Dedicated mains feed

I agree, 10mm, you only do it once. I have run 4 x separate 10mm T&E in trunking (one for each socket and therefore each black box). The lift in SQ was unfathemable (its only wire right). But you’ll be glad you did it. I now feed the P10, Aria, Nova, and 250DR from each separate 10mm run and the result is fabulous. Actually 10mm is not that difficult to work with, I’ve changed the routing (due to building extensions) several times and you get used to its demands.

By the way I replaced my Crabtree unswitched sockets for switched sockets (more for convenience) and it didn’t seem to make any difference…

1 Like

I’d be interested to know what MCB’s sizes you all ended up putting in the CU? 15 or 30 amps, or even less. The sockets would be rated at 30Amps, but you might lower that to get better equipment protection, although would a smaller fuse give less SQ? In the old days of fuse wire, a smaller fuse wire diameter might not be what you want when you have gone to the troubling of running 10mm, but I dont know how MCB would effect SQ these days?

Mine is 32 Amp, which again was Naim’s recommendation for my system. I know some use 50 Amp breakers. These are, in true Naim style, overspecced, which makes it all the more important to use (13 Amp or lower) fused plugs to protect the leads. Naim boxes then have another fuse next to the mains input to protect the actual device.

1 Like

Just looked as I’d forgotten but yes, 32 amp as per the diagram I used from another thread.

We have a 50 amp type C breaker in ours. I can confidently say that in 15 years it hasn’t tripped once. Given that the plugs and boxes are fused, it makes sense to me to have as big a breaker as possible. For what it’s worth, we have a single 10mm cable and then a MusicWorks 6 way block. It works well. When I was installing it Naim recommended a single radial and a block - a Hydra back then - so that’s what we did. The Rega with its SMPS is fed from the ring main.

I also have 4 x 50 Amp breakers and a 100 Amp Main Fuse which seemed to be the recommendation when this this topic was actively discussed 20 years ago. In that time no trips or problems even though I have rerouted several times. Incidentally, I never found a mains block to add any additional SQ over and above the separate mains feeds (and I trialled quite a few)…

1 Like

Hi all what sort of results did you notice when you swapped from house ring to a dedicated feed…

The obvious objective change was no clicks through the speakers when the lights were switched on. Musically, a more relaxed, open and dynamic sound. It always surprises me when people with big expensive systems don’t have dedicated mains. It’s just so basic, and so cheap.

4 Likes

32A is more than adequate for the MCB. Type C is recommended to prevent nuisance tripping with the Naim kit. The maximum size for your particular installation will be based on regs and safety. Your electrician, who will need to sign off the installation, will ensure it’s correctly sized for the cable between CU and socket and doesn’t exceed the current carrying capacity of the cable.

Agree it is cost effective … the issue for me is having the time … it will involve some tricksy cable routing - some major drilling and probably a redecoration of room… it will get done … hopefully in the next six months or so… currently I am running out of sockets … and if ever I get a second 555ps this will definitely mean a mains upgrade…

Cheap cheap or cheap in comparison to the Naim equipment in which it serves? May I be so bold and ask what you spent…? I’ve been pondering it for a while and will get some quotes. Our walls are essentially cardboard so routing and drilling will be relatively simple. The stack is also really close to the mains box.

I personally didn’t notice any clicks or interference from lights or appliances (so as you would notice) before the upgrade. The result after was just a lift in all aspects of SQ, as if a black box upgrade had taken affect is the best way to describe it. At the time it cost about £200 by a qualified electrician, but the was some 20 years ago. The regs have changed since so good advice to stick to a qualified sparkys advice.

2 Likes

…can you not take it outside the house? My routing went from one corner of the house to the opposite corner, using outside truncking and through the loft. Very little cosmetic redecoration needed…

1 Like

At a system of the level you have it’s a no brainer, albeit a bit more work than just adding another black box. I’d broadly agree with HH on improvements, the main one for us was the Plasma TV sitting on the same house ring the Hi-Fi was on. It did have quite a big impact on SQ, especially as we use the Hi-Fi for movies and TV sound as well as normal music listening duties - no issues now.

Whilst there is not a lot you can do about the incoming mains supply to your property, you can make the most of what you’ve got with a dedicated supply for the Hi-Fi. I’d certainly do it again if we ever moved.

For me, 3 x 10 metre runs of 10mm cable from new consumer unit to 3 unswitched MK Logic Plus double sockets, was around the £600 mark iirc. Work was done earlier this year. Worth every penny as far as I am concerned.

2 Likes

It was £200 about 20 years ago. The cable is 10mm2 steel wall armoured, which was not cheap at the time, running round the house under the flowerbed. The mistake made at the time was to daisy chain the earth for the hifi CU from the main house unit, which was a manly old 80s thing, originally a fuse box. About five years ago we had a new whizzy house consumer unit installed and at the same time I had the hifi earth taken directly to the meter cupboard using super thick cable. This probably made more difference than the original installation, which because of the earth was always, in hindsight, compromised. The better earthing has provided a silent background that can make recordings so much more enjoyable.

1 Like

I still have a buz from both power supplies for my pre and power amps which is audible above quiet passages and more so in a silent room. When I come into the room I can hear them from the door which is around 18ft away!

I’m wondering if this was the same you experienced before your re-earthing and if I should have this looked at again or is it just normal for this equipment?

Image of the earthing wire below, the smaller consumer unit to the right is the new dedicated one. As an update on price this cost £400 for a pretty long run under the floorboards in the cellar. Thankfully no exterior excavations were needed.

I must say apart from this buzzing the sound quality particularly the bass is astounding.

I’m not sure why you have so many earth cables fed back separately to the connector block on the incoming supply, but the main thing is that your hifi earth doesn’t connect via the main consumer unit, so I don’t think you need to worry about it.
If you’re still getting noise from your PSUs it could be DC offset on the mains supply coming into the house, which no internal wiring tweaks can change.

1 Like

Yes I can … and I will … I am on the 1st floor so it will go discretely and neatly under eaves in 25mm trunking which means moving around some existing cables. But then … my new feed will come into the room 1/2 way up wall … necessitating some surgery to bring cables to the correct point (I am not a fan of trunking!) (400mm off floor)… So yeah all relatively straight forward … but a complete pain … it will get it done. I will be getting all the gear in shortly.

Probably for protective bonding on metal pipework coming Into the house.

1 Like