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Different cable structures for RCA interconnects

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So my message that coax is not the simple or normal design for RCA cables does obviously not have any reason to be challenged.

Yes it does ... because you are wrong. microphone cable, commonly used in rca patch cords is a type of coaxial cable.

The problem here is that YOU DON'T KNOW WHAT COAXIAL CABLE IS.
 

Audiofire

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Most RCA cords are made with microphone cable ... which is a type of coaxial cable.
Demonstrably wrong, microphone cables are balanced twisted pairs in line with the design of twinaxial cables (my understanding of what generic/normal RCA cable is has now been reassessed to be coax though).

Edit: Douglas Blake is now "Deleted member 46664".
 
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Audiofire

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The only thing necessary to deem cable as "coax" or "coaxial" is that it has one central conductor surrounded by a shield.

Some of the more common types of coax are ... Microphone cable, patch cords, instrument cables, television cable, radio transmitter cable... and on and on.
The trick is that you have to define an arbitrary center in order to call two separate wires coaxial, since you are talking about rotation around an axis. Or I just took my thought experiment way too far, and we all agree that the middle of the two wires is the center that defines the coaxial cable.

So is it just me that doesn't know what coax is, or does it actually need to be a central conductor surrounded by the neutral conductor (that is to say not two insulated wires per channel)?
 

mansr

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So is it just me that doesn't know what coax is, or does it actually need to be a central conductor surrounded by the neutral conductor (that is to say not two insulated wires per channel)?
Coax is short for coaxial, meaning the two conductors share a common axis. Two wires that are merely adjacent do not have this property. Does this answer your question?
 

MarcosCh

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The trick is that you have to define an arbitrary center in order to call two separate wires coaxial, since you are talking about rotation around an axis. Or I just took my thought experiment way too far, and we all agree that the middle of the two wires is the center that defines the coaxial cable.
Unless it is circular (what doesn't make much sense if you are connecting two devices) a normal cable as we know it only has one rotation axis.
 

Audiofire

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Unless it is circular (what doesn't make much sense if you are connecting two devices) a normal cable as we know it only has one rotation axis.
Coax is short for coaxial, meaning the two conductors share a common axis. Two wires that are merely adjacent do not have this property. Does this answer your question?
Thanks, it does. Are the two wires coax if a shield and PVC jacket are wrapped around them as suggested (above)?
 
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radix

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Coax and twinax, etc., are pretty simple, it's just the nomenclature that might trip someone up. Coax has two conductions: the center and the shield. But they are usually described as a single conductor plus drain (shield). Don't be fooled -- the drain is a conductor! And it is insulated. The only difference is the conductor is spread out on the surface of a cylinder. This can be done by using a foil, or a foil plus solid wire, or various forms of braids. Drains are also rated by how complete of coverage they provide.

Twinax is two signal conductors in the center of the drain (shield) conductor. So, there are 3 conductors, but it's usually called two conductor plus drain, as you only get two signal conductors.

For stereo, you need two coax. A typical RCA cable is two coax conductors with the outer rubber melded together for convenience. It is not twinax. As others have mentioned, RCA is the name of the connector not the cable, but consumers usually don't think of it like that. They know "RCA" for analog stereo interconnects and "coax" for spidf digital interconnect.

Pretty much all low voltage, high impedance systems (like stereo line level) wants to use coax for the shielding. That's because a fairly low power noise coupling can show up on the output. Speakers not so much, as they are driven by current, not voltage, and coupled noise will generally be low power. Of course, really long speaker wires can pick up enough noise to be audible, thus step up/down transformers....
 
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