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Please help me understand this cable.

KiranPS

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#1
I always assumed that you need shielding on signal cables, especially the ones that
connect the source like CD Player or a Turntable and a Preamp. The shielding forms
a sort of electrical barrier around the conductor that is actually carrying the
signal against Electromagnetic Interference EMF/EMI and Noise like Transformer Hums, Tube light choke spikes etc.

If this the case wont the following braided cable offer absolutely no protection against EMF/EMI and would actually be worse than even the cheapest shielded cable ? So why are these fancy
Cable companies charging so much more for what is actually an absolutely inferior product ? It looks like the twisted Red+Black electrical wire used connected to RCA plugs.

Do they assume we don't even know basic electronic knowledge about shielding a signal cable
or
Are each of those braided wires are actually shielded cables and not individual wires ?
 
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jls001

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#2
I believe to carry line level signals (from CDP, phono preamp out, tuner, etc), the twisting is sufficient to nullify the interferences. Of course this doesn't look suitable to carry very low level signal from a turntable to the phono preamp.

Most of these braids are Litz braids. Though some like Anticables use a spiral.

Bottomline: your rant may not be totally justified:)
 

KiranPS

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#3
So why doesn't everyone use twisted electrical lamp cable for Audio Signal cables :D ? I bet they are a lot cheaper and easier to manufacture than shielded cables ? :)
 

KiranPS

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#5
The above one is Kimber PBJ 2-RCA


The following one is Kimber Kable - GQ-Mini CU
This looks exactly like twisted electrical lamp wire.
 

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Thad E Ginathom

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#6
I think some of the Kimber stuff is like this. Even though I smirk at silly-price wires, I have some respect for Kimber.

Pros and cons of the construction? No idea. Let's here from one of our technical people on that
 

cmsajith

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#7
Braiding is a way of shielding.

So why doesn't everyone use twisted electrical lamp cable for Audio Signal cables
You can. if you are happy with the sound go ahead with it. All cables are not same, shielding is not the end of an IC. That makes some expensive cables different.
 
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corElement

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#8
Don't let the looks of a wire fool you. They may look like ordinary cables but they do research on it before putting a price on it.

The effects of shielding are more important as the length of the cable increases. The longer they are, the more shielding they need. However there is theory that unnecessary shielding "damages" the signal.

Also, many different layers of cheap shielding are worse than 1 layer of a well researched shielding material.

Shielding is as necessary as it is in any given situation. One may get away without, or may not. Depends on the gear and ambient EMI/RFI.

I use a 0.5m long minimally shielded litz cable myself.

 
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KiranPS

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#9
Can you pls point me to the original thread. I hope, I can get some technical reasons behind this.

Long back, When I used to build DIY Tape decks , the cable I used to connect the Tape Head to the preamp board (which was probably 2-3 inches since longer ones loose the signal) and the cable for connecting the Preamp board to the power amp used to play a huge role in the amount of hum and other noises I used to get.
Grounding the Shield Wire to the head Body and the Amp Body was also very important to prevent noise.

You can also open up any preamp/amp and see that all the signal cables like the ones going to the Volume/Tone Controls use shielded cables.
 
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Thtpro

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#10
Looks like the Kimber PBJ 2-RCA cable has 3 conductors- red, blue and black. I can explain the reason for the twisted pair -- not necessarily 3 conductors

Most audio equipment input is looking for the voltage difference between the two conductors of wires (In this case the center pin and the outer ring of the RCA connector).

In a audio cable, with two closely-spaced conductors twisted together, audio is balanced equally on these wires, flowing in a positive direction on one wire, while in a negative direction on the other. Equipment looks at the voltage difference between those wires, and ignores everything else.

Any interference radiated into the cable is picked up equally by both. But remember: the equipment is looking for a voltage difference between those wires. Noise is the same on both wires, so the equipment can't hear it.

So twisting a pair of wire-- can eliminate the interference

I'll let other experts explain the reason for the third wire--
 
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KiranPS

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#12
Hi Thtpro,

What you are explaining is the Differential signals that are generated for noise immunity in applications like RS485 , where there are differential signals are generated by splitting the signal into + and - Potentials and sending them over a twisted pair and combining them back. When EMI happens they will affect both the wires the same way either in + or in - so this can be ignored.

Please correct if I am wrong, I don't think audio signals in RCA cables are differential signals. Its one ground and one signal.
 

Thad E Ginathom

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#13
It sounds to my relatively ignorant mind, also like the concept of balanced connections, which these cables are, of course, not.

Has anybody with a three-conductor cable removed the covers to the connectors to see if the third "conductor" actually is? A third strand could be there just to enable the cable to be plaited rather than twisted. It could be there to give contribute to physical strength, cosmetic appearance, or even some technical reason to do with the pitch (crossing angle) of the signal carrying conductors.

Just guessing :)
 

tanmayj

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#15
Could you mail the cable company technical support and ask the answer to this? If they're putting a big price behind it, I'm sure they'll be able to technically justify it.
 

Thtpro

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#17
How does a drain wire work? Does it make the wire a directional wire-- meaning the drain wire has to be grounded at the source or at the receiving end? or does it not make a difference?
 

Thad E Ginathom

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#19
Drain Wire

Reminds me of those innocent days when there were computer pranks, rather than viruses. The machine, on boot, displayed a message: "WATER FOUND IN SYSTEM: DRAINING," It then played a gurgling sound on the PC speaker and proceeded to boot normally.

:eek: OK, obviously this is a technical term which I don't understand the meaning of...
 

KiranPS

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#20
I guess we need faith ... Er... Blind faith in cable companies to give us better cables when they charge a lot.
 
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