The Adastra RS Series is a range of Class-D 100V line slave amplifiers designed to expand commercial sound installations, available in four output options: 120W (1U), 240W (1U), 360W (2U), and 480W (2U).

Slave amplifiers like the RS Series are used alongside a mixer-amplifier to increase system capacity — adding more speakers or extending coverage into additional areas without replacing the existing head unit. The RS Series accepts a standard line-level signal from any mixer or compatible mixer-amplifier, and multiple units can be cascaded via the slave line output to build larger systems as requirements grow.

A particularly useful feature is the 100V signal input, which allows the RS Series to be connected directly to an existing 100V speaker feed rather than a dedicated line-level output. This makes it straightforward to extend a 100V installation using standard double-insulated cable over long cable runs, without requiring a separate signal cable back to the source.

Speaker output is 100V line or low-impedance (stable down to 2 Ohms on the RS121 and RS241), with all connections made via screw terminals for a secure, permanent installation. A 24V mute terminal is provided for integration with alarm or security panels, allowing the output to be silenced automatically when triggered.

• Class-D Efficiency: Lightweight and energy-efficient Class-D amplifier design reduces heat output and running costs, making it well suited to permanent commercial installations.
• Flexible Signal Inputs: Accepts line-level audio via RCA sockets or Euroblock screw terminals, plus a dedicated 100V input for extending existing speaker runs directly.
• Cascadable Slave Output: Line-level slave output allows multiple RS units to be daisy-chained, giving straightforward scalability for growing installations.
• 100V or Low-Impedance Output: Switchable between 100V line and low-impedance operation (down to 2 Ohms on 120W and 240W variants), accommodating different speaker configurations.
• 24V Alarm Mute: Screw-terminal mute contacts allow integration with a security or alert panel to silence the output during alarm activation.
• 19" Rack Mountable: 1U format for the 120W and 240W variants, 2U for the 360W and 480W variants — supplied with rack or surface mounting ears as standard.

Specifications

• Brand: Adastra
• Model: RS121 / RS241 / RS360 / RS480
• Output Power (RMS): 120 W / 240 W / 360 W / 480 W (variant dependent)
• Rack Format: 1U (120W, 240W) / 2U (360W, 480W)
• Speaker Outputs: 100V or 2 Ohms min. (screw terminals)
• Signal Input: Slave line in via RCA or Euroblock screw terminal; 100V in via screw terminal
• Signal Output: Slave line out via RCA or Euroblock screw terminal
• Controls: Master volume
• Mute: 24V alarm contacts (screw terminal)
• Frequency Response: 90 Hz – 20 kHz (100V) / 17 Hz – 90 kHz (2 Ohms)
• THD: <1.0%
• Mains Power Supply: 175–264 Vac, 50 Hz (IEC)
• Fuse: T1A
• Dimensions (W × H × D): 433.0 × 44.0 × 267.0 mm (120W variant)
• Weight: 4.8 kg (120W variant)

What You Get

• 1 x Amplifier
• 1 x Power Lead
• 2 x Rack Mounting Ears