A power amplifier is a type of amplifier that supplies power to one or more loudspeakers. It does not have the additional features and connections often found on a home theater receiver, such as a radio, input source switching, and audio/video (AV) processing. The only control you typically find on a power amplifier (other than a power switch) is a primary gain control, which is analogous to volume.

Power amplifiers come in a variety of channel configurations, from one channel (called a monoblock) to two (stereo) channels. For surround applications, power amplifiers may have five, seven, or more channels.

When nine channels are needed, either seven- or two-channel power amplifiers can be used. When eleven channels are needed, a seven-channel amplifier is combined with two two-channel amplifiers. A monoblock amplifier can be used for each channel, which requires many amplifiers.

To send audio signals to a power amplifier, a separate preamplifier or AV preamplifier/processor is required.