Car audio amplifiers are audio power amplifiers that magnify a very low voltage signal to drive car speakers with higher power than a standard car stereo can provide. Unlike home audio power amplifiers and AV receivers, they require additional circuitry to avoid picking up and amplifying noise signals which are extremely common in vehicle electrical systems.
High-power car amplifiers use a switched mode power supply (SMPS) which steps up the 12V battery supply voltage and creates both positive and negative supply voltages for the output stages. Additionally many work with lower speaker impedances than home stereo amplifiers as this is necessary to create high power output (higher current, in Amperes) with the limited supply voltage available.
Various models feature different independent sound channel options with some dedicated to driving car subwoofers. Multi-channel car amplifiers are designed to be flexible for a wide variety of vehicle audio installation possibilities.