RDL SF-MA100A 100W Mono Mixer-Amplifier 70V / 100V 3-Input Format-A Loop-Out

Description

The SF-MA100A is a 100 watt constant-voltage mono mixer-amplifier that accepts three Format-A audio inputs and provides a 70 V or 100 V output. It mixes the three Format-A pairs locally or via remote VCA control and passes Format-A signal and power pairs through to a loop-out jack. The unit is engineered for continuous duty in demanding installations and includes a 48 Vdc module power supply.

Key features include three selectable operating modes, internal VCAs for noise-free level control, a selectable audio compressor that adds up to 15 dB of headroom, and a dual-LED VU meter for installer metering. The amplifier uses a high-efficiency Class D output stage to minimize heat and improve reliability. Front and rear indicators provide Ready, Overload Shutdown and Format-A power status feedback.

Performance specifications provide useful headroom and clean output: 100 W RMS constant-voltage output, frequency response of +0/-3 dB from 50 Hz to 20 kHz, THD+N under 1% at full power, and noise floor below -85 dB at maximum power. The compressor features automatic attack and release timing for transparent dynamic control. The input CMRR exceeds 80 dB in the critical low-frequency band to reduce hum and interference.

Connectivity is centered on the RJ45 Format-A interface which carries three signal pairs and module power. The LOOP OUT RJ45 jack provides pass-through to additional Format-A receivers or amplifiers. Remote control options include RDL D*-RLC10KM master level controls or D*-RC3 three-channel wall remotes via the RJ45 VCA control, or direct 10 kOhm potentiometer or 0-10 Vdc control voltages.

The SF-MA100A is suited to paging, background music and distributed audio systems in schools, retail, houses of worship and corporate environments where constant-voltage speaker lines are used. It mixes multiple sources and can be controlled locally or remotely to fit different operational workflows. Loop-through Format-A outputs make it simple to expand multi-zone systems by daisy-chaining additional amplifiers.

Installation is straightforward with a compact all-metal enclosure that supports surface or rack mounting and an included IEC power supply providing 48 Vdc to the module. The unit is plenum rated to UL 2043 and includes thermal and short-circuit protection for long-term reliability. Installer-adjustable rear-panel pots set input gain and the VCA range for remote control, simplifying commissioning and maintenance.