Dedicated electrical supply

[davedotco]

Thanks for the input, guys. But let me rephrase my question: does one induce ground loops by using a separate radial circuit for the CDP, the amp, the settop box, the sat receiver etc? Is it better to use a common earth connection for all of them? Or is it of no importance whatsoever?

I might consider a mains regenerator (or balanced mains supply) should the mains appear to be very poor quality... but it is -- how shall I put this? -- not a priority at the moment.

Doc,

In an unbalanced system, the audio signal is referenced to ground. To make sure every device is using the same ground, it is usual to have ground carried from device to device using the screen on screened interconnects. If an 'earth loop' exists (more than one ground connection between two devices, taking a different route, then it is possible for current to flow along the loop, causing a noise voltage to develop between the two grounds. This noise voltage is mistaken for a signal by the amp, and amplified. In a domestic situation, induced mains is the most likely culprit and a ground loop is often characterised by mains hum.

In an ideal world, 'star point earthing' is used. A single point from which all signals are refenced and all earths come from. This is approximated in a modern system where the amp / AVR is earthed, and (usually) the other components are not earthed and rely on the amp / AVR as the star point.

As only the amp / AVR is usually earthed, your radial solution won't make any difference, but I would personally rather have all of the devices connected to the same supply, particularly as you have satellite / phone line connections which can generate high fault voltages in the case of lightning strikes or similar.

Are you sure every socket is being led back to the distribution board by a separate cable? That's a large amount of wire for no reason?

In my experience 'specialist' hi-fi equipment generally behaves as described by Andyjm above, it is the non hi-fi components thay cause the issue, TVs, satelite boxes and such. I f you go through the system logically this is not hard to work out.

There is no need to run multiple cables, a single run of twin and earth (30 amp 'cooker' cable ideally) hard wired to as many unswitched MK sockets as you need. Just make sure the earth at the fusebox end is sound.

 

[DocG]

Thanks for the input, guys. But let me rephrase my question: does one induce ground loops by using a separate radial circuit for the CDP, the amp, the settop box, the sat receiver etc? Is it better to use a common earth connection for all of them? Or is it of no importance whatsoever?

Doc,

In an unbalanced system, the audio signal is referenced to ground. To make sure every device is using the same ground, it is usual to have ground carried from device to device using the screen on screened interconnects. If an 'earth loop' exists (more than one ground connection between two devices, taking a different route, then it is possible for current to flow along the loop, causing a noise voltage to develop between the two grounds. This noise voltage is mistaken for a signal by the amp, and amplified. In a domestic situation, induced mains is the most likely culprit and a ground loop is often characterised by mains hum.

In an ideal world, 'star point earthing' is used. A single point from which all signals are refenced and all earths come from. This is approximated in a modern system where the amp / AVR is earthed, and (usually) the other components are not earthed and rely on the amp / AVR as the star point.

As only the amp / AVR is usually earthed, your radial solution won't make any difference, but I would personally rather have all of the devices connected to the same supply, particularly as you have satellite / phone line connections which can generate high fault voltages in the case of lightning strikes or similar.

Are you sure every socket is being led back to the distribution board by a separate cable? That's a large amount of wire for no reason?

Every socket, and every light bulb, and every light switch, and every electrically driven device (sunscreens, steam oven, ...). That's not an uncommon approach over here, and in our case it was necessary for the home automation. My electrician told me there is 20 km of wires in the house (electricity, UTP, speaker cable, ...) :shifty:

So will this 'star point wiring' give me 'star point earthing', avoiding the risk of earth loops?

 

[DocG]

That is usually all you need to do unless you have a poor main earth in your house, in which case you take the earth from the spur and run it to the best earth you can find, something like a water pipe at ground or basement level. If there is nothing obvious, get some advice.

Do not mess around with the earthing in your house, even if it is 'obvious'. Proper earthing schemes can be counter-intuitive as it depends on how the supply is configured by the utility, and water pipes and such like do not make good earths (the pipe is probably plastic from your stopcock onward).

I deliberately do not offer mains wiring advice on this forum, but in this case the advice is simple. Don't mess with the earth, get a properly qualified electrician in.

That's good advice. I'll ask my electrician. Thanks. :cheers:

 

[davedotco]

That is usually all you need to do unless you have a poor main earth in your house, in which case you take the earth from the spur and run it to the best earth you can find, something like a water pipe at ground or basement level. If there is nothing obvious, get some advice.

Do not mess around with the earthing in your house, even if it is 'obvious'. Proper earthing schemes can be counter-intuitive as it depends on how the supply is configured by the utility, and water pipes and such like do not make good earths (the pipe is probably plastic from your stopcock onward).

I deliberately do not offer mains wiring advice on this forum, but in this case the advice is simple. Don't mess with the earth, get a properly qualified electrician in.

Actually this is a very good point, whilst I am entirely comfortable doing the kind of work mentioned above, it is not good practice to offer advice to the unskilled or unqualified.

 

[DocG]

That is usually all you need to do unless you have a poor main earth in your house, in which case you take the earth from the spur and run it to the best earth you can find, something like a water pipe at ground or basement level. If there is nothing obvious, get some advice.

Do not mess around with the earthing in your house, even if it is 'obvious'. Proper earthing schemes can be counter-intuitive as it depends on how the supply is configured by the utility, and water pipes and such like do not make good earths (the pipe is probably plastic from your stopcock onward).

I deliberately do not offer mains wiring advice on this forum, but in this case the advice is simple. Don't mess with the earth, get a properly qualified electrician in.

Actually this is a very good point, whilst I am entirely comfortable doing the kind of work mentioned above, it is not good practice to offer advice to the unskilled or unqualified.

That's me! :cheers:

 

[davedotco]

That is usually all you need to do unless you have a poor main earth in your house, in which case you take the earth from the spur and run it to the best earth you can find, something like a water pipe at ground or basement level. If there is nothing obvious, get some advice.

Do not mess around with the earthing in your house, even if it is 'obvious'. Proper earthing schemes can be counter-intuitive as it depends on how the supply is configured by the utility, and water pipes and such like do not make good earths (the pipe is probably plastic from your stopcock onward).

I deliberately do not offer mains wiring advice on this forum, but in this case the advice is simple. Don't mess with the earth, get a properly qualified electrician in.

Actually this is a very good point, whilst I am entirely comfortable doing the kind of work mentioned above, it is not good practice to offer advice to the unskilled or unqualified.

That's me! :cheers:

Absolutely Doc, and not only that but you live in a country where wiring is clearly very different from the UK.

I may have a decent working knowledge of 'electrics' and be very aware of what I know and more importantly what I do not know but as has been pointed out, I am not qualified and absolutely should not be giving advice of this kind, even on something as informal as an internet forum so apologies for that.

One of the points I was trying to make, that I think is important, is to make sure everything that is connected to the hi-fi is plugged into that one spur, the other is that there may be some benefit in earthing this spur separately from the earth for the rest of the house.

Take advice certainly but bare in mind that minimising the noise floor on a hi-fi system may not be something that a 'regular' electrician is familiar with, his primary concern is going to be safety in this case.

 

[alchemist 1]

Just add new speaker cables and your at the promised land..........:shifty:

 

[RobinKidderminster]

Alchemy was outlawed for more than a decade

 

[alchemist 1]

Alchemy was outlawed for more than a decade

That's religion for yee............ray:

 

[toyota man]

I must say that before using this new circuit I carried out all of the electrical test required by the 17th edition of the iee rules and regs RCD times. earth loop impedance. insulation testing. earth continuety etc