Power Amplifier-20 W 8 Ohm

The RDL FP-PA20 is a 20 W RMS audio power amplifier designed to drive an 8 Ω speaker. It accepts either +4 dBu balanced or -10 dBV unbalanced line-level audio and combines adjustable gain with an integral compressor for clipping control. The amplifier supports a high overall operating audio level and maximizes the available output level for its rated power.

Ideal Use Cases

This model fits audio systems that require a 20 W RMS amplifier output for an 8 Ω speaker and already provide a line-level source. Its balanced input supports +4 dBu signals, while the unbalanced input accommodates -10 dBV sources. A 20 kΩ balanced bridging input impedance and 10 kΩ unbalanced input impedance provide defined parameters for matching connected source equipment. Detachable terminal-block connections suit installations that call for secured wiring with the convenience of a removable connector.

Why Choose This Model

The FP-PA20 combines its rated amplifier output with an integral audio compressor that helps control clipping. The compressor threshold is set 6 dB below rated output and uses automatically adjusting attack and release. A red PEAK LED indicates compressor activity, providing a visible reference when the circuit is operating, while a green LED confirms that power is on. Single-turn audio-taper gain adjustment allows the installed level to be set directly at the amplifier.

Installation and Integration

The amplifier measures 2.3 inches high, 3.25 inches wide, and 6 inches long, equivalent to 5.85 by 8.26 by 15.3 cm. Audio input and output wiring connect through a detachable terminal block. The FP-PA20 requires ground-referenced 24 Vdc power at 1650 mA for continuous RMS power output or 1000 mA for normal uncompressed audio. The recommended power supplies, which are not included, are the PS-24V3A or PS-24KS for the USA and the PS-24V3 or PS-24KX for international use. The specified ambient operating range is 0° C to 30° C maximum, with 20° C recommended.

Performance Highlights

Rated output is 20 W RMS into 8 Ω. Frequency response extends from 35 Hz to 50 kHz within ±1.5 dB. THD+N is specified at less than 0.1% at 1 kHz and less than 0.5% from 35 Hz to 20 kHz, measured at the compressor threshold level corresponding to 4 W RMS output power. Noise is specified below -80 dB relative to 20 W RMS, and common-mode rejection is greater than 55 dB from 50 Hz to 120 Hz. Minimum input levels required to cross the compressor threshold are -26 dBu balanced and -28 dBV unbalanced. Maximum input levels are +23 dBu balanced and +15 dBV unbalanced.

What Makes It Different

The FP-PA20 brings together 20 W RMS output, balanced and unbalanced line-level compatibility, adjustable gain, and automatic compression in one model. Its compressor is integrated specifically to control clipping while allowing a high overall operating audio level. The combination of a wide specified frequency response, low published distortion figures, defined noise performance, and visible compressor activity distinguishes it from an amplifier described only by its power rating. RDL also identifies its audio quality as superior to standard amplifiers.

Final Assessment

The RDL FP-PA20 is a focused choice for driving an 8 Ω speaker from balanced or unbalanced line-level audio. Its detachable terminal block, gain control, power and peak indicators, and automatic compressor provide the essential controls and status information needed for integration. With 20 W RMS output and clearly specified audio measurements, it offers a documented performance profile in a compact enclosure. A compatible 24 Vdc power supply must be selected separately.