RDL FP-PA18X 18 W Mono Audio Amplifier / 8 Ohm Output / Class D / Compressor / Auto Sleep

Description

The FP-PA18X is an 18 W mono audio power amplifier designed to provide efficient, clean amplification in compact installations. It delivers 18 W RMS into an 8 Ohm load and integrates a selectable automatic sleep mode to minimize idle power consumption. The amplifier is housed in an ultra-compact all metal enclosure for reliable operation in constrained spaces.

Key features include a balanced line-level input that can accept unbalanced sources, a front-panel gain control, and an analog compressor/limiter that maximizes average output while preventing clipping. The compressor operates with multiple time constants for transparent dynamics and the unit provides LED indicators for compression activity, output active status, and power state. The high-efficiency Class D output stage minimizes heat generation while delivering voice and music material with low distortion.

Performance specifications include a frequency response of 20 Hz to 20 kHz (±1 dB at compressor threshold), THD+N below 0.5% across the audio band, and an input impedance of 10 kΩ balanced bridging or 5 kΩ unbalanced. The compressor threshold is set 3 dB below rated output and the detector circuitry identifies output activity down to milliwatt levels. Thermal and short-circuit protection are built into the output stage to protect the amplifier and connected loudspeakers.

Connectivity is handled via detachable terminal block connections for both input and output, and the gain control is positioned adjacent to the input terminal block for convenient adjustment. The output signal detector provides an open collector control output for system integration and a green OUTPUT ACTIVE LED for visual confirmation of amplified audio. The included external 24 Vdc power supply accepts 100 to 240 Vac mains and supplies the module via a grounded 24 V output.

The FP-PA18X is suited to paging, background music, small-room audio distribution, and embedded AV applications where compact size and energy efficiency are important. Its compressor/limiter allows higher average loudness without audible distortion, making it practical for voice and mixed-program material. The selectable sleep delay and near-instant wake on audio detection reduce standby energy use while ensuring responsive operation during active use.

Installation is straightforward: detachable terminal blocks simplify wiring and the single-turn gain control supports quick level alignment during commissioning. The rugged metal chassis, efficient Class D topology, and included international power supply promote long-term reliability and low operating cost. For designers seeking a small, efficient amplifier with advanced compressor behavior and system control outputs, the FP-PA18X offers a compelling solution.