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Old 05-04-2016   #1
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Default Explain this: shielded AND twisted pair cables with RCA connectors

Lets start with Stinger's 9000 series rca cable for example:



Stinger claims that this particular construction if beneficial. I don't believe a word of it, but lets just go along with it for the moment.

I count twelve separate conductors inside that cable, plus the shield makes thirteen total. There are only two possible places to connect those wires at the end of the cable on the RCA connector. How exactly are those all connected together?

If you don't know anything about those specific cables I don't blame you, so instead think about a more general cable that has a twisted pair inside, and a braided or foil shield on the outside (this claim is so common!). That is a total of three conductors. How are they connected to the two conductors on the RCA connectors?

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Old 05-04-2016   #2
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

subd..

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Old 05-04-2016   #3
 
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Pretty sure the sheid is just for rf rejection, not actually carrying current. As for the 12 wires, your right. Marketing BS.

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Old 05-04-2016   #4
 
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

One could only assume they're all terminated at the pin (+) of the RCA connector. While the vast majority of marketing aimed at "HiFi" audio interconnects and speaker cables is pure snake oil nonsense, there is some merit to the multiple twisted pair archtecture. Personally, I don't buy it, or at least I don't fell the need to spend huge amounts of money for cables that provide so little, if any, functional benefits. If one was simply after a specific cosmetic and was willing and able to pay the price...hey, to each their own. With that said, good wire, good connectors and proper terminations can be purchased in bulk and made to suit one's exact needs, provide excellent performance and most likely cost considerably less.
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Old 05-04-2016   #5
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

every rca marketing gimmick into one! of course it's awesome.

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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Omg, the more I look at this the more BS it is. Two different metals for different frequencies, what, built in cross overs?

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Old 05-04-2016   #7
 
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

"That is a total of three conductors. How are they connected to the two conductors on the RCA connectors?"

The red wire goes to the Centre pin positive, the black (or white) wire goes to the lower spade part of the barrel negative ,the shield is soldered the spade part of the barrel below the black negative wire...the shield is only soldered at one end of the interconnect and this end is always plugged into a upstream component as a drain.


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Old 05-04-2016   #8
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Quote:
Originally Posted by mbradlawrence View Post
Pretty sure the sheid is just for rf rejection, not actually carrying current. As for the 12 wires, your right. Marketing BS.
If the shield is for RF rejection, it must be connected to ground at some point. So if the shield is connected to the ring of the RCA connector, what are those other twelve conductors doing? Are they all connected to the center pin, essentially making them all one conductor? Then why have so many separate twisted pairs and drain wires connected all together? What are the "drain wires" draining if they are connected to the signal conductor? It makes no sense!



Quote:
Originally Posted by emilime75 View Post
While the vast majority of marketing aimed at "HiFi" audio interconnects and speaker cables is pure snake oil nonsense, there is some merit to the multiple twisted pair archtecture.
Please help me understand the benefit of *multiple* twisted pair architecture for a single analog channel of audio.


Quote:
Originally Posted by Donanon View Post
"That is a total of three conductors. How are they connected to the two conductors on the RCA connectors?"

The red wire goes to the Centre pin positive, the black (or white) wire goes to the lower spade part of the barrel negative ,the shield is soldered the spade part of the barrel below the black negative wire...the shield is only soldered at one end of the interconnect and this end is always plugged into a downstream component as a drain.


D.
Are you saying the non-signal wire of the twisted pair is electrically connected to the same point as the shield is? What is the benefit of having the shield both fully enveloping the signal conductor, *and* also twisted around it inside the shield as well?

This is the crux of the problem. I don't understand it. Please explain it me.

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Old 05-04-2016   #9
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Quote:
Originally Posted by Donanon View Post
...the shield is only soldered at one end of the interconnect and this end is always plugged into a downstream component as a drain.
D.
Somewhat related to my original post. Grounding a shield on one end only is the same as a "ground lift" option on an interconnect cable. Rane does a great job explaining why this is not a solution to any problem, and may do more harm than good.

Quote:
In reality, the presence of a ground lift switch greatly reduces a unit's ability to be "properly" grounded and therefore immune to ground loop hums and buzzes. Ground lifts are simply another Band-Aid to try in case of grounding problems
Source: Sound System Interconnection

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Old 05-04-2016   #10
 
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

"Are you saying the non-signal wire of the twisted pair is electrically connected to the same point as the shield is?

Yes, but when I built interconnects for my install I attached the negative and shield separately but close together.

"What is the benefit of having the shield both fully enveloping the signal conductor, *and* also twisted around it inside the shield as well?"

The shield is used as an RF and noise drain back to the negative on the up steam component so the theory is that having the shield surrounding both wires and draining to the up stream negative helps to clean the signal.

I used Belden #83393 and built per Jon Risch:

Jon_Risch's Web Site


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Old 05-04-2016   #11
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

The page you linked doesn't give much information about why he chose that particular arrangement of materials, but the previous page gives a few seemingly contradictory hints. I highlighted some stuff in red.

Quote:
-Shields-
In coaxial type cables, the shield also carries the audio signal.
This may explain the superiority of the twisted pair construction,
as when it is shielded, the shield doesn't have to carry signal
current. It is much more difficult for a conductive cylinder sheath
to provide shielding action when carrying signal currents. If the
ground at either end is less than perfect, any hum or interference
that the shield is intended to intercept gets mixed with the audio
signal. This may occur at a very low level and be "inaudible" in
the sense that hum or RF are not heard outright, yet cause a subtle
blurring or graininess to be added to the signal.

With twisted pair or triaxial cable, the outer conductive sheath
known as the shield should only be hard grounded at one end
, typically
the low impedance signal source end. The other end can either be left
unconnected, or connected to ground via a 0.01 uF ceramic disc
capacitor to aid in RFI suppression. This can be one of the basis
for "one way" or "unidirectional" cables. This is known as a
telescoping or telescopic ground, due to the "nesting" of the inner
conductors within the shield from one end.

_________________________________________ Outer braid
__________________________________________________ _____ Inner braid

================================================== ============ Center wire
__________________________________________________ _____
_________________________________________
|
|
-------
---
-
Special Note:
Coaxial cables MUST have the shield connected at both ends, as it
supplies the ground return path for the signal. This is why the shield
braid can and will affect the audio quality.
He says that in coaxial cables, the shield also carries the signal. What? I thought the one and only job of the shield was to act as like faraday cage, protecting the central conductor from interference. If the shield is grounded, then how can it also carry the signal?

Then he says this particular cable should have the shield terminated at one end only. Then he says all coaxial cables must be grounded on both ends. Which one is it? Doesn't this particular cable act like a coaxial cable due to the conductors being shielded by a copper braid or foil?

Lastly, I couldn't find any mention of how to connect the twisted pair conductors to the RCA connector. I didn't see where you should connect one to the ring, and one to the center pin. Can you point that out for me?

I'm going to send him an email and ask a few questions related to above.

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Old 09-09-2016   #12
 
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

I posted this on Reddit recently when someone asked this and I thought it would help.

Quote:
Oh man, I love these questions!

So coming from Hooker Audio where we build cables using physics and not "magic" BS I think I can help with this ;-).

So here is the deal, there is only really three ways to deal with noise in an RCA.

Ground issues (called Ground Loops)
Protection from exterior "noise" or RF
EMI that occurs when you send current through a wire.

So the first one is an easy fix. RCAs are built where the prong in the middle and it is the where the audio signal transmits. The metal exterior ring on the RCA is a ground that slides around the plug on your amplifier. This ground connection must stay tight at all times. When you have a cheaper quality RCAs, over time the tension that this ring creates can weaken and then be loose. This weaker ground connection can cause noise also called a ground loop. A good RCA has some type of technology that will keep this retention over time. Our Hooker Audio RCAs, for example, have a patented twist end that actually tightens down after you install the RCA. I have seen dealers actually hang their amplifiers by the RCA ends(not recommended).

The second thing you have to deal with is RF from the outside. This is a real easy issue to fix with a mylar shield. This is a very common thing in a lot of wire manufacturers but the majority of them do it to make their RCAs look "cool" with a transparent jacket. The one thing you have to ask is if it is a mylar shield or something else just to make the cable pretty. They don't always do the same job, it depends on the materials they make it out of.

The third thing you want to take care of is Electro Magnetic Interference(EMI) and this is caused by electricity passing through a wire. You see this when you run a non-shielded RCA over the power wire because of the current running through it. After much testing many years ago, it was determined that you can reject EMI by using what they called a "Hum Buzz Shield". This prevented EMI from entering the cable and affecting the signal being transmitted. This was just a matter of taking two signal wires and twisting them 2.5 times every inch. When this is done it rejects noise and prevents the wire from creating its own EMI interference on itself. Any less and you can pass EMI from the outside into the audio cable. Any more than 2.5 times every inch and the audio cable actually creates its own EMI noise. This is why all of our wires are ran through the jacket this way. Be careful though because car audio manufacturers started twisting their wire more and more with the reasoning of that it "looked cool" but as I said before this is counter intuitive. I have actually seen some manufacturers do like 8-10 twists every inch and that just isn't good at all.

Now with this knowledge, you will be able to look at whatever brand wire you want and determine which is the best for your application just by seeing how it is made. Hopefully, that answers your questions
I am a little oversimplifying it a little in this post but that takes care of the majority of the issues

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Old 09-09-2016   #13
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Hey Chris,

Thank you for helping out. I have a few questions about what you have posted. I'm not attacking your words. I really want to understand what you are saying here.

A really good read on shielding, noises, ground loops and more can be found at Rane's website below, and this is what I'm basing most of my questions on:
Grounding and Shielding Audio Devices

As I understand it, ground loops are only a problem when multiple paths to ground are created when you connect one piece of equipment to another, and both are connected to an earth ground through the 3rd pin on an AC power cable, or the negative power terminal of a +12vdc product. If the shield (ring) of an RCA connector becomes loose over time and essentially disengages from the jack, then wouldn't that remove the multiple-ground-paths problem, and eliminate the possibility of a ground loop? I don't see how "lifting" one end of the cable's shield can make a ground loop worse (this procedure is used as a band-aid fix for ground loops too). I could see the single-ended shield acting as an antenna and introducing noise into the system as it picks up stray RF signals though.

Did I read that first big paragraph right, or were you saying something else?

I understand RF interference and how a mylar foil or a braided copper shield essentially creates a faraday cage that protects the center conductor. I also understand you can use star-quad geometry to cancel out the effects of stray magnetic field interference when using balanced/differential wiring.

But I'm not following your last paragraph about EMI. What it sounds like to me (using your example) is that running a bare wire next to another bare wire will cause voltages to be induced to one from the other due to EM coupling. This is how transformers work.

The solution you mention about twisting two signal wires together to combat this only works if the two wires are carrying signals in a balanced/differential configuration so that the noise can be rejected at the end because it is a common-mode noise.

I don't see how this twisted nature can help with unbalanced audio signal transmission. Please help?

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Old 09-17-2016   #14
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

It's like the idiot at BestBuy trying to sell you the $200 Monster HDMI cable. Marketing...we Americans are the worst and most gullible. We can be made to believe anything! Just assume a business man, salesman is automatically trying to screw you over. Makes it much easier.

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Old 09-18-2016   #15
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Complete nonsense. The ability of manufacturers to separate consumers from their money should never be underestimated.
I wish some third-party sound lab would a/b test all these boutique RCA cables and put an end to this lunacy once and for all.

Absolutely State Of The Art!
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Old 09-19-2016   #16
 
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Hey CarAudioChris,

Thanks for posting that very enlightening info. I stand corrected and more educated in terms of the audio world, I am going to re and re the cables in my car to match the description in your post to determine what if any improvement can be heard. Even if there is no improvement I'll sleep easier knowing that at least the wiring is not detrimental to the install.


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Old 09-21-2016   #17
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Quote:
Originally Posted by Jazzi View Post
Hey Chris,

Thank you for helping out. I have a few questions about what you have posted. I'm not attacking your words. I really want to understand what you are saying here.

A really good read on shielding, noises, ground loops and more can be found at Rane's website below, and this is what I'm basing most of my questions on:
Grounding and Shielding Audio Devices

As I understand it, ground loops are only a problem when multiple paths to ground are created when you connect one piece of equipment to another, and both are connected to an earth ground through the 3rd pin on an AC power cable, or the negative power terminal of a +12vdc product. If the shield (ring) of an RCA connector becomes loose over time and essentially disengages from the jack, then wouldn't that remove the multiple-ground-paths problem, and eliminate the possibility of a ground loop? I don't see how "lifting" one end of the cable's shield can make a ground loop worse (this procedure is used as a band-aid fix for ground loops too). I could see the single-ended shield acting as an antenna and introducing noise into the system as it picks up stray RF signals though.

Did I read that first big paragraph right, or were you saying something else?

I understand RF interference and how a mylar foil or a braided copper shield essentially creates a faraday cage that protects the center conductor. I also understand you can use star-quad geometry to cancel out the effects of stray magnetic field interference when using balanced/differential wiring.

But I'm not following your last paragraph about EMI. What it sounds like to me (using your example) is that running a bare wire next to another bare wire will cause voltages to be induced to one from the other due to EM coupling. This is how transformers work.

The solution you mention about twisting two signal wires together to combat this only works if the two wires are carrying signals in a balanced/differential configuration so that the noise can be rejected at the end because it is a common-mode noise.

I don't see how this twisted nature can help with unbalanced audio signal transmission. Please help?
Twisting does not help with unbalanced signals - you are correct.

A ground loop is created when there is more than one path to ground with different but similar impedances. A completely disconnected shield/ground wouldn't cause this, but a loose connection would.

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Originally Posted by Orion525iT View Post
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Old 09-22-2016   #18
 
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Quote:
Originally Posted by lizardking View Post
It's like the idiot at BestBuy trying to sell you the $200 Monster HDMI cable.
People buy them every single day. So who's the idiot? $$$$
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

I think where the science is behind this (not saying it works or not) is that capacitance (magical force that causes the voltage to lead/lag the current) is created by having conductors close together over a length of said conductor. While inductance (another magical force that causes voltage to lead/lag the current, but exactly opposite of capacitance). Inductance is created when a conductor is rolled into a coil.
Pretty sure that the basis is that the capacitance that might have been created could be cancelled by inductance that the twisting may create.
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Old 10-15-2016   #20
 
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Interesting, in my industry EMI sensitive wires that are shielded are terminated to ground at one end only. Grounding at both ends usually creates unwanted EMI from the shield itself. If a cable assembly is ran between two equipment racks and you were to ground at both ends to the chassis or equipment rack frame, there may be a potential difference between the two grounding points. This I assume is because in a car, the chassis is the ground and the return for the B+. In my industry B+ & B- are independent of the chassis/earth ground. There is a lot of metal between the different equipment racks and impedance to chassis ground can vary significantly creating the difference in potential.

IMHO, ground loops are the result of damaged or poor quality components and should be addressed accordingly. RF interference should be rare in a car except where keyless transmitters are. I have heard of folks getting Rf interference from keyless xnsmitters and re-routing or local shielding will work. It would be interesting to know how much current would actually cause EMI? When I think about how much current is running through most sub woofer wires that are not shielded and are in fact running side by side to each other then it must take more than what most audio systems are capable of generating.
Sounds like these fancy cables are band aid solutions to the root cause. There are some really interesting articles on the difference between CAT II, CAT III and so forth but they are for networks that have very low voltages and suseptible to interference easily.

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Old 10-16-2016   #21
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

I was getting ground noise one time and after answering a series of questions Glenn told me to get a leftover rca cable out of the way that was tucked behind the headunit. I was getting EMI iirc. Being at wits end I tried it and by golly he was right.

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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

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I was getting ground noise one time and after answering a series of questions Glenn told me to get a leftover rca cable out of the way that was tucked behind the headunit. I was getting EMI iirc. Being at wits end I tried it and by golly he was right.
That is an odd one! I wonder if one end was touching the chassis? or the housing of an electronic component. I was having an issue with noise once and after swapping amps and RCA's I decided to shield the RCA's and still had the noise. I ended up swapping an old H/U unit I had laying around and the noise went away. I figured maybe that I was crazy and put the original H/U back in and the noise came back. The Original H/U worked fine for about a year and a half and then all of the sudden came the noise.

I did purchase an extended warranty on the H/U so I called Alpine and after a few rounds with fairly average tech support, they agreed to replace the unit. Never had another problem. I had some people advise me to daisy chain all of the outer RCA plugs together and that just seemed like a band aid. The funny thing about band aids is that they work very well on people, but machines and parts don't heal themselves.

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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

Sorry everyone, don't know what happened to my CarAudioChris account but I will answer these questions here shortly
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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

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That is an odd one! I wonder if one end was touching the chassis? or the housing of an electronic component. I was having an issue with noise once and after swapping amps and RCA's I decided to shield the RCA's and still had the noise. I ended up swapping an old H/U unit I had laying around and the noise went away. I figured maybe that I was crazy and put the original H/U back in and the noise came back. The Original H/U worked fine for about a year and a half and then all of the sudden came the noise.

I did purchase an extended warranty on the H/U so I called Alpine and after a few rounds with fairly average tech support, they agreed to replace the unit. Never had another problem. I had some people advise me to daisy chain all of the outer RCA plugs together and that just seemed like a band aid. The funny thing about band aids is that they work very well on people, but machines and parts don't heal themselves.
The extra cable was wrapped around a wiring bundle in the dash. I tried all my trouble shooting tricks and couldn't figure it out. Just a whole lot of strange going on that didn't make sense. Like when you leave a cable wire unplugged you can use a device to detect it from the road. That poor truck went through a lot in nearly 6 years. I caved and traded in the pig for something a lot more practical. The new rig will have ZERO rca cables over 3' long.

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Default Re: Explain this: shielded AND twisted pair cables with RCA connectors

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