Network to 50 W Mono Audio Amplifier-70 V or 100 V-Dante-Includes North American Power Cord

Ideal Use Cases

The RDL SF-NP50A is designed for installations that need to convert one Dante network audio channel into a mono constant-voltage speaker output. Its 50 W RMS amplifier can be configured for either 70 V or 100 V operation, making it suitable for distributed audio systems that require network-based signal delivery and constant-voltage amplification from a compact module.

It also supports applications that combine network and analog sources. The analog section accepts a balanced mono signal through a terminal block or an unbalanced stereo signal through a mini-jack, with the left and right channels summed to mono. Switch-selectable priority and automatic ducking allow either the Dante network input or analog input to control ducking and muting behavior.

Why Choose This Model

The SF-NP50A combines Dante reception, analog input flexibility, source-priority control, and a 50 W constant-voltage amplifier in one unit. Supported Dante sample rates include 44.1, 48, 88.2, and 96 kHz, with 48 kHz used as the default. Digital audio is supported at 24-bit depth over a 100 Mbps Ethernet connection.

A network input level of 0 dBFS produces the rated 50 W output. The unit also provides a balanced +4 dBu line output from the network audio source at -20 dBFS, allowing the received Dante signal to feed another balanced audio device. High-efficiency Class D operation is complemented by thermal protection, short-circuit protection, overload indication, and automatic supply-current limiting intended to protect against power-supply shutdown.

Installation and Integration

The network connection uses an RJ45 port with link and speed indicators. Analog audio can be connected through the balanced terminal-block input or the unbalanced stereo mini-jack. A detachable terminal block provides 0 to 10 Vdc VCA control and compatibility with RDL VCA wall controls. External level adjustment can also be performed with a 10 kΩ potentiometer.

Module setup does not require special software. A single-turn audio-taper gain control works with a dual-LED VU meter calibrated to 20 dB below full output power. Automatic ducking is configured with a rear-panel adjustable signal threshold and corresponding LED indicator. Ducking attenuation is switch-selectable between a nominal 25 dB reduction and off, while the nominal release delay is four seconds.

The amplifier is plenum rated to the UL 2043 standard. It measures 1.7 inches high by 5.83 inches wide by 6.45 inches deep. The specified operating environment is 0 to 40 degrees C maximum, with 20 degrees C recommended. An included 100 to 240 Vac, 50-60 Hz power supply delivers 24 Vdc to the module, and the product configuration includes a North American power cord.

Performance Highlights

The amplifier delivers 50 W RMS into a selectable 70 V or 100 V output. Frequency response is rated at +/- 0.3 dB from 20 Hz to 10 kHz and +/- 2 dB from 20 Hz to 20 kHz. THD+N is specified at less than 1 percent at 1 kHz, while common-mode rejection is greater than 60 dB from 50 Hz to 120 Hz.

The balanced input has an impedance greater than 10 kΩ and a nominal level of +4 dBu, with adjustment from a -10 dBu minimum reference to a +25 dBu maximum before clipping. The unbalanced input impedance is greater than 5 kΩ. Its input range extends from -25 dBV at 20 dB below full output power to +10 dBV maximum before clipping, with a stated nominal level of 10 dBV.

What Makes It Different

Unlike a standalone constant-voltage amplifier, the SF-NP50A directly receives one channel of Dante audio while retaining a separate analog input path. Its switch-selectable network or analog priority, automatic threshold-based actuation, and selectable ducking behavior provide source management inside the amplifier module.

Eight indicators communicate operating status across the front and rear panels. These include network sync, amplifier mute, overload protection, Ethernet link and speed, a dual-LED VU meter, and ducking threshold indication. This visual feedback supports setup and operating checks without requiring dedicated module-configuration software.

Final Assessment

The RDL SF-NP50A is a focused network-to-amplifier solution for a mono 70 V or 100 V audio system. It brings together 50 W RMS output, four selectable Dante sample rates, balanced and unbalanced analog connectivity, automatic ducking, remote VCA control, a balanced network-audio line output, and multiple protection functions. The included universal-input power supply and North American power cord complete the specified package.