Choose a microphone amplifier with enough output for the connected speaker load, allowing appropriate headroom, and match its output type to the system, such as low-impedance, 70V, or 100V speakers. Select a single-channel unit for one audio zone, while two- or multi-channel models support separate zones, multiple speaker groups, or independent audio sources.

Look for microphone amplifiers with balanced and unbalanced microphone inputs, such as XLR or terminal connections, plus phantom power when the installation uses condenser microphones. Source connections may include balanced or unbalanced line inputs, RCA, mini stereo, Bluetooth, or network audio, while priority inputs and ducking can help lower background music when paging or speech begins.

Microphone amplifiers can use priority inputs to lower background music or other program audio when a paging microphone becomes active, helping speech remain clear. Models with emergency inputs can mute other sources for an alert, while microphone processing such as ducking, gating, compression, and de-essing supports controlled announcements.

Low-impedance microphone amplifiers drive speakers connected directly at low impedance, such as four-, eight-, or 16-ohm systems, and are commonly used for smaller speaker setups or dedicated zones. Constant-voltage microphone amplifiers use distributed-audio outputs, such as 70V or 100V, to support multiple speakers over longer cable runs, making them well suited for paging, background music, and commercial installations.