# Any disadvantages to using twisted primary wire for RCA cables



## simplicityinsound (Feb 2, 2007)

So I hear from some very experienced installers that twisting primary wire, 16 or 18 guage, and then soldering on RCA ends gets you quite a nice set of interconnects, better than most off the shelf units as it gets you more wire than most RCA cables conductors and is more flexible and easier to manage.

I am not that well versed in this matter, so can someone educate me on this? is it a good way to go or not?


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## Darth SQ (Sep 17, 2010)

Bing,
Some other member posted this link in another thread and it's worthy of your time.
It might be useful to answering your question since one of the interconnects tested was what you are asking about. 


Bret
PPI-ART COLLECTOR

http://www.youtube.com/watch?v=SfMU-oxDGs8


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## Justin Zazzi (May 28, 2012)

Twisted pair wire *only* works if the equipment downstream has a balanced architecture. The system works by purposefully allowing noise to enter both wires equally so that a transformer or other circuit built into the gear downstream can reject the noise equally, allowing the signal to pass cleanly. Since almost all aftermarket car audio gear does not have this feature, twisted pair RCA cables are almost always useless in aftermarket car audio. However new cars are using balanced cables more frequently and this trend may change over time.

Also, RCA cables do not pass any significant amount of current so having a larger gauge wire does not relate to any increase in performance. I have no doubt that using the method suggested can result in very nice looking and handling cables that are also cheaper than some aftermarket models, but the goal is noise rejection right?

A coaxial cable (a center conductor carrying the signal surrounded by a metal shield) is going to be the best for the vast majority of us for many years to come. You can certainly make great cables for cheap by purchasing coaxial cable and rca connectors in bulk, plus it looks awesome to have perfect lengths for custom installs ... but generally stay away from twisted pairs unless modifying twisted pair factory wiring.

The youtube video from Wirez illustrates this well.

-J


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## clix`g35 (Aug 23, 2009)

Bing, 

I think you would be better off with something like this cheap ($.27 a foot) Gepco twisted pair with a foil shield. You can run a balanced line, and solder the foil to the Source ground. 

Gepco Gepco 61801EZ Analog Audio Twisted Pair Stranded 1-Pair Cable Bulk Audio Cable at Markertek.com

If you do have the rare combination of Balanced Source with an amp that has balanced input and output, the cable will work as a balanced line, with the benefit of dumping RFI interference at the source ground. In the case that your equipment isn't balanced your cable is properly shielded. 

This subject is covered extensively in the thread below. There is a link in there somewhere to a comparison done by Blue Jean Cables .com where they compared the shielding and capacitance in different cables, coaxial has the best shielding but cannot run balanced. For someone who has to make a cable for most applications I think a shielded twisted pair is probably your best bet. 

http://www.diymobileaudio.com/forum/how-articles-provided-our-members/8158-making-rca-cables.html


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## minbari (Mar 3, 2011)

Jazzi said:


> Twisted pair wire *only* works if the equipment downstream has a balanced architecture. The system works by purposefully allowing noise to enter both wires equally so that a transformer or other circuit built into the gear downstream can reject the noise equally, allowing the signal to pass cleanly. Since almost all aftermarket car audio gear does not have this feature, twisted pair RCA cables are almost always useless in aftermarket car audio. However new cars are using balanced cables more frequently and this trend may change over time.
> 
> Also, RCA cables do not pass any significant amount of current so having a larger gauge wire does not relate to any increase in performance. I have no doubt that using the method suggested can result in very nice looking and handling cables that are also cheaper than some aftermarket models, but the goal is noise rejection right?
> 
> ...


^^This. if you dont have any noise in the system you might not notice. but technically, twisted pair is only beneficial for balanced line. if you use unbalanced, you should use a more traditional shielded cable.


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## Jfreak (Dec 20, 2012)

Mogami mic cable is another good option.


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## simplicityinsound (Feb 2, 2007)

So Is the answer then no I should NOT use twisted primary wire as rca cables? 

Sent from my SAMSUNG-SGH-I317 using Tapatalk 2


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## chad (Jun 30, 2005)

Mogami is a pain in the ass to work with and overkill in a situation where it will not be in constant movement, I vote for the Gepco, you can get it cheaper as a dealer and it comes in a myriad of colors, a bundle in techflex is still super flexible due to its jacket.


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## chad (Jun 30, 2005)

PPI-ART COLLECTOR said:


> Bing,
> Some other member posted this link in another thread and it's worthy of your time.
> It might be useful to answering your question since one of the interconnects tested was what you are asking about.
> 
> ...


Ummmm, false test.

The input impedance of the amplifier is MAGNITUDES higher than that of the output impedance of the source. Note that the end that the source WOULD be attached to is not terminated. also, the shield of modern amps is almost never true ground.

For this test to be valid the source end MUST be terminated with at least a resistor.


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## simplicityinsound (Feb 2, 2007)

so back to my original question.


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## RNBRAD (Oct 30, 2012)

You can use it, just make sure it is also shielded.


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## minbari (Mar 3, 2011)

simplicityinsound said:


> so back to my original question.


sure you can use it and you might not have noise. if you do have noise, that would be my first suspect.


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## sqshoestring (Jun 19, 2007)

Most computer networks (cat5) used twisted pair. The wire is twisted so each one picks up the same amount of noise, such as if the wire is next to a noise source. Many cables are also shielded. Twisted is useless if not using a balanced signal. Shields must be grounded at both ends, but most amps are not a real ground because the shield is used as a ground for the signal. That is why things can get strange if the shield blows out on the HU rca. Most amps have a resistor and maybe caps in the circuit to ground on the shield...they handle it different ways. If a HU makes a 2v signal it is only 2v to the HU ground, maybe not to some other ground. If you want twisted cause it looks cool that is fine, just make sure it is also shielded. Don't use bare wire twisted if you want to shield against noise.


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## miniSQ (Aug 4, 2009)

simplicityinsound said:


> so back to my original question.


Ever work with these guys? 

Contact Information -- Blue Jeans Cable

If you ever want to spend an hour discussing cables and cable theory...they are the "simplicity in sound" of cable. Not slighting any of the guru's on this site...but they are the experts...and if you ever want a dedicated cable vendor...you could do worse.


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## clix`g35 (Aug 23, 2009)

You should also check out Raw Cable, they are Blue Jeans cable, same address and phone number, only difference is they do not sell assembled cables, they only sell raw cable components.

Raw Cable -- Cable, Connectors, and Tools

Just read the bottom of the contact page were they confirm this.


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## rton20s (Feb 14, 2011)

I'll check out the Wirez video when I have time later, but I have checked out the video from D'Amore on the subject...

Truth about RCA signal cables - YouTube


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## chad (Jun 30, 2005)

rton20s said:


> I'll check out the Wirez video when I have time later, but I have checked out the video from D'Amore on the subject...
> 
> Truth about RCA signal cables - YouTube


Kinda not really, in order for the differential input to achieve any kind of CMRR the output impedance of both legs of the twisted pair has to be equal. that is not the case with most output schemes unless you mod them to have a balanced impedance.


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## req (Aug 4, 2007)

the problem with that video up there is that it is ONLY for RADIATED noise inducted into the wire from another wire or source like a fuel pump, AC fan or something.

any noise feedback within the power circuit will still cause noise


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## DAT (Oct 8, 2006)

Yeah, test is good for guys that do not know he is tricking you.

Bing, I would use any wire and ground on one end ( source ) and not on the other end of the cable...

You'll be set


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## req (Aug 4, 2007)

yea, same as DAT said. i have been looking for a good signal cable with a shield (foil+wire).

(foil shield \ braid shield \ dielectric \ (jacket(conductor1)jacket) (jacket(conductor2)jacket)

then you just solder a jumper wire at the source end to the braided shield when making the cable, and ground it where the head unit is grounded and you have yourself a faraday cage.

Faraday cage - Wikipedia, the free encyclopedia

this shield really is only good for radiated sound - and that is already not very usual in a car as opposed to feedback through the circuit, so like they said and * to answer your question - a twisted pair in the middle is fine - but it wont help reject noise unless the signal is balanced.*



req said:


> perfect.
> 
> what you COULD do, is put the shielding all the way to the connector - then solder the drain wire down at the split. that way it wouldnt be totally rediclious. and for multichannel, just put the drain way down where all the ends split from the main body.


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## Eric Stevens (Dec 29, 2007)

simplicityinsound said:


> So I hear from some very experienced installers that twisting primary wire, 16 or 18 guage, and then soldering on RCA ends gets you quite a nice set of interconnects, better than most off the shelf units as it gets you more wire than most RCA cables conductors and is more flexible and easier to manage.
> 
> I am not that well versed in this matter, so can someone educate me on this? is it a good way to go or not?



Bing,

For a signal cable to be conisdered good it should have low capacitance and low inductance as well so it isnt coloring the sound with any filtering effects. Even for very long runs in prosound they rarely use a conductor larger than 22ga and typically a smaller guage. 

Anyone saying that twisted pair cables wont give you better noise rejection than a coaxial cable has not studied all the facts yet. Or they are using flawed testing metods to give erroneous results. AT&T uses twisted pair over very long runs (as in miles) to prevent noise getting on phone lines, twisted pairs are used in Cat 5/6 data cables with different number of twists per inch to give the best noise rejection for the frequency band intended for those pairs. 

The 100% foil shield with a drain like that used in Belden or Gepco linked earlier in the thread just give it all that much better noise rejection.

Back in the early 90's I embarrassed a Monster Cable rep at a local dealer who was using their old noise tester to show how their twisted pair cables were better than the coaxial cables from Streetwires and Phoenix Gold etc. I bet him lunch that I had a cable that was quieter than Monster 401XLN (or something like that ) and I used monster cable RCA connectors too. I won the challenge clearly and the cable I used was a Belden 8451 I think.

I suggest a good mic or audio cable like the Belden or Gepco.

Eric


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## minbari (Mar 3, 2011)

Eric Stevens said:


> Bing,
> 
> For a signal cable to be conisdered good it should have low capacitance and low inductance as well so it isnt coloring the sound with any filtering effects. Even for very long runs in prosound they rarely use a conductor larger than 22ga and typically a smaller guage.
> 
> ...


not that I disagree with most of what you say, but telephone lines are balanced and 48 volts of signal. you get the advantage of a balanced line, which inherently rejects noise and since the signal lever is soo high you need alot of noise to over ride the signal.

same goes for ethernet, you have a TX pair and an RX pair.

If he is not using balanced line, then twisted pair has no benefit. plus we are talking about 2-5volts on avg and not 50.


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## bbfoto (Aug 28, 2005)

simplicityinsound said:


> So Is the answer then no I should NOT use twisted primary wire as rca cables?


You CAN use the twisted primary wire for your RCA cables, BUT it will only REJECT INDUCTED NOISE if you are connecting a BALANCED Source to another BALANCED component (amp or processor, etc.). So it's only for use in "balanced component systems".

To REJECT INDUCTED NOISE between two UNBALANCED components (the majority of aftermarket head units and amplifiers), you need a very complete and robust outer SHIELD that is terminated properly at each end. A twisted pair wire configuration does not provide much benefit here.

The advantage of the GEPCO wire that was suggested is that it has BOTH attributes combined...It has Twisted Pair conductors AND a good Outer Shield. So it is an "all-in-one" cable, making it the most versatile cable if you just want buy one type of cable for simplicity's sake (pun intended) that you can use in Balanced OR Unbalanced systems.

Also as mentioned, the GEPCO cable has the advantage (over using just the simple twisted primary wire) of a possible further reduction of INDUCTED NOISE when used in BALANCED SYSTEMS, due to the Outer Shield which will reject noise that the inner twisted pair wires would otherwise pick up, provided that this outer shield is terminated properly at each end.

CONCLUSION: Therefore, the GEPCO 61801EZ cable is technically and cost-effectively one of the best one-product solutions to use to make custom-length RCA interconnects for EITHER Balanced OR Unbalanced setups.

I realize that all of these points were already covered in the above posts. I just tried to put it all in one post and "word" it so it is easier to understand. I hope this was successful.

Side note: What RCA ends do people recommend? My research says that the Canare RCAP crimp connectors would be best. Any thoughts? Chad or others?


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## minbari (Mar 3, 2011)

cajunner said:


> okay, so the twisted pair RCA's that were so popular just a few years back, are no good?


not a matter of "no good" they just dont reject noise. people see twisted pair in everything and decide it must be better without knowing how it really works. why do so many people think mega farad caps give you more bass?


> and, when we're talking balanced, are we talking about the Coustic approach, or the old BLT SoundStream approach?
> 
> And if it's Zapco, aren't the symbilink cables a part of their system and there's no insertion point for a pair of twisted RCA's anyway?


balanced is balanced. you have a differential output and a summing amplifier at the other end.


> And what sources do have balanced outputs?
> 
> and what amps accept balanced inputs, in any configuration?


come, on do you really want people to start naming them all? 

I have a feeling you are being somewhat sarcastic as I know you are a smart guy, so most of this is not new information


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## Eric Stevens (Dec 29, 2007)

minbari said:


> not that I disagree with most of what you say, but telephone lines are balanced and 48 volts of signal. you get the advantage of a balanced line, which inherently rejects noise and since the signal lever is soo high you need alot of noise to over ride the signal.
> 
> same goes for ethernet, you have a TX pair and an RX pair.
> 
> If he is not using balanced line, then twisted pair has no benefit. plus we are talking about 2-5volts on avg and not 50.


You sir are quite right. 

After reviewing some availble information I think the most important factor is "shielded" and with a drain wire properly terminated even better.

Eric


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## rton20s (Feb 14, 2011)

I'd like to see a complete list... if you have the time minbari? 

So what type of RCA should I be running if I have an unbalanced (Single Ended) output head unit (DEH-80PRS) and a balanced (differential) input amplifier (KS900.6)? And the only negative of running the incorrect type is the possibility of introducing (more) noise to the system?


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## minbari (Mar 3, 2011)

rton20s said:


> I'd like to see a complete list... if you have the time minbari?
> 
> So what type of RCA should I be running if I have an unbalanced (Single Ended) output head unit (DEH-80PRS) and a balanced (differential) input amplifier (KS900.6)? And the only negative of running the incorrect type is the possibility of introducing (more) noise to the system?


lol, I get the list started? 

JL audio


shielded. if the output of the head end is unbalanced, then it will be sending a signal that is referenced to ground. The input to the amplifier will still work that way, just not deferentially.


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## chad (Jun 30, 2005)

cajunner said:


> And what sources do have balanced outputs?


All of them with 50 cents in passive components and a soldering iron.


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## sqshoestring (Jun 19, 2007)

Or iirc you can get a balanced rig to go behind the HU and run to the amps. Its cool I suppose, but when I have a big noise problem I can't handle I'll look into going that way.


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## chad (Jun 30, 2005)

sqshoestring said:


> Or iirc you can get a balanced rig to go behind the HU and run to the amps. Its cool I suppose, but when I have a big noise problem I can't handle I'll look into going that way.


All you have to do is give the "inverting" line that would have been the shield of the RCA the same impedance characteristics as the driven line. it will be 3dB down from true differential and the same level as the original, but given that both lines will have the same impedance characteristics the CMRR will rock.


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## bbfoto (Aug 28, 2005)

Originally Posted by*cajunner: And what sources do have balanced outputs?



chad said:


> All of them with 50 cents in passive components and a soldering iron.



I could guess and be wrong, so would you mind spoon-feeding us just once more by providing a link to a simple schematic and parts list? I'd hit the "THANKS" button if it still existed.


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## req (Aug 4, 2007)

honestly any of these signal cable types should work.

Microphone Cable & Signal Cable in the Wire & Cables Department at Parts Express | 1610

*again, twisting the wire is not bad and will do zero harm, it just does not reject noise if it is unbalanced*

but adding a *GROUNDED SHIELD* will help. if the shield is not grounded, well, then it is as good as the twisted pair.


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## cjazzy4 (Mar 29, 2012)

I think I missed something along the way.......*Direct me or fill me in*.......So twisted RCAs and/or twisted speaker wire only reject noise if they are balanced.......How do you make them balanced? Is there something more that has to be purchased?


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## cjazzy4 (Mar 29, 2012)

req said:


> honestly any of these signal cable types should work.
> 
> Microphone Cable & Signal Cable in the Wire & Cables Department at Parts Express | 1610
> 
> ...


So are you saying that using this wire as a speaker wire to connect your speakers in the car reduces noises and provide the best signal path for gear (speakers, amps, HU)?


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## req (Aug 4, 2007)

not speaker wire.

signal wire.


speaker wire is high voltage (well, for a stereo it is like 10AC volts this is just a guesstimate, maybe for a subwoofer. but it varies) and signal wire is low voltage (like 1AC volt. some preamps can do 6 or 8 volts... and most of the time when the volume is low or the preamp sucks, it is even lower in the milivolts)

the wire you use must be rated to carry that current and voltage over the distance required, therefore larger voltage\current for speakers will need higher thickness (guage) wires, also - since the voltage is higher - any induced noice will have to be significantly stronger to overcome the higher voltage of the speaker level signal.

conversly, a signal wire (RCA usually) has a very small signal, low voltage and current. there should be low capatance and inductance (reall in all wires to be honest) so there are no "built in crossovers" from the wires specifications, and it does not need to be nearly as thick. the problem with the small signal, is that induced noise (lets say from the air conditioning motor) can mess with the signal because it is so weak. to solve this, we can put a faraday shield around the wire and ground it - so that the shield absorbs the noise, and the signal inside remains unchanged. a big example of this is an elevator, when you get inside an elevator - your cellphone signal usually drops off because the whole thing is a big metal cage that is grounded to the steel wire and ultimatly the building and earth. this box blocks radio frequency waves that your cellphone uses - just pretend that the elevator cabin is the shield on the wire, and your cellphone is the cd player\speaker, and the cell phone tower is the radiated noise.

the most important part is grounding the shield.


*will twisting wires ever diminish a wire quality? prolly not.
will adding a shield ever diminish a wire quality? prolly not.
will doing both these things raise the cost of the wire? most likely.

using twisted pairs for a BALANCED signal like a zapco symbalink or a XLR interface helps reject noise.

using a GROUNDED shield on an UNBALANCED signal will help reject noise.

this works for every wire on a basic level - but the higher the voltage, the harder it is to induce noise.*


most of the time, however - noise in a car stereo is NOT INDUCED BY RADIATION, it is a circuit feedback from something like the alternator or some other component in the car or the stereo system. so no amount of shielding is going to stop it. at that point, its a ground loop or a component is faulty - and it is a huge pain in the ass to locate.


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## chad (Jun 30, 2005)

bbfoto said:


> I could guess and be wrong, so would you mind spoon-feeding us just once more by providing a link to a simple schematic and parts list? I'd hit the "THANKS" button if it still existed.


http://www.jensen-transformers.com/an/an003.pdf

Notably figure 2.4 but the whole thing is a good read.


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## cjazzy4 (Mar 29, 2012)

req said:


> not speaker wire.
> 
> signal wire.
> 
> ...


Thank you for clearing that up for me.....I understand....I got a build coming up and chose to get the twisted wire (rca,speaker) over the regular wire (company called NVX).....At this point want to make sure I get the best quality for my budget.


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## bbfoto (Aug 28, 2005)

Thanks Chad! Excellent! However, the Jensen products are not quite just 50 cents in passive components.  But the schematics are there, thanks! 

Thanks Andy and everyone else, too. It's good to have this info all in one thread.

Now, is it possible to create a clean, isolated 12VDC power "system" within our vehicles with similar or other components? Basically, completely filtering & isolating the electrical system much as a 120VAC Double-Conversion Pure Sine Wave Inverter/UPS does for our household computer & electrical components?

Would something like this work, or not?

http://www.hlabs.com/products/fluxpower/

Maybe this should be a separate thread with appropriate title...?


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## chad (Jun 30, 2005)

Right. but impedance balancing the output allows you t properly utilize a differential input and twisted pair.


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## sqshoestring (Jun 19, 2007)

I recall in the 80s noise issues were terrible. Today I run the power cable right next to the RCA, not going to waste my time tearing into the other side of the car until I need to lol. With ECUs in cars, modern tech, better equipment....I rarely have noise issues, have not for a long time. Not saying it does not happen, just hard to see why you need to go to such great lengths to get away from it. You likely have a crappy amp or HU, and I don't care what name is on the front some old school amps were terrible with noise issues and people still think they are made of platinum today. Of course some HU had 1V outputs back then too.


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## chad (Jun 30, 2005)

My car is particularly electrically noisy, like a ford truck  Some are noisier that others. 

Also, why not do it?

One reason for the noise issues in the 80's was not output voltage at all, it's the higher impedance outputs and the fact that many amps and processors had grounded shields which caused a differential in voltage and subsequently enough current to induce a hell of a lot of noise.


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