RDL SF-PA50A 50 Mono Audio Amplifier, Analog Input to 70V or 100V

Designed for dependable distributed-audio and paging applications, the Radio Design Labs SF-PA50A is a pro-grade mono amplifier that delivers 50W of constant-voltage power to 70V or 100V speaker lines. Ideal for security, surveillance, and facility monitoring systems, this compact Class D amplifier provides high-efficiency performance with minimal heat generation—perfect for continuous-duty installations.

The SF-PA50A accepts a balanced mono input or an unbalanced mini-jack (sums L/R), and includes a rear-panel gain control with dual-LED VU metering for fast system tuning. An internal VCA and detachable terminal block enable smooth remote level control via a 10 kΩ potentiometer or 0–10 V control, giving installers flexible zoning and user-volume options. Safety features such as thermal and short-circuit protection plus intelligent current limiting protect the power supply during overloads and feedback events.

Housed in a durable metal enclosure and plenum-rated to UL 2043, this Radio Design Labs amplifier is built for commercial AV, retail paging, education, and security monitoring environments. Upgrade your paging or surveillance audio infrastructure with the SF-PA50A—contact sales or add to your system design for reliable, long-term performance.

• Delivers reliable 50W constant-voltage audio to drive 70V or 100V speaker lines for clear paging and distributed audio
• Class D efficiency minimizes heat and power draw, reducing rack cooling and operating costs in continuous-use installations
• Integrated VCA with remote control option provides smooth, noise-free level control for zones, monitoring, or security paging systems
• Built-in thermal and short-circuit protection with current limiting preserves system uptime and prevents power-supply shutdown during faults
• Multiple input options (balanced mono + summed mini-jack) and plenum-rated construction simplify installation in AV, surveillance, and monitoring environments