Advice required on DIY mains IEC leads for home cinema kit

Stevethetiler · 19 Apr 2009

Hi All.

After some expert advice regarding changing the standard IEC type leads that were supplied with my home cinema components (TV / Blu ray / Sky+ box / AV amp / Powered Subwoofer)

i've seen various cables available off the shelf but are very costly.

Im looking into making some myself using IEC style connectors (fig 8 etc), a quality 3 pin plug and some better shielded cable between the two.

The existing cables are approx 1.5mm typical bog standard stuff.

haven't changed any fuses in any of the kit and fused ratings are as follows:

40" LCD = 10amp - power consumption in the book is 200w
Blu ray player = 13a - power consumption in the book is 26w (odd that its got a 13a fuse?)
Sky= Box = 3a - power consumption rated as 60w max in the book
Powered Sub = 3a - power consumption rated as 100w in the book.

The cable im looking at (which has been recommended for use in this application for its shielding) is -

http://www.lapplimited.com/14/en/products/oelflex_R/oelflexR_classic_110_cy/index.html

The version i have read to use is the 2.5mm 3 core version (this one will have numbered black cores as opposed to coloured).

This is supposedly, as i have read, suitable.

Questions being as the cable is bigger, do i need to alter fuses or stick with the sizes supplied? -

Is the cable suitable? - have been told it is but would like to make sure.

Any advice gratefully received.

Thanks in advance.
Steve.

rebuke · 19 Apr 2009

Shielded cable on the power lead will make no difference if you're trying to improve audio/video quality. The only reason I can see for making your own is if the existing ones aren't the right lengths etc...

If you insist on using this cable (which as I say will make no difference!), then you only need 1.5mm, since that will easily take more than 13A, which is the max that could be put through it. In terms of fuses, the existing ones would be OK, but to be honest I'd put 3A in each, none of the appliances should draw more than that, so there's no reason to put larger ones in.

I'm not sure on the regs on using cable without colour coding in an appliance flex, you may have to put coloured sleeving/tape over the cores when you terminate it, or it might just be not allowed - hopefully someone else might know that...

Stevethetiler · 19 Apr 2009

Thanks for that mate,

I guess its the old argument of "do better cables give better results".

Lots of people say they do, lots say they dont.

The idea of the shielding (at least in my brain

) is to reduce or eliminate as much RF or EMI as possible. I appreciate the fact that there is 100's of miles of crappy cable from my local substation and yeah, the fact could be argued that 1.5m of better cable wont make any difference.

I guess the thought behind using 2.5mm as opposed to 1.5mm has something to do with larger surface area for the current to flow, im not exactly sure of the science behind it all

I have heard benefits using better quality audio leads on my hifi setup, and using some better quality HDMI leads too.....i guess all im trying to do is ensure that what i have got is working to its optimum performance without spending out "ridiculous" sums of money in the process.

For a modest outlay of say, £15 per lead, its worth a stab anyhow.

ban-all-sheds · 19 Apr 2009

Stevethetiler said:
After some expert advice regarding changing the standard IEC type leads that were supplied with my home cinema components (TV / Blu ray / Sky+ box / AV amp / Powered Subwoofer)

What experts were these? What theories, totally unsupportable by any science known to man, did they put forward to justify changing the cables?

i've seen various cables available off the shelf but are very costly.

That's because they contain snake oil, a very expensive substance.

Im looking into making some myself using IEC style connectors (fig 8 etc), a quality 3 pin plug and some better shielded cable between the two.

Why do you think they need shielding? Shielding against what?

Blu ray player = 13a - power consumption in the book is 26w (odd that its got a 13a fuse?)

The fuse is to protect the cable.

The cable im looking at (which has been recommended for use in this application for its shielding) is -

How do you terminate the shielding at the plug(s) to earth it?

The version i have read to use is the 2.5mm 3 core version

Pointlessly oversized - nothing you have needs anything bigger than 0.5mm², although if higher rated fuses are needed because of start-up surges then you might need 1.0 or 1.5mm².

(this one will have numbered black cores as opposed to coloured).

An unnecessary complication - electrons can't tell the difference between coloured insulation or numbered black, so it won't make any difference to how the cable performs.

This is supposedly, as i have read, suitable.

Read where?

Questions being as the cable is bigger, do i need to alter fuses or stick with the sizes supplied?

Hopefully you won't be using a cable that size. If you do go ahead with it, for no sound reason whatsoever, make sure that any plugs you buy can accommodate conductors that size. A larger cable can support a larger fuse, but it doesn't have to, so you should stick with what the equipment maker recommends.

Is the cable suitable? - have been told it is but would like to make sure.

I would say it's not.

Zambezi · 19 Apr 2009

The old better cable = better audio/video debate, will never be resolved. Audiophiles swear blindly that bigger is better and you can tell the difference, in some instances I agree but mostly it is a con to sell very expensive cables and connectors (with a few drops of snake oil in the mix

)
If you want all the bits or ready made cables this guy seems to have a pretty good selection
http://stores.shop.ebay.co.uk/Audio-Friendly-Shop__W0QQ_armrsZ1

flameport · 19 Apr 2009

The main problem here is that CY cable cannot be correctly fitted into plugs and sockets directly - it should be terminated in the correct gland.

If you still want to use CY, it can be obtained with coloured cores:
http://www.csedistributors.com/acatalog/CY-Cable-3-Core.html#a750

The surface area of each wire is of no relevance in this application. While AC does tend to flow at the surface of conductors, at mains frequency (50Hz), you would need conductors of at least 200mm before it had any real effect.
Even then, just using a larger size is useless - you would need to use several smaller insulated wires in parallel, or shaped conductors such as flat bars instead.

Stevethetiler · 19 Apr 2009

No need for sarcasm Ban with the "snake oil" comment!

I have seen and read articles on t'interweb (yes i agree, some can be a load of utter garbage aimed at selling over spec'd supper plated this that and the other.

The reason why i stated numbered black cores is that i knew if i didnt, i would get slated by the sparkies for using a cable that isnt brown blue and earth for the intended application (however , i can do dot to dot and join cables up myself for my own use - they arent a permanent part of the wiring - they are for MY sole use and no one elses)

Zambezie, i have visited that ebay shop, sells some good bits and bobs.

Zambezi · 19 Apr 2009

You can spend well over £300 on a 1m power cable which is bonkers!!! I guess there is a mug born every day! The silly thing is that you can fit 2.5mm square cable (if you can terminate it in a 13A plug top) but it runs through a fuse wire that is 0.something of a millimetre

BTW other suppliers of audio kit are available and I have affiliation to that eBay shop.

Stevethetiler · 19 Apr 2009

Regarding earthing the braid, its my understanding that the braid gets "combed" out at the plug end, twisted to form a spur, insulated with sheathing and then connected to the earth pin of the plug (wall end)

The other end is left unattatched (properly insulated so no stray wires using som heat shrink.

This, by my understanding (and dont shoot me, im just the messenger!) forms an earth loop.

Point taken regarding core size and i have looked at some alternatives using several smaller cores which may be a better idea.

Ive heard that most appliances emit RF / EMI to a degree.....my logic was only to limit the amount that MAY be present as i have cordless phones, wireless router for laptop, wireless AV signal senders, mobile phones etc etc.

The whole point of the exercise was purely to limit the amount of any such interference affecting the possible performance of my AV set-up.

ban-all-sheds · 19 Apr 2009

Stevethetiler said:
Thanks for that mate,

I guess its the old argument of "do better cables give better results".

There's no such thing as a better power cord - at least not better as in performing better

Lots of people say they do, lots say they dont.

Those who do have a financial interest at stake.

They either make/sell snake-oil, or they produce magazines which review snake-oil or they have spent money on snake-oil and don't dare admit it was a complete waste.

The idea of the shielding (at least in my brain ) is to reduce or eliminate as much RF or EMI as possible. I appreciate the fact that there is 100's of miles of crappy cable from my local substation and yeah, the fact could be argued that 1.5m of better cable wont make any difference.

It can be argued, it is so argued, and it won't make any difference.

I guess the thought behind using 2.5mm as opposed to 1.5mm has something to do with larger surface area for the current to flow, im not exactly sure of the science behind it all

That's because there is none. The skin effect does not manifest itself at 50Hz.

I have heard benefits using better quality audio leads on my hifi setup,

For analogue signals of a few mV and frequencies in the 10's of kHz it's feasible for cables to affect the signal.

But power cables carrying 50Hz 230V? No way.

and using some better quality HDMI leads too.....

HDMI is digital - "better" cables can't do anything.

Did you hear improvements in the course of a proper double-blind trial? If not, anything you think you heard is suspect, I'm afraid.

i guess all im trying to do is ensure that what i have got is working to its optimum performance without spending out "ridiculous" sums of money in the process.

For a modest outlay of say, £15 per lead, its worth a stab anyhow.

Buy £60 of Premium Bonds instead - that might make a big improvement.

Stevethetiler · 19 Apr 2009

Ban.

Ill give you an example.

I used to have a normal bog standard scart lead connecting sky+ to the TV - it did what it said on the tin and carrried audio and video to the tv.

I replaced it with a QED scart cable which is dedicated RGB only meaning no sound, just picture.
Yes, you will probably dsescribe gold plated scart leads etc as "snake oil" and you are entitled to your opinion.

BUT - the more expensive cable provided a much clearer/ sharper picture with move vivid colours.

The thing with HDMI, what you say is true to a degree.

Yes it is digital so carries information in form of "0" and "1".
You may argue that the signal either gets there or it doesnt so no matter what lead you use, its will either work or it wont.

Stop to think for a minute though....because all those 0's and 1's need to be broken down, then transmitted and finally converted into picture and sound.

Yes, digital is supposedly lossless transfer of data but can you be certain that some of the data is not lost or mis interpreted between output and input?

flameport · 19 Apr 2009

Analogue signals work on varying voltages, which correspond to the different aspects of the picture (red green and blue in the case of your RGB cable).
Any interference or degredation of the signal will affect those individual elements.

Digital is just data - it either gets to the destination or it does not.
There is no way for colours, luminance, sharpness or anything else to be affected, since these are not individual elements within the cable.
If parts of the signal are lost or corrupted, the picture is destroyed.

Stevethetiler · 19 Apr 2009

Surely, with all those 0's and 1's flying about at the speed of light (maybe a bit slower

there would be a few bits of data that get corrupted or lost in transmission.

The picture/sound shown or heard would reflect that ... it wouldnt just disappear altogether surely?

I suppose the argument FOR a quality HDMI lead is that it they reduce the amount of data lost or corrupted.

The argument AGAINST would be digital either gets there or it doesnt.

Lots of audiophiles spend vast amounts of money im sure. Their argument would be that you dont buy a rolls royce and drive it using remoulds do you?

Im nowhere in the league of spending thousands but as it is a HOBBY, i do like to make relevant tweaks here and there if they may make an improvement. Hence this thread.

Stevethetiler · 19 Apr 2009

Surely such things as colour , luminance and eveything else that is transmitted digitally, has to be converted into binary and the re- interpreted at the other end..

flameport · 19 Apr 2009

Stevethetiler said:
The picture/sound shown or heard would reflect that ... it wouldnt just disappear altogether surely?

Yes, that is exactly what happens.
All or nothing.

http://en.wikipedia.org/wiki/Cliff_effect

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Advice required on DIY mains IEC leads for home cinema kit

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