General
Amplifier power	120 W
Operating voltage	230 V or 24 V DC
Speaker circuits	4 switchable 100V or 70V
Inputs	5, of which 1-2 switchable Mic/Line, 3-5 Mic/Line
Input configuration	XLR and jack plug (6.3 mm)
Input processing	electronically symmetrized
Priority setting	for inputs 1 and 2
Phantom voltage	Switchable for inputs 1 and 2
Unswitched speaker outputs	100V, 70V, 8 Ohm
Daisy chaining	via AMP-IN and PRE-OUT
Tel-In	for line signals with priority
2-tone gong	remotely controlled
Media module	Suitable for installation in empty space

RCS Audio-Systems small central unit CPA-120 X is a professional amplifier for public address systems, available in units with 180/120 W power rating and 3 HE height. The device is designed for use in buildings with central public address, for example in schools, office buildings or public institutions, where reliable and flexible audio transmission is required. The CPA-120 X features 4 switchable speaker circuits, designed for either 100 V or 70 V operation, enabling flexible adaptation to existing speaker systems. The amplifier power is 120 W, with the model designation CPA-120X indicating this rated power.

Applications
This small central unit is designed for professional use in buildings with central public address. It is particularly suitable for applications requiring priority switching for emergencies, intercoms or school communication. The remote control of the 2-tone gong allows integration into existing alarm systems or school bell systems, enabling the system to be used for security and information purposes. The possibility to install audio media modules into a designated blank slot extends functionality for users requiring integrated music or message playback.

Functions and Equipment in Detail
The CPA-120 X features five inputs, with inputs 1 and 2 being switchable between microphone and line input. Both inputs support both XLR and jack connectors (6.3 mm). Inputs 3 to 5 can process both microphone signals (via XLR) and line signals (via jack). All inputs are electronically balanced, ensuring good noise rejection and signal quality. Priority and phantom power can be assigned to inputs 1 and 2, which is important for professional microphone applications. An additional Tel-In input allows feeding line signals with priority, for example from an intercom or telephone connection.

Technology Explained Simply
The amplifier can be operated with either 230 V AC mains power or 24 V DC, enabling flexible installation in various environments, for example in buildings with backup power supply or in systems based on DC. In addition to the four switchable lines, unswitched speaker outputs include a 100 V, a 70 V, and an 8 Ohm output. This allows connection of various speaker types, including those not intended to be controlled via the central switching logic. The integrated priority switching ensures that important signals, such as an emergency call or intercom, automatically take priority over other inputs.

Compatibility and Accessories
The CPA-120 X can be expanded with a CD/MP3 playback module including USB interface, or with a CD/MP3 tuner module featuring RDS tuner, CD player, MP3 player and USB interface. These modules are installed into the designated blank slot in the device and enable playback of audio media. Cascading with additional amplifiers is possible via the AMP-IN and PRE-OUT connections, allowing multiple units to be connected into a larger system. External audio sources can be fed in via the PRE-OUT input, increasing the system’s flexibility.

Mounting and Installation
The device is designed in 3 HE height and intended for installation in standard 19-inch racks. Installation typically takes place in a technical room or server room, with the power supply (230 V or 24 V) chosen according to on-site requirements. Connections are clearly labeled, and inputs support various connector types, simplifying cabling. Remote control of the gong is achieved via an external connection, which can be linked to a school bell system or intercom.

Operational Advantages
The CPA-120 X offers high operational reliability thanks to the integrated priority switching and flexible power supply. The ability to install audio media modules extends functionality without requiring additional devices. The cascading function allows system expansion without installing additional amplifiers in the same room. The unswitched outputs (100 V, 70 V, 8 Ohm) provide additional flexibility for connecting speakers not intended to be controlled via the central switching logic. Remote control of the gong is particularly useful for applications with time-controlled sequences, such as school bells.