Connecting a separate amplifier to a home theatre or hi-fi receiver allows you to boost the system's power to ensure that the speakers receive the ideal amount they need to sound their best. In addition, reducing the workload of the receiver's integrated amplifier generally improves system performance. Learn more about audio amplifiers and the way to pair an audio amplifier with a receiver, in order to enjoy your audio system even more.
Matching an Audio Amplifier to Receiver Channels and Connections
Surround sound or AV receivers feature multiple channels for connecting multiple speakers. A 5.1-channel receiver outputs to five channels or speakers and a subwoofer, and a 7.1-channel receiver outputs to seven channels and a subwoofer. The low frequency effects (LFE) channel, the '.1' in the description, is an unamplified 'line-level' signal, which the subwoofer amplifies. A stereo receiver has two channels for connecting two speakers and rarely supports video or digital inputs. This type of audio system is best suited to small rooms and home audio systems. Receivers usually contain Class AB or Class D amplifiers, and adding a discrete amplifier unit can improve sound quality. The amplifier you choose should have the same number of channels the receiver has. In addition, the receiver should have adequate 'pre-out' or 'line-out' connections to accommodate the signals for all your speakers.
Connecting an Audio Amplifier with Receiver's Pre-Out or Line-Out Connections
Line level signals have lower voltages than speaker level outputs do, so you cannot connect the speaker outputs of a receiver directly to the line level inputs of an amplifier. Most modern receivers come with pre-out or line out connections. Connecting an amplifier to these connections reduces the workload of the receiver's integrated amplifier, which may improve performance. This effectively turns the receiver into a pre-amplifier or processor. If your receiver does not have line out connections, you can add a high-to-low voltage adapter to the system.
Choosing an Audio Amplifier
An audio amplifier forms part of an audio system and must match all the components in the system. Consider the specifications of the receiver as pre-amplifier or processor and the speakers when making your selection. The number of speakers determines the number of channels required; each speaker uses a separate channel. Pair a 5.1 receiver with a 5.1 amplifier and a 7.1 receiver with a 7.1 amplifier. The subwoofer requires its own mono channel. In addition, match the speaker power rating to the amplifier output to prevent clipping, distortion, and speaker damage. Note the power per channel and the number of channels the amplifier can drive at the same time. Manufacturers tend to specify the total amplifier power, but speakers come rated as power per channel. Matching the receiver, amplifier, and speakers produces clear sound and high fidelity sound reproduction.