RCA cables are analogue audio cables commonly used to connect hi-fi components such as amplifiers, CD players, DACs, network streamers, turntables and other audio equipment. They are one of the most recognisable types of connection in home audio and remain widely used on modern hi-fi equipment.
A stereo RCA cable normally has two connectors at each end, with one carrying the left audio channel and the other carrying the right. The right channel is usually identified by a red connector, while the left is normally white or black. Each connector has a central pin that carries the audio signal and an outer connection that acts as the ground.
RCA cables are commonly used to connect the analogue output of a source component to an amplifier. For example, a CD player, DAC or network streamer may have a pair of RCA outputs that connect to the corresponding RCA inputs on an integrated amplifier or preamplifier. RCA connections can also be found between preamplifiers and power amplifiers and are frequently used with subwoofers.
Turntables can also use RCA cables, although the signal produced by a phono cartridge is much lower than the standard line-level signal produced by most other audio components. Depending on the turntable and amplifier, a separate phono stage may therefore be required between the turntable and amplifier.
Although RCA connectors are strongly associated with analogue audio, the same physical type of connector can also be used for digital coaxial connections. A conventional stereo analogue connection uses two RCA cables for the left and right channels, while an S/PDIF digital coaxial connection normally uses a single cable to carry a digital audio signal.
The quality and construction of an RCA cable can affect its durability, resistance to interference and reliability. Good shielding can help protect the audio signal from electrical and radio-frequency interference, while well-made connectors provide a secure connection between components. Cable length can also be important, particularly when dealing with the low-level signal produced by a turntable cartridge.
Despite the introduction of newer connections such as USB, HDMI, optical digital and balanced XLR, RCA remains an important part of hi-fi. Its simplicity, widespread compatibility and ability to carry analogue stereo audio mean RCA cables continue to be used with everything from affordable stereo systems to high-end audio equipment.