to the ring main needs to be switchable locally and as I was removing a switched double socket and hardwiring using a 60a chocolate block, I was taking away that ability.

The trannie itself though has SWITCHABLE MCB and RCBO breakers on the box itself, so he says these act as the switch at that local point.

Regarding tripping over an unsecured wire, I hear you on safety, all wiring is out of site hidden behind equipment racks.

Its not possible to access the transformer, wiring, junction box without physically moving stuff out the way.

This piccy hopefully illustrates what I mean:


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reggie is right, hes mental, lives in a tree, has crap speakers, no way can he tell the difference, so for him there is no difference. Fine.

OP wouldnt have gone to all this hassle if he hadnt tried the kit out first and thought it worthwhile.

"Horses for Courses". Ive said that a few times recently, no doubt I'll get slagged off for saying it again.

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Wouldn't you have been better off putting the money into new speakers, or a decent carbon-frame bike?

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Super Wammer
A pointless exercise. The mains supply can have no effect on sound quality.

Ah! now I see why you go by the name of "Mental" :cool:

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