Power cable construction/shielding

Filipedine

Hi All,

It's not an easy topic to talk about and lotes of different opinions.

Shielding on power cables are used by many cable brands nowadays and a wire that gets out of the wall, has more probability to pickup noise form WiFi, BT, EMI, etc... than it did some time a go. Some of this interferences can be reduced/eliminated by the isolation materiais used on the cable and by the way the cable was bulit.

I don't know if there is a ISO standard for the conection of the shielding layer, bet there is...  probably we Will find when and not to use it.

Thanks for your input

Filipe

BlueWizard

The underlying point is - What good is 1 meter of Shielded Cable when it is connected to MANY Meters of unshielded wire inside your walls?

Still, if that is what you want - Shielded Power Cable - more power to you.

Steve/bluewizard

Calsun

Any good device is going to be engineered to deal with the power from the grid. If the voltage level varies to much than something like an ONEAC line conditioner is important but otherwise the PSU design will allow for voltage fluctuations.

What was common years ago but seems to have been forgotten is the value of adding a ferrite bead to a cable. I had a project with LED lights fed by a magnetic transformer and when the lights were on there would be interference. I added ferrite beads to each of the 8 legs and the problem was fixed. Cost was an hour of my time and about $8.

I bought a house from a fellow who was taking apart $5 power strips and soldering on MOV's and then filling the insides with resin to disguise what had been done. He then sold them as special surge suppressors for $120. I see lots of people doing this in the audio industry with their magic wires and conditioners and filters that no reputable engineer would even think of doing.

larkone

You are assuming that a power cable is capable of picking up noise that is going to actually effect your hifi. Only if you are living directly under a TV or phone mast is that likely. Just because the manufacturer has added all of these snake oil pseudo-physics claims about their cable doesn't mean that they are actually required or can actually fix anything that would make a sonic difference. Where are the scientific papers that support these claims if they are that good? Save your money and spend it on more music.

xmb

Given the BP2400 isolates the mains between the input and output, and the enclosure will act as a ground plane, I would have thought there should be no need to use a screened mains cable on the input.

BlueWizard

There is nothing wrong with screened power cable. It seems pointless, but if the cable you are interested in happens to be screened, don't not buy it simply because of that fact.

However, the more critical aspect are the Connectors and the Wire itself. It doesn't make much sense to spend £100 on a 14ga Power Cable, when very likely your system came with a 14ga Power Cable.

Equally (I've seen this product) a 9ga Power Cable is just as pointless.

For reference, there are AWG wires relative to Cross Sectional Area -

16ga = 1.31mm²
14ga = 2.08mm²
12ga = 3.31mm²
10ga = 5.26mm²
_9ga = 6.63mm²

Common UK/EU Wire is -

1.5mm²
2.5mm²
4.0mm²

For those wondering about the power capabilities of various size wires, check out this thread -

General -
                                                                                                                                                                                                                                                                                                                                                                                                                                Speaker Wire in Prespective -How much is Enough?                                                                                                        What size speaker wire do you really need?  This question can be answered from several perspectives.  One is simply Resistance/Unit-Length. Practically applied you want the Resistive Losses to not exceed a certain percent of the Speaker Impedance. Charts for this can be found here -  Cable...                                                                                                                                                                                                                                                                                                                www.avforums.com                                                                               
10ga & 4mm² -
                                                                                                                                                                                                                                                                                                                                                                                                                                Speaker Wire in Prespective -How much is Enough?                                                                                                        What size speaker wire do you really need?  This question can be answered from several perspectives.  One is simply Resistance/Unit-Length. Practically applied you want the Resistive Losses to not exceed a certain percent of the Speaker Impedance. Charts for this can be found here -  Cable...                                                                                                                                                                                                                                                                                                                www.avforums.com                                                                               
13ga or 2.68mm² -
                                                                                                                                                                                                                                                                                                                                                                                                                                Speaker Wire in Prespective -How much is Enough?                                                                                                        Oddly the one Cable I did NOT calculate, which would have been the most helpful in the UK/EU is 13ga wire, which at 2.62mm², is closest to the common 2.5mm².  13ga (2.62mm²) Copper Cable -  438 Sustained Watts  2200 Working Peak (best guess) 9800 Max Peak Watts  Working Peak is unavailable at...                                                                                                                                                                                                                                                                                                                www.avforums.com                                                                               
14ga (2.08mm²) which is extremely common will sustain 279w all day long, with a working peak power capability of 1800w peak. The Maximum failure power for 14ga is 8192 Watts Peak.

To each his own.

Steve/bluewizard

Welwynnick

I would say the point is that the mains cable is physically closer to the equipment that you're trying to shield against.

That shielding can reduce the interference that is radiated by the power cable, and which may interfere with other equipment.  I think that's a very marginal consideration as mains power frequency is so low.  RF radiation is only effective at higher frequencies.

The other effect of shielding is to reduce the susceptibility of the cable to RF emissions generated by other equipment, especially things with video processing in them.

I suspect that the differences between cables are as much down to how they handle the unwanted signals as how they handle the wanted ones.

Apart from shielding, another thing a mains cable might be able to do is manage the noise and interference that is conducted along the mains cables themselves.  Mains isn't pure 50Hz AC sine waves, it's got lots of other muck as well.  By way of a simple domestic experiment, try connecting your BD player to a socket at the other end of the house via the longest extension lead you've got, and see if that makes a difference.  Better that than doing the keyboard warrior thing.

Nick

JohnnyNapalm

I use shielded mains cable behind my AV kit to help prevent/reduce the possibility of adding noise to my phono inputs which run between my AV Amp/Power Amps and subs as it is difficult to segregate them due to lack of space. Cheers.

Filipedine

In poder cables, the cable section might be even more importante than shielding, does not mean you Will ear a diference in the music, but rather means you can pass more current in the cables that have higher sections.

The power requierments of a MF M6i 500 is mutch different than the one from a Marantz PM6006 or a MF M3SI. Bigger cable section  allows you to deliver more current to the device without causing eléctrica issues to the gear or house eléctric system.

@JohnnyNapalm in your cable do yoU know if the shielding layer is conectei to the ground terminal?
If só is it only I. One end?

Thanks in advance

dannnielll

These arguments about the cabling on power systems needs to consider the supply. In Europe with a single phase supply of 220'v rms  or in UK closer to 230 V rms ,  the conductor thickness can be 1/4 that of a USA 120V cable for the same weakness.
Our standard 2.5 mm sq cable is capable of sustained 22 amps ,which in the context of European mains means 4.4kW !.
Speaker cable is a different discussion
Now Wellwennick makes the valid point that the mains cable is acting as an antenna and picking up all sorts of grot ..true. but any series inductance or parallel capacitor at the device will kill this. Even the interwinding capacitance of the transformer.will do the trick. The ferrite nodules often found on power cables for computer kit are not to protect the computer or printer ,.. actually the reverse. It is is kill transients being emitted by powerful switch mode supplies from propagating back into the switchboard. Except for Class D amplifiers ,with SMPSUs ,most audio equipment does not switch power... Some DVD players and  add on TV set top boxes use Smpsus,but not at high power.