Unshielded RCA cable is bad design

Here is a bit long article about HIFI system interconnect cables. There are pages promoting use of different unshielded cable constructions for HIFI systems interconnections. But the truth is that unshielded RCA cable is bad design and should be avoided. This article tells the truth about unshielded RCA cables, why they are bad and how many pages promoting them are wrong.

Nearly any signal that uses RCA connectors are considered line level. These are very weak signals (0.1-2V) and will pick up noise easily (unbalanced, output impedance can be up to 5000 ohms). RCA connectors are also used to carry sometimes phono signals, those are even weaker and will pick up noise even more easily than line level signals.

Interconnects with RCA plugs should be made with coax cable or shielded twisted pair cable to work well. Typically interconnects with RCA plugs are made with coax cable. The coax encases the signal wire in a pipe that protects it from interference.


Unshielded cable, like ordinary speaker wire or CAT5 UTP, is unsuitable cable for RCA interconnections. It will pick up noise very easily. This noise is usually heard as  a low level fuzz (less than totally silent background)  and obvious hum.

Your speaker level wires (with about 10-30 volts signal typically 8 ohm load impedance and fractions of ohms amplifier output) are much less sensitive to radiated noise than the RCA signal wires. That’s why they can live well without shielding.

Line level cables use considerably lower signal voltages and very much higher impedance, so they pick up noise more easily. For interconnects shielded construction is the way to go for line level RCA interconnects. Shielding on unbalanced interconnects does make a big difference in the background noise level.

Unshielded twisted pair cable, like CAT5 networking cable, is bad idea for RCA interconnects. It is true that due to its characteristic CAT5 and similar have low capacitance, but that’s where the good news end.


You might have read that that UTP cable construction has good noise rejection characteristics and can carry signals well without shielding. CAT5 cables used in a computer network system are renowned for their ability to reject unwanted noises. It is true that twisted pair geometry works for the phone companies who run miles of cable and for Ethernet LANs very well without noise problems. Unshielded twisted pair works and rejects noise in those applications well because it is used in them to carry balanced signals.

Cat 5 and similar unshielded twisted pair (UTP) cables only work effectively when run as balanced lines where there are common-mode noise rejection properties built into the system. That common mode rejection is easily accomplished when the receiving circuit is passive (headphones or loudspeaker), transformer coupled, isolated and battery operated, or otherwise not referenced in any way to the transmitting-circuit common (either capacitively or resistively connected). For best performance the signal signal sending end should have same impedance from both signal wires to ground.

When you wire unshielded twisted pair to unbalanced signal source and receiver RCA connectors, most of the good properties of the UTP cable noise rejection are lost.  Unbalanced RCA interfaces found in normal HIFI equipment do not have common-mode noise rejection properties. The coupled noise will get to the signal on the cable. Therefore UTP is not effective for unbalanced home/consumer applications.Read Cat5 cable VS RCA cable for car stereo use article if you want to see test results.

There are also special unshielded braided unshielded cable construction made for HIFI interconnects. Those suffer from the same basic problems as the unshielded twisted pair cables, although some designs might offer a slightly better noise rejection characteristics than twisted pair. But they are still poorly shielded and should be avoided.


(image from 4-Play)

Unshielded unbalanced cables are very sensitive to capacitive coupling especially when circuit impedance is high (impedance mostly determined by signal source output impedance in HIFI systems). For example power cords radiate a magnetic field and an electric field that is prone to carrying the interference that rides on all AC power lines to some extent. Shielding is an essential part of a proper RCA audio cable.  It is true that shielded cable has higher total cable capacitance than otherwise similar unshielded cable, but that’s the price you have to pay for the noise free sound.

The cable capacitance can affect the sound going through the cable. The most typical effect is that the cable capacitance together with signal source output impedance forms a low pass filter that more or less attenuates the highest frequencies. How much cable capacitance effect depends very much on the signal source output impedance (output impedance is typically in 30 ohms to 5000 ohms range, much bigger variation range than in capacitance of different audio cable types). If the signal source badly engineered, then the cable capacitance affects the signal source output driver amplifier stability, causing distortion and risk of oscillation at high cable capacitance. A well designed HIFIi equipment should be designed to cope with the normal cable capacitance. If the capacitance of normal shielded cable has considerable effect on the sound you get, there is something wrong with your signal source!

Some HIFI manufacturers (especially cable manufacturers that make such cables) say that unshielded unbalanced cables generally sound better than shielded (if your area does not have a lot of RF energy). If you are so lucky that you don’t have such noise sources nearby and like playing then you can try unshielded cable if you wish. Anyways in today’s high tech world  it is hard to find places without much RF energy nearby because for example cellular phones are very common and cause lots of noise if placed nearby unshielded cable. All well designed interconnects sound identical. Some interconnects are badly designed and do indeed sound different.

In today’s modern world you should always use shielded RCA cable. A coaxial design with a braided mesh shield is a good choice and braid shielded twisted pair is also good for making RCA cables. All well designed interconnects sound identical. Some interconnects are badly designed and do indeed sound different. Unshielded RCA cables are conceptually bad designs and should be avoided. Unshielded cables are OK only for applications that use balanced signals (professional audio), but even in those applications using shielded cables is the preferred.


  1. John Huntington says:

    Great post! There is so much audiophile nonsense out there. You might like my friend Bob McCarthy’s post too:

  2. Jacob says:

    I knew unshielded cables would really have some problems with regard to sound that’s why coaxial cables really makes a great difference in terms of the quality of output signal.

  3. tomi says:

    This site uses a custom made “theme”.

  4. trademarking says:

    I must say, I thought this was a pretty interesting read when it comes to this topic. Liked the material. . . . .

  5. Reba Zerbel says:

    Hi,I find that your web log is quite informative and useful and we wonder if there is a possibility of acquiring More articles like this on your website. If you willing to support us out, we will be willing to compensate you… , Reba Zerbel

  6. Patricia says:

    Funny, your webpage formats beautifuly on my new iPhone, didnt look quite right on my old peice of junk.

  7. Carrol Persing says:

    You got a categorically usable blog I be experiencing been here reading for nearby an hour. I am a newbie and your prosperity is hugely much an incitement representing me.

  8. Bruce McDonald says:

    In searching for sites related to web hosting and specifically comparison hosting linux plan web, your site came up.

  9. Used DJ Equipment says:

    Hi I found your blog on google and enjoyed reading it .I’ve bookmarked your site and is going to be back

  10. Rosamaria Lindenmuth says:

    haha,The Motif of your blog is very Suit to me, I hope more alternate with you this Motive.

  11. Thora Dechaine says:

    I have to state, you chose your words well. The ideas you wrote on your encounters are well placed. This is an incredible blog!

  12. online says:

    I admire what you have done here. I like the part where you say you are doing this to give back but I would assume by all the comments that this is working for you as well.

  13. Deb Milanese says:

    Good journey and experience!

  14. sex says:

    This really is my first time i visit right here. I found so many interesting stuff inside your weblog particularly its discussion. From the tons of comments on your content articles, I guess I’m not the only one having all the enjoyment here! keep up the good function.

  15. Private Server says:

    most pages on this blog are usfull to me :) bookmarked it! keep it going, good job

  16. Jon Brink says:

    There’s no way that can be true. Can it?

  17. Wayne Bumpus says:

    Hello. Good position. I did not expect this on a Wednesday. This can be a great story. Thanks!

  18. Jon Brink says:

    I really wanted to find a website that was like a facebook for audiophiles. Finally found it!

  19. Jon Brink says:

    What shows do you go to? RMAF? CEDIA? CES? High End Show? California Audio Show? Capital Audiofest?

  20. Andrew Pelt says:

    Far out….i am so cheerful that i at long last got the internet….i never thought there would likely be so much excellent info like this article…..thanks so much i will be back for more

  21. Jon Brink says:

    Loved the post. I think we share the same passion for high end audio.

  22. learning methods says:

    The way you have described this is very thorough. I will link your blog page to mine.

  23. F1 Races says:

    I truly enjoyed this. It is very educational and useful. I will return to check on upcoming posts.

  24. Cecilia Aprea says:

    Excellent work,webmaster,decent design and style!

  25. dyslexia testing says:

    found it on google. nice. ill come back to visit.

  26. Yevette Jakowich says:

    Hello, i am the admin of bleucheesefencing.com .Thank’s for sharing this info.This is very helpful and informative material.Good post and keep it up friend.

  27. Fuuny Cats says:

    Nice site template =) I love it

  28. Dwight Vaill says:

    i cant beleive i stumbled onto your post..thanks so much!!! i am going to have to sign up 2 ur RSS feed so i can keep updated with your post’s…thanks Again

  29. enhancement exercises says:

    Basically its a nice article. Yes, that is true, I agree with you, but I am not sure if there are no other options.

  30. utp cable says:

    tnx for droppin by my blog. nice post. it reminds me of my CCNA Networking class. how to create a crossover lan cable withthe use of CAT-5 Cable, RJ-45 and Crimper :D

  31. Hipolito M. Wiseman says:

    Hey, I searched for this blog on Bing and just wanted to say thanks for the excellent read. I would have to agree with it, thank you again!

  32. Jere Murdy says:

    Hey there, I’ve been reading your weblog for about a month now. So I just decided to stop lurking and say hi :)

  33. Trance Music says:

    Exceedingly great post you got here. As one blogger to another, I recognize how tough and how much energy it requires to write up something tangible and good. regard.

  34. George says:

    I’ve been running computer cabling for years, but man the prices are going up huh? I’ve been looking for some new suppliers. Any suggestions?

  35. Beatris Miguel says:

    Quite intriguing web page. Wish it will eventually constantly be alive!

  36. medical assistant says:

    Terrific work! This is the type of information that should be shared around the web. Shame on the search engines for not positioning this post higher!

  37. Edison Moorhead says:

    Enjoyed every bit of your blog article. Fantastic.

  38. Monte Oliveria says:

    Really appreciate you sharing this article.Much thanks again. Great.

  39. Types of RCA Cable says:

    Types of RCA Cable…


  40. aboo technology says:

    That is some inspirational stuff. Never knew that opinions could be this varied. Thanks for all the enthusiasm to offer such helpful information here.

  41. Jon Brink says:

    I can’t remember the last time I had so much fun reading a blog. Kudos!

  42. Jon Brink says:

    I wish there were more pictures (I admit it… I’m a photo junkie).

  43. David Laloum says:

    There is another article about RF issues – which discusses the use of twisted pair as well as shielding – and of more importance when and how each is effective…. http://www.audiosystemsgroup.com/RFI-Ham.pdf

    Although I know little about the in-car environment – it is clear that both twisted pair, and shielding have their place – the trick is figuring out which will give the best results for any specific type of noise….

  44. iphone 4s bumper case blog says:

    Hey man , many thanks four submitting but this publish is difficult to study when utilizing Mozilla it is doubled up.

  45. Chang Neyer says:

    This really is genuinely important post. Thanks a lot for your determination to give these sort of helpful tips here.

  46. Hulda Deuschel says:

    Beneficial tips thankfulness for posting. In truth in all posts of this site there is something to educate yourself on.

  47. fake louis says:

    You can find incredibly lots of details like this take into consideration. That’s a terrific point out talk about. I offer the thoughts above as general inspiration but clearly you’ll discover questions such as one you bring up the location that the most crucial thing will probably be in the honest excellent faith. I don?t know if guidelines have emerged about such items as that, but I am certain that your job is clearly known as a fair game. Both boys and girls have the impact of just a moment’s pleasure, for the rest of their lives.


Leave a Comment

Your email address will not be published. Required fields are marked *