Expensive IEC home cinema leads...just a kettle lead or what

[Stevethetiler]

Me again.

As im a realtively big home cinema fan....got the big tv , surround sound and all that...is there any proven benefit from having a shielded cable to connect my expensive home cinema set up?

Ive seen em claim to clean up "dirty mains supply" but would it really be of any benefit?

Or is this the right forum?

 

[mattylad]

Oh yes it will deffo benefit someone, especially the person that sells it to you

 

[Stevethetiler]

Kinda what i thought, but i thought id ask the electrics experts to see if there is any truth in shielding from RFI etc etc...........

 

[ericmark]

More to do with high power RF. I see Clwyd anywhere near Mold? Maybe a visit on a Wednesday Night to the Mold radio club in the rugby club building would help you make up your mind?

If your house in middle of no where is wired in ali-tube cable instead of twin and earth and all other causes have also been eliminated then maybe.

I know of one building where all the brick ties are earthed. And a rusty bolt caused huge problems with RFI.

It was used during early days of RADAR and when they found the dead seagulls and sent them for analysis seems they were landing ready cooked.

But when you enquire as to how much power was used you realise no real wonder.

At 400W transmitting power we are permitted to use without special licence it is rare to cause interference. And when we do it is more to do with cable length than shielding. If some one if transmitting on two meter band and you have two meters of cable between speakers and amp then likely you will suffer from RFI or EMC as most call it. Extend or shorten cable and no problem.

And all the shielding does is add another bit of wire able to receive signals.

Try with mobile phone near a mono compact radio and the interference is only found when the two are really close when it poles.

But use a stereo with remote speakers and does not matter what you do polling noise still gets through. I used coax on my speaker wires. I was a waist of time.

P.S. Why Clwyd? What is wrong with Flintshire, Wrexham etc.

 

[Taylortwocities]

A nice Tempest shielded cabinet would look really cool in the living room. And what a fine conversation piece..

 

[Stevethetiler]

Ericmark...whats the crack at the rugby club then? yeah im from wrexham and know mold.

Clwyd or flintshire....hard to know which one should be which..i always get confudddled

 

[Stevethetiler]

Ive seen some rather extravagant cables which claim to do all sorts (i dont mind spending 20 quid if it may give me a better picture/sound but some stupid folk pay hundreds for a 1m length of rhodium plated silver plated copper super conductor crap......

Im pretty sure its all just marketing but i did wonder if there was any REAL benefit from a shielded cable as opposed to the standard run of the mill cable you get with your tv etc.

Perhaps i should build a bunker in my garden with lead walls......surely no interference then....oh forgot...no bloody picture too !

 

[Stevethetiler]

Ive heard that some people use twin and earth as speaker cable instead of the expensive guff you can pay and arm and a leg for...my local hifi shop told me that is perfectly acceptable...i wouldnt have even thought about using it but when you think about it....i guess solid core is a better conductor than something like 79 strand?

 

[nozspark]

The thing with these shielded IEC leads is that you are trying to reduce the interference being emmited by the lead,,,,, but the rest of you electric cables are not shielded and are pumping out radio interference

As for using T&E I can't see a problem, although T&E is prone to damage if it's flexed

 

[Stevethetiler]

those pesky buggers who sell these leads say they reduce interference etc.

Not that its something i even wanna do, (given i love my music and home cinema) but some cretins spend thousands on cables....it must be a gimmick.

 

[Stevethetiler]

Noz, thats exactly what my hifi man said.....more or less....he said what difference is 1m of shielded cable gonna make compared to the cables you already have in your home.......it really is a no brainer i guess

 

[Stevethetiler]

Ive even seen MK tough plugs for sale with silver plated pins and fuse holder with silver plated fuse! i think the seller wanted £10 for em.

How much difference? - apparently none!

 

[ericmark]

Good radio club in Wrexham should have realised the is no Wrexham option for county.
We have only just had a lecture on transmission lines it is rather complex. but I will try to explain a little. Any cable will have an impedance and if the power feed to the cable matches the cable and the power from the cable also matches then maximum will be transmitted down the cable.
Because the frequency of sound varies the cable will not be correct for all sound but the gap between the two wires will alter the impedance of the cable and there will be a cable where the gap is best for most of the sound frequency sent down it. There are also signals superimposed on cables to improve there performance.
If you pop into NEWI on top floor of library corner closest to bypass roundabout there are loads of books on this.
Electrical Circuit Theory and Technology by John Bird a copy I have in my hand page 869 to 900 it explains the basics.
Since the speakers have an impedance of 4, 8, 16 or 32 ohms I would think you should be able to by the wire to match as 4, 8, 16 or 32 ohms impedance which is of course why using coax of 50 ohms impedance did not work for me.
I have worked with 300 ohm ribbon cable which makes me think the cores for speaker cable would need to be quite close together. The fact that there is an earth wire in twin and earth I would think would give it a relatively high impedance.
I did not do sound broadcast for my degree so never really got deep into cable selection.
But NEWI does teach that course and if you enter university from library go up the stairs the sound broadcast is in some rooms to left.
Having said all that do you really think your ears are of that quality?
Material of which the wires are made of is not so important as the material of insulation there is also a skin effect so stranded cables are different to solid core.
I know enough to realise how little I know but with digital format there is a limit to how good the reproduction can be and as a result I would think using matching networks and matched cable with correct impedance would have very little effect to what you hear.

 

[Stevethetiler]

That makes me feel like a complete novice !

I think my hifi man said to strip the earth and just use the remaining cores obviously one going to positive the other to negative.

Im quite happy with the exisitng setup....improvements to home cinema and hifi are only justifiable if you can see or hear the difference.

Im not sure that i would get any better than what i have at the moment.
For those in the know of home cinema i have a dedicated onkyo 606 cinema amp, q acoustics 5.1 speakers sony blu ray bdps350 and samsung le40a456 40inch tv.

Its all connected with good quality (not pricey) stuff.

I just kinda wondered what the craic is with all the electric guff they sell these days is in realtion to the improvement i would get for the outlay.

Your a top man eric, but at this time o nite, with a glass of wine, i may just have to come back and recap a little!

 

[breezer]

you all have not mentioned oxygen free cable