In the tangle of wires connecting your audiovisual system, the most familiar are the traditional RCA cables -- with their red- and white-labeled audio plugs and yellow-labeled video plugs. They're physically identical to the red-yellow-green connectors used for component video, and the non-optical variety of digital audio cable, so it's only natural to wonder whether you could use a spare audio cable for video. Although this can be a useful stopgap, as it may save you a trip to the store, there are some compromises involved.
Standard audio/video cables using RCA connections date back to the Depression, when the RCA company and its RCA Victor subsidiary were dominant players in the phonograph and radio business. Radios were the home theater systems of the day, with powerful, high-quality speakers. RCA connectors were created so consumers could connect their record players to the radio, enjoying higher-fidelity audio quality. The connector consists of a center pin and an outer, cylindrical shield, soldered to a coaxial cable made up of a center signal wire surrounded by insulation and a braided copper shield. Although these cables are still in widespread use, the 80-year-old technology has its limitations.
A number of factors determine how well an RCA cable will transmit its signal. The larger the diameter of the central wire, the less a signal will deteriorate as it passes through. In high-end cables, they're typically 0.65mm or larger, while low-end cables may be half that. Oxygen-free copper, typically abbreviated to OFC, also reduces signal loss and distortion. Good cables should be shielded with both foil and a heavy copper braid, and should terminate in heavy-duty connectors with gold plating for corrosion resistance and good connectivity. Low-end RCA audio cables have relatively poor specs. Higher-quality cables are more closely comparable to video cables in their design and construction.
Using Audio Cables
If you're hooking up an elderly VCR or DVD to a low-end TV, the signal quality will be low -- and substituting an audio cable won't matter. If you're connecting higher-quality components, use only a good-quality audio cable with a heavy, OFC core and lots of shielding. Bear in mind, the RCA A/V inputs on your TV are limited to 480p resolution. The only way to get high-definition video using RCA cables is by connecting three high-end audio cables to the red, green and blue component video inputs. If you don't have three top-of-the-line audio cables, you may as well run to the store and buy the correct cable.
Making the Connections
If you have a surplus RCA audio cable of appropriate quality, use colored electrical tape or a twist-tie to identify it in the tangle behind your system. Plug one end into the yellow Video Out on your DVD or other signal source, and the other into the yellow Video In on your TV. If your cable has two connections, tape or bag the other to prevent it from making any unintended contacts between components. Follow the same procedure if you're connecting through the red/green/blue component video inputs, labeling each separately. Remember, this only transfers video and you'll still need another cable for left and right audio connections.
- Hemera Technologies/AbleStock.com/Getty Images