3.5 Watt Decora Audio Amplifier

Ideal Use Cases

The RDL D-PA3 is designed for installations that need a compact, wall-mounted amplifier with convenient access to two audio sources. Its rear-panel balanced input accommodates a permanently connected source, while the front-panel mini-jack provides an accessible connection for another device. Automatic input switching and solid-state source selection make it suitable where users need to change sources without operating a separate selector.

The amplifier drives a 4- or 8-ohm speaker and supports both voice and music program material. Its compact dimensions make it particularly useful when available wall space and equipment depth are limited.

Why Choose This Model

The D-PA3 combines two input paths, automatic switching, amplification, and local gain adjustment in one all-metal unit. The front-panel single-turn audio-taper control provides direct gain adjustment at the installed location. Behind the panel, the speaker output uses a detachable terminal block, allowing the output wiring to be connected without relying on a front-facing cable.

Output power is matched to common 4- and 8-ohm speaker loads. The amplifier supplies up to 3.5 W RMS into 8 ohms and up to 6.5 W RMS into 4 ohms. High-efficiency Class D operation, thermal protection, and short-circuit protection address efficiency and common amplifier fault conditions.

Installation and Integration

The D-PA3 measures 4.13 inches high, 1.7 inches wide, and 2.05 inches deep, or 10.49 by 4.32 by 5.21 centimeters. Its wall-mounted format and ultra-compact construction allow the amplifier, input access, gain control, and speaker connection to be integrated at a single location.

The unit requires 24 Vdc. Current demand is specified at 30 mA while idle, 55 mA at one-eighth power with normal voice or music, and 225 mA when delivering 3.5 W into an 8-ohm load. Recommended power supplies are the PS-24AS for the USA and PS-24AX for international applications. The specified ambient operating range is 0°C to 40°C maximum, with 20°C recommended.

Performance Highlights

The amplifier covers a frequency response of 20 Hz to 20 kHz within ±1 dB. THD+N is specified below 0.1% at 1 kHz and 1 W. Noise is below -80 dB relative to 1 W RMS when using the balanced input and below -70 dB when using the mini-jack input. Common-mode rejection is greater than 50 dB from 50 Hz to 120 Hz.

The two inputs have a 20 kΩ balanced or unbalanced bridging impedance. Nominal input levels are +4 dBu for the balanced, low-sensitivity input and -15 dBV for the unbalanced, high-sensitivity input. Maximum input levels are +22 dBu at low sensitivity and +4 dBu at high sensitivity, giving the amplifier defined operating levels for both input paths.

What Makes It Different

The D-PA3 places a balanced input on the rear panel and a mini-jack input on the front instead of requiring both sources to share the same connection area. Automatic switching coordinates these inputs, while solid-state switching handles source selection. This arrangement combines a concealed installed connection with an immediately accessible front input.

Its rear speaker output, detachable terminal block, and front gain adjustment divide installer connections from user-facing controls. The result is a focused amplifier layout with no unnecessary front-panel connections beyond the mini-jack and gain control. Class D circuitry and all-metal construction complete the compact design.

Final Assessment

The RDL D-PA3 is a purpose-built Decora audio amplifier for wall-mounted systems requiring two automatically switched inputs and one 4- or 8-ohm speaker output. Its 3.5 W and 6.5 W output ratings, full-range frequency response, front gain control, detachable speaker terminal, compact metal construction, and integrated protection provide a clearly defined solution for localized voice or music amplification.