Different cable structures for RCA interconnects

[JensenW]

Hi everyone! I hope you're all well.

I'm going to get a pair of RCA interconnects for my CD player to Integrated Amp, and I stumbled upon a few major types of cable structures:

1. Coaxial with shield and single central conductor (eg. Oyaide FTVS-510, just an example, not saying I'm eyeing this particular cable)
2. Coaxial with shield and a pair of central conductors (eg. Oyaide FTVS-910)
3. Twisted pair of conductors with a shield (eg. Grimm TPR)
4. Pair of conductors each in its PVC sheath running parallel

For (1), if I terminate the central conductor (+) to the central RCA pin and the shield (-) to the sleeve, does it mean that the shield is simply just a negative wire and not performing as a shield, and is thus no different from (4)?

If I use (2) or (3), I would terminate one conductor to the RCA tip and the other conductor the the sleeve, and I still have a shield which I can connect in a floating manner to the source end.

I have read that 2/ 3 are for making balanced cables and 1/ 4 are for single-ended, but I couldn't find any answers as to how the shield of the single-conductor coaxial cable (1) could still work when used as the negative wire with both ends terminated to the RCA plug sleeve.

Thanks!

 

[DVDdoug]

You need two connections on each end and a grounded shield. That's it and anything else is redundant. With two connections you don't need more than 2 wires. With line-level signals you might actually get-away without a shield because the output is low-impedance and that minimizes noise-pick-up. But I wouldn't recommend it.

There are cases where removing the ground at one end fixes a ground loop. The shield should still be grounded at one end.

A proper balanced connection is 3 wires and 3 connections at each end. Two opposite polarity signal wires plus a ground, so an RCA connection can't be balanced.

It could be done with two RCA connections but I've never seen that. Well... I have seen it accidently with the "wrong" adapters and then the left & right signals get subtracted at the differential input and you get a center-channel "vocal remover".

 

[Lambda]

If you have unbalanced transmitter and receiver true Coaxial is the best option.

RCA cable Magnetic interference measurement and comparison

Cables are cables and there is no difference?! I designed a test to see if they perform significantly different in therms of "magnetic shielding" or Leakage inductance. This test dose not test for ground loop currents but interference from close by magnetic in homogeneous magnetic files. The...

www.audiosciencereview.com

You can "improve" on coaxial by adding ferrite cores and reduce the effect of high frequency interference.

 

[JensenW]

Thanks. I guess I'll get a coaxial cable.

I'm still a little confused, for an RCA to RCA line level interconnect, is using "two conductor + shield coaxial" better than a "one conductor + shield coaxial cable, so that I can terminate the two central wires to the RCA pin and sleeve, while making the shield a true floating shield (connected to one side only), instead of using the shield as a "wire" connecting both ends of the RCA plug sleeve, which the shield apparently is not working as a shield but as a conductor only?

 

[DSJR]

So much nonsense written on cables and their supposed sonic characters and the people more deeply into this really genuinely believe it all. Only a proper blind comparison will help break the condidioning but they find excuses all the time for not telling any difference when the identity of the cable isn't known.

As regards RCA cables from a CD player to amp (so red-book 22.2khz or so frequency limit), you know, a set of Amazon basics RCA 1m cables would be fine (as long as you didn't know its identity or price, as thi smakes them appear worse for psychological reasons). From known trusted pro cable vendors, I'd stick with a proper coax type with not silly RCA's at each end (Mogami is a popular one) and at this point, avoid the extra cost and complexity of two-core-with-shield, let alone star-quad for a mere RCA connection (do as I say here, not as I do - cough).

Here ya go for US posters -

https://www.amazon.com/Foot-High-Definition-Interconnect-Amphenol-Connectors/dp/B01GNXO67K/ref=sr_1_2?crid=158QTIFEXIUKY&keywords=worlds+best+cables+rca&qid=1641231210&sprefix=worlds+best+cables+rca%2Caps%2C840&sr=8-2

Not as cheap and cheerful as the Amazon Basics cable with so surprised me how 'good' it is, but a cable with decent materials from trusted suppliers and available in different lengths. The cost isn't silly in my opinion, bearing in mind it's been almost certainly hand, rather than machine made...

Seriously at this point, I'd honestly forget fancy cables for RCA's as they're a royal pain to make up and I don't think they make much of any difference in 1m or so lengths having tried different types over the decades. I've used mic cables wired with hot for + and return and screen connected together at source (usually), but in a short length it's unnecessary faff I think.

 

[JensenW]

So much nonsense written on cables and their supposed sonic characters and the people more deeply into this really genuinely believe it all. Only a proper blind comparison will help break the condidioning but they find excuses all the time for not telling any difference when the identity of the cable isn't known.

As regards RCA cables from a CD player to amp (so red-book 22.2khz or so frequency limit), you know, a set of Amazon basics RCA 1m cables would be fine (as long as you didn't know its identity or price, as thi smakes them appear worse for psychological reasons). From known trusted pro cable vendors, I'd stick with a proper coax type with not silly RCA's at each end (Mogami is a popular one) and at this point, avoid the extra cost and complexity of two-core-with-shield, let alone star-quad for a mere RCA connection (do as I say here, not as I do - cough).

Here ya go for US posters -

https://www.amazon.com/Foot-High-Definition-Interconnect-Amphenol-Connectors/dp/B01GNXO67K/ref=sr_1_2?crid=158QTIFEXIUKY&keywords=worlds+best+cables+rca&qid=1641231210&sprefix=worlds+best+cables+rca%2Caps%2C840&sr=8-2

Not as cheap and cheerful as the Amazon Basics cable with so surprised me how 'good' it is, but a cable with decent materials from trusted suppliers and available in different lengths. The cost isn't silly in my opinion, bearing in mind it's been almost certainly hand, rather than machine made...

Seriously at this point, I'd honestly forget fancy cables for RCA's as they're a royal pain to make up and I don't think they make much of any difference in 1m or so lengths having tried different types over the decades. If you use RCA to remote power amps several metres away, then a mic cable of some sort (I really like Mogami 2549 currently) would be worth a look.

So I get it that for a short length (eg. 1.5 meters/ 5 feet), a single conductor coaxial should be fine. For long distances RCA, the shield will be more useful, thus something like the Mogami 2549 which allows a two conductor connection and a working, floating shield will be useful.

In case of longer runs, would the Mogami 2549 type of shielded two-conductor structure or the Oyaide FTVS 910 (twisted pair of central conductors in a shielded coaxial cable) make any theoretical difference in their shielding ability, considering that they both have 100% shield coverage?

Out of curiousity, I browsed the Mogami site and found that their 2803 has the "highest resolution" of all their coaxial cables (and is really expensive). My impression is that Moagmi is a professional and no-nonsense company. I think the 2964 is in every way as durable as the 2803. Is there something that makes the 2803 a better performer than the 2964 (even only on paper, i.e. not audible)?

 

[Lambda]

a single conductor coaxial should be fine.

It is always the preferred option. compared to something with less symmetry (like twisted pair.)
Only thing better then Coax is coax with extra electrostatic screen also clade Triaxial.

In case of longer runs, would the Mogami 2549 type of shielded two-conductor structure or the Oyaide FTVS 910 (twisted pair of central conductors in a shielded coaxial cable) make any theoretical difference in their shielding ability,

No for unbalanced twisted pair is significantly worse then coax in therms of electro magnetic noise rejection

impression is that Moagmi is a professional and no-nonsense company

Wrong impression. shuld be clear by " "highest resolution" of all their coaxial cables"

 

[JensenW]

It is always the preferred option. compared to something with less symmetry (like twisted pair.)

Thanks for your reply. May I ask if the cable above is considered a coaxial cable or a twisted pair? A little confused here because it looks like a twisted pair in a coaxial design. This cable has a little brother which only has one conductor inside (below)

Which one would be the better cable for RCA, will they have the same shielding capability?

 

[Killingbeans]

The first one for balanced XLR (yes, it's twisted pair), and the other for RCA.

But don't waste your money on nonsense like that. You don't need silver, neither in the shield nor in the conductor. And those two voodoo-layers? Miler film? Carbon semiconductor layer? Don't let ridiculous technobabble like that sway you.

EDIT: The "skin layer" might just be there for practical reasons, so I removed it form my voodoo list.

 

[JensenW]

The first one for balanced XLR (yes, it's twisted pair), and the other for RCA.

But don't waste your money on nonsense like that. You don't need silver, neither in the shield nor in the conductor. And those three voodoo-layers? Miler film? Carbon semiconductor layer? Skin layer? Don't let ridiculous technobabble like that sway you.

These cables are too expensive for me anyway! I chose to take these two cables as an example because they are exactly alike except that one has one conductor and the other has two conductors, so it is easier to isolate my questions to a single point under examination. But I'm not buying them, haha! I'm sure there are much more practical coaxial cables I can use, which are easy to buy too. Thanks!

 

[Lambda]

Star quad cable - Wikipedia

en.wikipedia.org

This is for the special case of star quad but same principles apply.
You want the geometric center(s) for your conductor to be at the same point or as closes as possible at the same point.

With coaxial this is easy the geometric center is always the cable center. =ideal
With Twisted pair this geometric center is not exactly at the center, but with the twist it is on average in the center. =ok
Star quad is the improvement Twisted pair. tow Twisted pair making sure geometric center is in the middel. = ideal for balanced signals.

 

[MCH]

Hey all, i am in the process of assembling a diy streamer/amp (basically a pi and an amp board inside of a plastic box). Had not given it a thought but this thread made me think... for such a situation (10 cm run but surrounded by electronics) what is the best way/type of cable to connect pi to amp? I was thinking it would be completely irrelevant but just in case....

 

[Lambda]

what is the best way/type of cable to connect pi to amp?

pi to amp?
you mean dac to amp?!

https://www.neutrik.com/de/neutrik/produkte/xlr-steckverbinder/xlr-kabelsteckverbinder/emc-serie

Starquad cabel and Ferrite clamps/beads.

 

[MCH]

pi to amp?
you mean dac to amp?!

https://www.neutrik.com/de/neutrik/produkte/xlr-steckverbinder/xlr-kabelsteckverbinder/emc-serie

Starquad cabel and Ferrite clamps/beads.

Oh yes, sorry, hat dac to amp.
But your link is for xlr connectors, mine must be rca or solder. But no worries, will look for a starquad cable and try to squeeze a couple of ferrite clamps. Are these necessary or just extra protection?

 

[Lambda]

Are these necessary or just extra protection?

Depends... more like extra protection.

mine must be rca

But no worries, will look for a starquad cable

star-quad makes only sens for balanced! if you use RCA go with coax.

 

[mansr]

Miler film?

What, this stuff?

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[kongwee]

Shielded or twisted pair. That is the minimum I look for. I just find people who can make Belden cable, because of detailed spec.

 

[Audiofire]

1. Coaxial with shield and single central conductor (eg. Oyaide FTVS-510, just an example, not saying I'm eyeing this particular cable)
2. Coaxial with shield and a pair of central conductors (eg. Oyaide FTVS-910)
3. Twisted pair of conductors with a shield (eg. Grimm TPR)
4. Pair of conductors each in its PVC sheath running parallel

For (1), if I terminate the central conductor (+) to the central RCA pin and the shield (-) to the sleeve, does it mean that the shield is simply just a negative wire and not performing as a shield, and is thus no different from (4)?

The only one of those options that offers a proper construction in terms of dielectric properties and capacitance is number 1. The shield works for a "negative" wire and it is probably a good idea to add aluminum foil on top, since the shield is then the neutral wire that is supposed to have low nominal voltage. More in my slightly messy post here:

Using a 75 ohm RCA video cable for as an analog audio cable.

Faraday shielding # Faraday cage. Here’s an intermediate level description: http://g3rbj.co.uk/wp-content/uploads/2016/05/Eddy-Currents-final-2.pdf

audiosciencereview.com

 

[Dean N.]

Hi everyone, long time lurker, first time poster here. A few questions about a line level RCA interconnect:

1) If a single conductor (Conductor + shield) coax cable uses the shield as return, doesn't the cable lose its shielding properties? Even the double braid BJC LC-1, isn't shielded (because the braids are touching), right?

2) Options 2 and 3 in the OP aren't really coax, are they? Wouldn't a 2 conductor coaxial design have to be triax if the shield were to function as a shield? And aren't 2 and 3 above (in the OP) pretty much the same thing?

I'd like to build a couple line level RCA interconnects that are coaxial and shielded, but can't find any examples of any or any info on how to do them. And I have searched and searched but haven't found any answers to my questions above. If any forum can provide snake-oil-free guidance, it's this one. Thanks for any help!

 

[Killingbeans]

1) If a single conductor (Conductor + shield) coax cable uses the shield as return, doesn't the cable lose its shielding properties? Even the double braid BJC LC-1, isn't shielded (because the braids are touching), right?

It's the other way around (?): https://www.dataforth.com/shield-grounding.aspx