Mains Feed

[jimmymcfarrell]

I've been thinking about the idea of having a sperate mains feed to my hifi. Does this cause an improvement because you have no other equipment plugged into the same circuit, and therefore less noise in the electricity. However how can this work as the consumer unit will still be shared by all circuits, so mains noise could still be a problem. If the advantage comes from the fact that you use higher quality cable to the wall socket, surley most of these benefits can be gained from using a screened cable in the last few feet before the wall socket (from the consumer unit)? Any ideas...

 

[midlifecrisis]

I did this when I rewired my house, based on a number of articles that appeared in HiFinews a few years ago. You actually end up with a separate consumer unit (Hager recommended) for the HiFi spur, directly after the meter. It takes time to do, so you can't exactly A/B the results, but I'd say that while discernible, itwas not a night and day improvement - but I guess that depends on how dirty your supply was in the first place. Personally I'd say it's worth doing as I did, tagging on to a bigger wiring job at little extra cost, but not worth digging up your house to do as a standalone exercise.

 

[ergman]

Hi Jimmy
Yes it is definatley worth doing, your system will be considerably quieter and the results in the low freq will be very noticable, much more control and deeper bass,clarity,timing and seperation will all improve
But if your gonna do it then do it right.
If your consumer unit is split so you can add a trip fuse to the non protected side (the side that is not covered by your RCD unit) Your house lights and possibly your freezer may be on the unprotected side,then you will not need a seperate consumer unit.

You can use either a ring main or a radial there are huge arguments for both (i personally used a radial). But the most important thing here is to come directly from your unprotected side of the consumer unit from just one fuse fed directly to the wall sockets for your system, or the sockets you will plug your mains block into if you use one. Do not install seperate ring main or radials for different parts of the system i.e do not use more than one fuse in your consumer unit for lets say one ring main for the amps and one for the source components this is a big no no (unlike a big mistake made by a reviewer some years ago)

Absolutely everything in your sytem must be fed from one source in the consumer unit.
If you are going to go to this extent in your mains supply then i can highly recommend the Hi Fi or High Current woven ring main cable by Kimber it really is excellent. Otherwise use the lowest impedance cable you can find.
In your post you mention the last few feet of power cable being important. Well you are absolutely correct the last meter of cable into your equipment is paramount above any ring main or radial supply. But i also got excellent results from wiring my listening room with a dedicated radial.

Regards
ergman

www.manger-audio.co.uk

 

[themadhippy]

If your consumer unit is split so you can add a trip fuse to the non protected side (the side that is not covered by your RCD unit

But the most important thing here is to come directly from your unprotected side of the consumer unit

assuming you have calculated that the disconection time complies with the iee regs,section 413 is the relavent bit:MILD:

 

[HenryT]

Originally posted by ergman
Do not install seperate ring main or radials for different parts of the system i.e do not use more than one fuse in your consumer unit for lets say one ring main for the amps and one for the source components this is a big no no (unlike a big mistake made by a reviewer some years ago)

As far as I'm aware, there appears to be two schools of thought on whether this is a good idea or not. So why would this be a bad idea in your view?

In answer to the initial post on this thread, I believe impedence is the key is it not? A dedicated circuit for the hi-fi has fewer interconnections within it compared with a conventional household ring main which has several interconnections on it for each socket on that ring. Each interconnection increases impedence on the ring which is un-desireable, in particular for hi-fi equipment which has very dynamic current demands such as amplifiers for example.

 

[ergman]

As far as I'm aware, there appears to be two schools of thought on whether this is a good idea or not. So why would this be a bad idea in your view?

Hi henry
I will try to explain this as best i can, i have to translate this from some German text.

With all the hi fi components connected at one main outlet they will see the fluctations of the mains in the same manner, a common mode voltage interference only, that does'nt create voltage differences between the one or the other component.

As soon as you go to a different mains supply with one or another of your components you will then have a differential voltage between the components. This potential differential voltage will then try to equal itself via running through the signal cables ground. This then causes distortion or disturbances in the sound.

So when you install your mains supply from one outlet only you have far less voltage differentials.

Hope this helps
Ergman

 

[themadhippy]

whilst i agree that theoreticaly ther could be a diffrence in voltage between 2 circuits the amount will be so small that it wouldnt make any diffrence,however

. This potential differential voltage will then try to equal itself via running through the signal cables ground

bullshit,unless the equipment is faulty there should be no voltage to earth,running one device at 231 volts and the other at 230 volts wont result in 1 volt or even 1 mv appearing on the earth

 

[HenryT]

Hi ergman,

What type of wall socket(s) do you use in your set-up?

Henry.

 

[ergman]

HI Henry

The wall socket i use is a Russ andrews super socket treated with R5 and an added earth terminal cost me around £30.

I'm not sure if it was really worth it i did question them on the cost cosidering that really it is only an un-switched MK, which i have seen at the whole salers for as little as 50p.

But they said the labour in splitting the unit up to treat with R5 and fitting of the earth terminal puts the cost up.
I did compare it to a standard MK and it had definately been apart and re-riveted back together. So i suppose if it takes an hours labour to do you can see and extra £25 on there.

If you have more than one wall socket my advise would be to buy un switched MK's and treat them yourself with R5 or DeoxIT, i don't see there is any real need to split the unit.

Cheers
Ergman



www.manger-audio.co.uk

 

[HenryT]

Hi ergman,

I have a Russ Andrews modified un-switched MK wall socket too feeding my hi-fi. It's the version without the earth terminal and is part of one of the household ring mains at present.

I hear what you're saying about the expense compared to the wholesale version, and the potential savings rendered by treating all the contact/conductive parts with R5/De-oxit yourself. It does look a bit tricky, so I didn't mind pay that bit extra (I bought mine from a hi-fi show a year or two back and got a show discount anyway on the £20 odd price).

I remember seeing some rhodium plated unswitched (UK) wall sockets some time ago, although I can't for the life me think who the manufacturer of these were. Something in the back of my mind is telling me it was maybe Sonic Link, but then again maybe not? Very expensive though, at about £80 per double socket IIRC!