SF-PA50A

RDL SF-PA50A - 50W Analog Audio Amplifier for 70V / 100V Systems

The RDL SF-PA50A is a professional Class D power amplifier that converts an analog input into a mono constant voltage output at 70V or 100V. Delivering 50W RMS, it is designed for AV installations, sound reinforcement systems, and commercial or educational environments.

An analog source can be connected via a balanced terminal block or an unbalanced stereo mini-jack, which sums both channels to mono. Gain is adjusted using a rear-panel single-turn potentiometer, supported by a dual-LED VU meter calibrated to -20 dB below maximum output.

The SF-PA50A includes an internal VCA for remote volume control via a 10 kΩ potentiometer or 0-10V DC control voltage. It is compatible with RDL remote level controls, offering rotary, pushbutton, or encoder-based control options.

The amplifier features thermal and short-circuit protection, and a current-limiting function that protects the included 24V DC power supply from overload. LED indicators display power status, mute, and analog input level. The all-metal enclosure supports free-standing, surface, or rack mounting. The unit is plenum rated (UL 2043), making it suitable for installation in air-handling spaces.

Functionality:

• converts analog input to 70V / 100V constant voltage output
• inputs: balanced (terminal block), unbalanced stereo mini-jack
• adjustable gain with dual-LED VU metering
• powered by external 24V DC supply (included)
• automatic current limiting - protects power supply
• built-in VCA for remote volume control
• compatible with RDL remote controls (potentiometer, encoder, pushbutton)
• LED indicators: power, mute, analog input level
• no special software required

Features:

• output power: 50W RMS
• constant voltage output: 70V or 100V
• Class D - high efficiency and low heat generation
• thermal and short-circuit protection
• compact metal enclosure - free-standing, surface, or rack mount
• UL 2043 compliant - suitable for plenum installations
• made in the USA - designed for continuous duty in demanding AV systems

The RDL SF-PA50A is a reliable analog amplifier solution for professional AV installations requiring high-quality sound, flexible control, and robust protection.