|
|
Post by Admin (Rob) on Jul 31, 2014 9:28:46 GMT
How can a length of wire just one metre long carrying mains electricity make any difference at all to sound quality?
Ah, that is the perennial question asked by many, but there is an answer.
A mains cable is there just to carry electricity from the wall socket to your components, right? Yes that is true and all of them do that job reasonably well. But, when it comes to high current delivery, most cannot cope with instantaneous high demands and restrict that flow, especially with amplifiers even of modest output capability.
To get back then to the notion that the cable simply carries mains voltage from the wall socket to your components without spilling any on the carpet in the process, an inexpensive cable rated up to 3 amps will do the job perfectly well, but when presented with a much higher SHORT TERM demand it simply heats up through it's resistance rather than responding to that additional instantaneous demand. This is manifested in the sound you hear, particularly so by flattening out bass notes and sounding boomy with overhang, sometimes midrange clarity too is also similarly affected. So, by replacing that notional 3 amp power cable with another that can handle 30 amps or more, you then take away that particular bottleneck. Still with me?
Fine, you may say, but what about the many miles/kilometers of wiring between the power station and my wall socket? It has to travel across the entire national grid system and through several transformers too. Surely in that context, my 1 metre length of cable isn't going to make any difference at all? In actual fact, it IS that final metre or so which is the most, not least, relevant. Especially so when behind that wall socket there is likely to be 4mm of solid cored copper and the wiring from the incoming fuse box/consumer unit will be considerably thicker, so 1.25mm or less of wire inside the generic 3 amp mains lead HAS to be the weakest link in the power input chain.
INSTALLING AN UPGRADE MAINS CABLE ISN'T "ADDING" ANYTHING AT ALL, BUT IT IS TAKING OUT OF THE SYSTEM A LESSER QUALITY CABLE THAT THAN CAN BE BETTERED.
Conductor material, gauge and quality also makes a difference. Copper comes in many grades and not always the best quality is to be found in generic cables. A pure copper cable will sound 'better' than a low grade copper one. A heavy gauge copper cable will sound better than a thin gauge copper cable. A pure silver wire mains cable will sound better than a copper one.
Connectors too play an important role in sound quality. The overwhelming majority of mains plugs in a domestic environment are made from brass. Copper is better still, silver plated copper better still and pure silver best of all but the cost of that is rather prohibitive.
TO BE CONTINUED . . . . . .
|
|
|
|
Post by justchillin on Aug 3, 2014 18:42:29 GMT
I am using Nordost Shiva mains cables and it has always puzzled me how they can change the sound for the better. Not sure if the explanation above is 100% correct but it is some kind of answer to the mystery.
|
|
eldorado
Junior Member
Posts: 51 
System components: Marantz CD17, Luxman A-357 amp, Proac Studio 140 speakers
|
Post by eldorado on Aug 4, 2014 13:21:09 GMT
Fine, you may say, but what about the many miles/kilometers of wiring between the power station and my wall socket? It has to travel across the entire national grid system and through several transformers too. Surely in that context, my 1 metre length of cable isn't going to make any difference at all? In actual fact, it IS that final metre or so which is the most, not least, relevant. Especially so when behind that wall socket there is likely to be 4mm of solid cored copper and the wiring from the incoming fuse box/consumer unit will be considerably thicker, so 1.25mm or less of wire inside the generic 3 amp mains lead HAS to be the weakest link in the power input chain.
Are we talking about total AC loop resistance here between wall socket and local sub-station then? |
|
|
|
Post by Admin (Rob) on Aug 4, 2014 20:49:51 GMT
]Are we talking about total AC loop resistance here between wall socket and local sub-station then? We are indeed |
|
|
|
Post by Admin (Rob) on Aug 9, 2014 17:15:28 GMT
Could someone please explain to me what AC ground loop is? I seen the phrase here and there but don't understand it. I'm hoping it isn't applicable to my system because I have conditioners and upgraded power leads could someone throw some light on it please. Thanks A ground loop is where it is not beneficial to have two earth point contacts. Just disconnect one earth and route the wires so only a single earth point is made. As you seem to run all your components through the Isotek conditioners it's not going to be an issue for you. |
|
|
|
Post by justchillin on Aug 10, 2014 7:27:55 GMT
Happened to me years ago when I bought a new phono stage it hummed like crazy and I was going to return it to the shop but a friend told me to disconnect the earth wire on the power supply. Hum gone  |
|
|
|
Post by Admin (Rob) on Oct 11, 2014 14:46:00 GMT
I have been considering upgrading my 2 double mains sockets to unswtiched Rhodium plated sockets then that led me to start thinking it wouldn't be hard(live in a bungalow so its a dodle for wiring) to take those 2 sockets out of the existing ring main reconnect the existing ring main, then create a new separate spur/ringmain with upgraded cable(between HiFi sockets and consumer unit) from MCRU so that the 2 sockets which power the HiFi would have a dedicated spur/ringmain with a decent cable instead of the standard 2.5 twin & earth Anyone got any thoughts Glad you asked this question Trev as I have been reading about the benefits or otherwise of ring mains. The article said that a spur is much safer than a ring in a fault condition, as the spur has only one live and one neutral (plus earth of course) to isolate under fault conditions, whereas a ring is being fed by two live and two neutral conductors from the same point on the fuse board. Under normal safe usage of course, the ring main can supply twice as much current, which isn't really a priority for feeding your system. On the continent and the rest of the world in fact, none of them use a ring main circuit, it is entirely individual spurs feeding back to the central consumer unit/fuse box. Anyway, back to your question; I would do as you suggest by reconnecting the ring main into a separate circuit minus what feeds your system, then add a dedicated spur on it's own from the consumer unit with the MCRU wire to a switchless wall socket as you intend to. A single spur then works out cheaper than a double run to create a new ring and the wire gauge is more than adequate to supply the power for your system |
|
|
|
Post by Admin (Rob) on Oct 11, 2014 19:23:42 GMT
Yes as I understand it a ring in 2.5 twin and earth can carry 32 Amps and a spur with the same cable can carry 20 Amps I believe if you increase the 2.5mm to 4mm on a spur it then increases back to 32 Amps max load I think. It's interesting what you say about the rest of the world because I had always thought a ring was better than a spur but glad I'm wrong because as you say it then reduces the amount of cable required which normally isn't a issue with normal 2.5 twin and earth because it's so cheap but when the cable in question is more expensive the amount needed then starts to becomes a factor. Regarding the cable I will need a approx 9/10m run of cable from hifi sockets to consumer unit I have a budget of £200max (so £20 max per meter) on the MCRU page there is 3 to choose from within budget I'm interested to know which one you would choose(9.95/14.95/19.95) flexibility is also a concern because it will have to drawn up/down through the existing flat oval conduit which is plastered into wall from ceiling/loft down to the 2 double sockets Naturally, the 10mm2 cable (£19.95) should be the best performer and if you are going to do it then do it right first time. However, it is a rather large diameter and somewhat unyeilding cable at the end of the day and if it won't fit into your conduit then you are stuffed  My advice would be to ask Mr MCRU to send you samples of a few of inches of each cable to make sure they are going to fit into your channelling easily, as flat oval doesn't have much room to play with. I would rather do that than buy the 10 metres off bat and find it won't fit. Looking at the pictures on the MCRU website, the £9.95 (4mm2) cable has an inner and outer jacket with the metal woven braiding sandwiched in between. This means you could discard the outer jacket and the braid which will dramatically reduce the diameter of the cable without affecting it's performance. Similarly, the £19.95 10mm2 cable looks as though it also has a similar build to the 4mm with an inner and outer jacket, so that too could be stripped down to reduce the diameter. Before you go weak at the knees at the thought of removing the metal braiding, let me say that none of the cables I see there have a total coverage weave pattern to begin with and secondly, in terms of EMF leakage, copper or steel braiding makes no difference whatsover to controlling what radiates outwards from the cable anyway and even less preventing any external RFI source from entering the cable either. RFI would have to be strong enough to heat up your teeth fillings before it could penetrate a mains cable (ask any matelot who worked in close proximity to a radar array). The reason why they have a "loose" weave metal screen is effectively resisting damage to the cable by objects like spades or cutters, in other words mechanical protection rather than electrical protection. As they are going to be tucked safely inside conduit behind plaster this should not be an issue. |
|
|
|
Post by Admin (Rob) on Oct 15, 2014 14:39:03 GMT
I have found the conduit from living room sticking out from ceiling in the loft and it measures 10mm so that is my maximum size for the new cable and I was right in saying currently it has 2x 2.5 twin &earth in it That proves you are right about the 2 x 2.5mm T&E Trev and we now know the maximum diameter of cable that will go down the conduit, but that of course is assuming there are no kinks all the way down to impede feeding the new cable down it. Do you know the outside diameters of the new candidate cables? I would imagine that the 10mm2 is going to be too large, even with the outer sheath and braiding removed. |
|
|
|
Post by Admin (Rob) on Oct 17, 2014 19:06:49 GMT
No I don't know the diameters of the cables yet I have not spoken to MCRU yet my spark is not here next till another 7 weeks so I'm in no rush I have time on my side . I'm pretty sure there are no kinks in the conduit because its 1 run straight up from the sockets and the fact that I found the top of the conduit in the loft means that it is conduit all the way up I feared the conduit might of stopped at the underside of the coving in the living room which would of meant the top/last 6/8 inches may of been tricky with a large cable but I'm pleased to say I found the top of the conduit in the loft so it should be just a 7ft upwards run up the wall into loft and I'm sure when I put the conduit in when me and my spark rewired the place I used a single piece of conduit with no joints in it so there should not be anywhere for the cable to get caught up on. On the face of it it should be a doddle to do its even easier once its in the loft I cannot see anything which could make it a tricky or awkward job as long as I don't get a cable thats too big and if i do that when I know the conduit size I would need shooting  Sent a email to MCRU and he recommends I use the Belden 83803 cable which on his website is 11.95 per 0.5m I assume that Mr MCRU has measured the Belden cable or already knows that it will fit into your 10mm conduit no problem. He is pretty good at checking these things and if not I believe he provides excellent back up. |
|
|
|
Post by Admin (Rob) on Oct 17, 2014 20:41:06 GMT
I assume that Mr MCRU has measured the Belden cable or already knows that it will fit into your 10mm conduit no problem. He is pretty good at checking these things and if not I believe he provides excellent back up. Yes he was aware of all the facts regarding conduit size etc and i asked him what he recommended and his response was "I suggest belden 83803 as its quite thin but has foil shielding so very good for shielding" So unless anyone can suggest anything better for the job I will be ordering it from him soon along with the 2 Rhodium plated double sockets Belden 83803 is rated at 12 AWG which is around 3.31 mm2 per conductor with a Teflon insulator. Although I cannot find the outside diameter measurement anywhere on the net, then I trust Mr MCRU has done the necessary and measured it. There are of course "better" cables, BUT they normally carry a much weightier price tag and of course have a bigger diameter, so the Belden appears to be the best fit compromise Trev. |
|
