RCA cable is most commonly used to transfer analog (non-digital) audio signals between electronic components. The familiar cable is two-tailed with one red and one white tail on each end, though some cables might substitute black for white. Many RCA cables have a third yellow tail for delivering a composite video signal. The cable connector is a male push-in, with a thick central pin surrounded by a thin, rounded collar or crown. RCA cabling can also deliver component video signals.
The tails of an RCA cable are color-coded to correspond to the proper input or output jack on electronic equipment. Red tails or black tails connect to the right channel inputs/outputs, while white tails are used for left channels. In reality both wires are exactly the same, so switching colors makes no difference, but it is important that the same color be used for the same channel at each end of the cable. Since “red” and “right” both start with an “r,” it’s an easy way to remember how to connect the cables in a consistent manner, even on components without color-coding.
Much emphasis has been placed on the types of cables used to connect components and the ability to deliver signals without introducing interference. In some cases companies charge enormous amounts of money for cables that are supposed to deliver superior performance. Some of these cables have large, intricately designed molded heads and flashy packaging that necessarily figure into cost but not necessarily performance.
One generally accepted myth is that gold tips or connectors are always superior to silver. While gold does not conduct sound any better, it is non-corrosive and more malleable than silver, which could be an argument for buying gold-tipped plugs for applications where the plugs will be left in place. If the cables will be used in a patch bay where they will be plugged and unplugged often, silver tips might actually be a better choice than soft gold plating that can wear away.
A typical run of up to 10 feet (~3m) does not require an expensive audio RCA cable, though the cheapest possible cable — the type included with many electronic components as a freebie — might not be the best choice. Even still, the average person probably wouldn’t notice a difference between this RCA cable and another. Speaker wire gauge and type has a greater ability to make a discernible difference in audio, all else being equal, than the RCA cable. Choosing a modestly priced cable should do the trick.
RCA cable is also used for transferring component video. The three tails are color-coded as green, blue and red to correspond to female jacks on video equipment. Component video breaks the video signal up into three spectrums to deliver truer color than composite video, which travels over a single wire.
Some argue that since all RCA cable is rated at 75-ohms it can be used for any RCA application. While it’s true that any RCA cable will do in a pinch, even a red, white and yellow-tailed cable, this isn’t ideal and probably won’t deliver a clean signal. The problem is that most RCA cable is not a true 75-ohms, the specification required by video.
RCA cable started out as an audio-only cable, requiring 50-ohms. Audio operates at comparatively low frequencies up to about 20,000 Hertz, but video covers a much higher frequency range, up to 35-Megahertz for HDTV. This makes it more susceptible to factors like mismatched impedance that can create interference and signal degradation. In this application shielding and cable construction become more important to avoid affects like ghosting and general loss of quality.
For these reasons it’s best to buy an RCA cable specifically made for component connections that comes as close to a true 75-ohms as possible. Unfortunately, marketing sometimes trumps facts, and price does not always guarantee quality. The most expensive cables are likely over-selling themselves with hype, while the cheapest component cable might be no better than the average RCA cable at an inflated price. Look for brand advice on AV forums and related websites. If you shop at a local retailer, avoid chains that carry a single, overpriced product line.