Use Canare L-4E6AT for RCA connection?

[stonemarten]

Dear experts,

I would have your opinion on using the Canare L-4E6AT balanced cable for build an RCA cable. I have some leftover and would reuse it...

I'm thinking to connect the blue to +, white and shield to -, together: is that correct?
Is it a good solution for the best sound or do I need to buy a specific RCA cable?
If yes, what do you recommend (Canare is more available here than blue jeans...)?

thanks for the help!

cheers

 

[WaynePflughaupt]

Not making sense of your connection scheme there.

There are a few options for termination, all assuming the shield is used for signal (-):

• Tie all blues and whites together for the (+).
• Use both of one color for (+) – pick one – and tie both of the other color into the shield.
• Use both of one color (again, pick one) for the (+), clip the other two and don’t use them.
• Use a single lead of one color and clip the other three.

Regards,
Wayne A. Pflughaupt

 

[stonemarten]

Wayne,

thanks very much for your suggestion

• Use both of one color for (+) – pick one – and tie both of the other color into the shield.

if I understand well:
- 2 wires of the same colour for (+)
- 2 wires of the other colour and the shield together for the (-)

is that correct?

thanks!

cheers

 

[Speedskater]

A star-quad shielded cable is great for a XLR balanced interconnect in high noise areas (like near a theater lighting system).
While not my first choice, it will work for shorter unbalanced RCA interconnects (say 5 meters/15 feet). It's had to work with all those wires in a little RCA connector.

Method A:
One Blue wire as center conductor.
The three other wires to the shell at both ends.
The shield to the shell at both ends.

Method B:
One Blue wire as center conductor.
The three other wires to the shell at both ends.
The shield to the shell at the send end only.

 

[WaynePflughaupt]

if I understand well:
- 2 wires of the same colour for (+)
- 2 wires of the other colour and the shield together for the (-)

is that correct?

Yes.

Regards,
Wayne A. Pflughaupt

 

[Johnny2Bad]

The Canare L4ES is a great cable to serve as a building block for inexpensive RCA interconnects. Commonly known as "Star Quad" cable, it's designed for microphones and long cable runs; as such it deals well with low signal levels and has low capacitance, both good qualities in an unbalanced interconnect. You can even use it as a cartridge > phono preamp cable, which is something you can't say about every RCA-RCA cable.

Treat the four signal-carrying wires as two pairs ... I believe they are blue/blue and white/white, but whatever ... marry the two same coloured pairs at each RCA connector, so that 2x blue = positive (centre) connectors and the two white = negative (outer) connectors. (Exactly which colour pair you use for positive and negative is up to you, but for the sake of consistency use one configuration and stick to it for all the cables you make for this purpose, so (for example) you can make repairs if necessary without resorting to needing a continuity tester).

The shield should be connected to the negative (outer) RCA at one end only, and left floating at the other end (trimmed and not connected, which means covering it with shrink wrap so it doesn't contact the barrel of the RCA, which is also connected to negative / ground of a metal RCA connector).

Mark the end where the shield is connected; this is the source end. For example, if used for a preamp to power amp connection, the shield would be connected at the preamp output RCA and left floating at the power amp input RCA.

I prefer the very similarly constructed and slightly more expensive Mogami Star Quad cable but the Canare is no slouch. Both cables are manufactured in Japan.

Properly constructed the RCA > Canare L4ES > RCA is a very good basic performing cable equivalent to commercial cables of roughly $50~100 retail / 1 M pair, and because the cable itself is reasonably inexpensive (about $US 1 a foot) for longer lengths it's quite a bit more economical than commercial cables where they tend to charge $5 or more per foot for longer lengths for cables of equivalent quality.

Shielded cables are not necessarily mandatory but they do reduce induced interference (EMI, and RFI) so are not a bad idea in many cases where our modern world means ever-increasing radio interference sources in the home.

There is a remarkably large number of members here on Audioholics who mock the value of any non-electrical properties of a cable, or have strict "lines in the sand" where they will propose any improvement in a certain property is irrelevant, but for what it's worth a good quality microphone cable has the electrical properties that are valuable in an interconnect and in a microphone application will be designed specifically for low handling noise, which does affect cable performance, despite what the nay-sayers may offer as evidence you have gone insane. And if you are one who agrees with them, well, you get borh for free with the Star Quads.

 

[stonemarten]

All,

thanks very much for the inputs, I really appreciate!!

Johnny2Bad,

The Canare L4ES is a great cable to serve as a building block ...

thanks for the great explanation and details, really helpful! It's interesting that you connect the shield to one end only, very new to me.
About the usage, this is a pre-amp to digital crossover cable.

cheers

 

[Johnny2Bad]

All,

thanks very much for the inputs, I really appreciate!!

Johnny2Bad,



thanks for the great explanation and details, really helpful! It's interesting that you connect the shield to one end only, very new to me.
About the usage, this is a pre-amp to digital crossover cable.

cheers

By connecting the shield at the input end you are protecting the internal wires (those surrounded by the shield) from EMI and RFI, which is the purpose of a shield in the first place, and by not connecting the shield at the output end, you are minimizing the effect of the shield as an electrical connection, insuring that the signal return is through the same diameter and number of connectors as the signal positive.

In essence you have extended the grounded chassis of the source component all the way to the input of the connected component, but you haven't connected the two chassis together via the shield, which can lead to hum or other ground loop issues.

The "loop" is created when you connect a ground for the two components via the AC cord and the interconnect; what you want is one or the other, but not both. Since it's far from trivial to remove the power cord ground, we instead choose to remove the interconnect ground, which breaks the loop (and is what we want).

There are cases where you do want to connect the grounds via the interconnect, but in that case you might want to look at a coaxial interconnect instead of the construction used in the Canare L4ES.

 

[jinjuku]

There is a remarkably large number of members here on Audioholics who mock the value of any non-electrical properties of a cable, or have strict "lines in the sand" where they will propose any improvement in a certain property is irrelevant, but for what it's worth a good quality microphone cable has the electrical properties that are valuable in an interconnect and in a microphone application will be designed specifically for low handling noise, which does affect cable performance, despite what the nay-sayers may offer as evidence you have gone insane. And if you are one who agrees with them, well, you get borh for free with the Star Quads.

I don't think any AH'er here poo-pooh's a well constructed cable. I think the outlandish claims and absurd pricing there of is where AH'ers make noise.

I've more than once recommended star quad cabling from Mogami/Canare.

Belden 1172A is also nice but a bit on the expensive side (comparatively).

At least these outfits post the measurements of how their products perform. In a home environment star quad is overkill but it's certainly not cost prohibitive.

 

[Johnny2Bad]

I don't think any AH'er here poo-pooh's a well constructed cable. I think the outlandish claims and absurd pricing there of is where AH'ers make noise.

I've more than once recommended star quad cabling from Mogami/Canare.

Belden 1172A is also nice but a bit on the expensive side (comparatively).

At least these outfits post the measurements of how their products perform. In a home environment star quad is overkill but it's certainly not cost prohibitive.

" ... in a microphone application will be designed specifically for low handling noise, which does affect cable performance, despite what the nay-sayers may offer as evidence you have gone insane. And if you are one who agrees with them, well, you get borh for free with the Star Quads. ..."

So you are suggesting that handling noise is an issue with interconnects, and that AH members who actively speak against what they would refer to as "Snake Oil" would agree that handling noise is an issue with interconnects?

I would be very surprised to hear that.

But if so, I guess I was wrong to suggest some members of the forum here would discount the validity of handling noise as a parameter for an interconnect.

 

[jinjuku]

" ... in a microphone application will be designed specifically for low handling noise, which does affect cable performance, despite what the nay-sayers may offer as evidence you have gone insane. And if you are one who agrees with them, well, you get borh for free with the Star Quads. ..."

So you are suggesting that handling noise is an issue with interconnects, and that AH members who actively speak against what they would refer to as "Snake Oil" would agree that handling noise is an issue with interconnects?

I would be very surprised to hear that.

But if so, I guess I was wrong to suggest some members of the forum here would discount the validity of handling noise as a parameter for an interconnect.

I have no idea where the quoted post is so I can't read the thread for context. Star Quad Cables are built for durability via redundant pairs. When I was installing live sound we used star quad for all the mic and panel interconnects due to the fact they were most likely going to suffer some abuse.

They aren't needed for a home application. I'm happy with my 18AWG, 98% copper braided shield, Mono-price mic cable for the house. It certainly wasn't bettered by some $300 AQ/KK XLR's.

 

[Johnny2Bad]

The Star-Quad construction is a form of twisted-pair construction primarily designed to increase resistance to Electromagnetic and Radio Frequency noise. It is not intended as a form of redundancy to account for cable strand breakage.

With your experience in microphone installations, have you never experienced Tribo-electric noise (noise generated with handling or bending of cables)?

 

[jinjuku]

I understand the CMNR nature of quad star vs normal mic cable. One of the benefits is that it's more resistant to breakage and if you have a failure in a part of a pair the cable will still function.

I've honestly never been in a situation where we had to swap out cabling for noise issues unless there was damage to the cable that rendered it non-operational or terminated incorrectly.

 

[WaynePflughaupt]

With your experience in microphone installations, have you never experienced Tribo-electric noise (noise generated with handling or bending of cables)?

Yes.

Regards,
Wayne A. Pflughaupt

 

[Johnny2Bad]

RE:

... {snip} ...
Johnny2Bad,
... {snip} ...
It's interesting that you connect the shield to one end only, very new to me.... {snip} ...

None other than Henry W Ott in his seminal work " Noise Reduction Techniques in Electronic Systems" which is the "Bible" on the subject, states:

" ... a shielded cable grounded on one end has 84dB of attenuation to magnetic noise and much more for electric, while if the shield is grounded at both ends the attenuation is more like 36dB". ..."

Now, I am aware that a shield so connected can also act as a stub antenna, which could introduce radio broadcasts into the system, but the lengths we commonly use for interconnects don't really correspond to a frequency likely to be encountered even in urban environments, so it's rarely an issue (and you will know it as soon as you use the cable, so it's not like it will be a mystery if there is a problem or not).

To correct, if you do get a DJ or a taxi driver coming out of your speakers, change the length (remove a few inches from the open end RCA and re-solder). Alternately you can connect a small value capacitor at the open end shield to ground (negative terminal, or barrel) on the RCA.

 

[highfigh]

RE:


None other than Henry W Ott in his seminal work " Noise Reduction Techniques in Electronic Systems" which is the "Bible" on the subject, states:

" ... a shielded cable grounded on one end has 84dB of attenuation to magnetic noise and much more for electric, while if the shield is grounded at both ends the attenuation is more like 36dB". ..."

Now, I am aware that a shield so connected can also act as a stub antenna, which could introduce radio broadcasts into the system, but the lengths we commonly use for interconnects don't really correspond to a frequency likely to be encountered even in urban environments, so it's rarely an issue (and you will know it as soon as you use the cable, so it's not like it will be a mystery if there is a problem or not).

To correct, if you do get a DJ or a taxi driver coming out of your speakers, change the length (remove a few inches from the open end RCA and re-solder). Alternately you can connect a small value capacitor at the open end shield to ground (negative terminal, or barrel) on the RCA.

The point of having one end grounded is so the shield CAN act as an antenna and when the signal on the shield coincides with the ground, it will be eliminated (assuming the ground in the building's electrical service is of high integrity). If there's any measurable resistance, that antenna works pretty darn well, as demonstrated by a lot of guitar/amp rigs and PA systems. So many people (and musicians) think that a new cable will fix all of their noise problems when the whole grounding path from instrument to Earth must be seen as one conductor. Radio stations? Check. Buzz from dimmers? Check. Clicks & pops from switches? Check. Clean/tighten/resolder the connections in the ground path to elminate/minimize the problems? Yup.

 

[Speedskater]

RE:


None other than Henry W Ott in his seminal work " Noise Reduction Techniques in Electronic Systems" which is the "Bible" on the subject, states:
" ... a shielded cable grounded on one end has 84dB of attenuation to magnetic noise and much more for electric, while if the shield is grounded at both ends the attenuation is more like 36dB". ..."

I have had that old book on my bookshelf for over 30 years (first edition). What page would that statement be on?

Note that his much larger new (2009) book is "Electromagnetic Compatibility Engineering".
http://www.hottconsultants.com/EMCE_book_files/emce_book.html

 

[Johnny2Bad]

The point of having one end grounded is so the shield CAN act as an antenna and when the signal on the shield coincides with the ground, it will be eliminated (assuming the ground in the building's electrical service is of high integrity). If there's any measurable resistance, that antenna works pretty darn well, as demonstrated by a lot of guitar/amp rigs and PA systems. So many people (and musicians) think that a new cable will fix all of their noise problems when the whole grounding path from instrument to Earth must be seen as one conductor. Radio stations? Check. Buzz from dimmers? Check. Clicks & pops from switches? Check. Clean/tighten/resolder the connections in the ground path to elminate/minimize the problems? Yup.

I do not understand your post.

*If* a shield (or conductor or even a PCB transmission line - signal trace over a ground plane trace on a multi-layer PCB) act as an antenna, then whatever broadcast corresponding to the frequency (fraction or multiple) of the length of that antenna will be picked up and you will hear it through your HiFi rig (assuming that frequency is in use). We do not want that.

As for the "whole grounding path from [component] to earth" goes, any 3-prong AC cord connected component will have that path established through the AC ground. You do not want to establish a second ground path in the interconnects, as you are well aware, doing so will construct a ground loop which is what you do not want.

Some source components (disc players for example) do not employ a 3-prong NEMA AC connector, but leaving that particular chassis ground floating usually isn't a problem. In that case there typically will be ground path via the chassis ground which is again typically connected to and carried by the (-) signal line to the downstream component, whereupon it's ground path will then be established " from [component] to earth" via that downstream NEMA-15 3-prong AC connection.

 

[Johnny2Bad]

I have had that old book on my bookshelf for over 30 years (first edition). What page would that statement be on?

Note that his much larger new (2009) book is "Electromagnetic Compatibility Engineering".
http://www.hottconsultants.com/EMCE_book_files/emce_book.html

Well, either you could read it, or sell it. The original edition in good used condition sells online for over $100, may as well make use of it one way or another.

 

[Speedskater]

Well, either you could read it, or sell it. The original edition in good used condition sells online for over $100, may as well make use of it one way or another.

The question was:
"What page would that statement be on?"