Historic Products

This section provides information and downloads for discontinued products.
These products are no longer available for new installations.
Spare parts may be available.
Contact us for more information.

< Back to category


20W 24V Amplifier with T3 Tone

20W24V web

The Pertronic 20W Amplifier (EVAC20W24V-T3) is an evacuation amplifier with integral evacuation tone and message generator and fault detection system. It is designed for use in emergency warning systems with supervised 100 Volt Line distribution systems. The amplifier delivers up to 20 Watts of audio power to the 100 Volt line.

When in standby, the 100 Volt line is connected to the BELL circuit. This allows the fire alarm panel to detect short or open circuit faults on the 100 Volt line. The BELL circuit drives a small DC current through the 100 Volt line, which must be terminated with a suitable end of line resistor. It is important to note that every speaker connected to the supervised 100 Volt Line must be specially designed for emergency warning systems, with each speaker incorporating a DC blocking capacitor.

The fault monitoring system also monitors for power supply faults, overload conditions, low power output.


  • Generates the ‘Evacuation’ tone with verbal messages as specified by ISO8201 (T3) 
  • Designed for connection to the monitored warning system output of an F4, F16e, F100 or F120 Fire Alarm Panel and is activated when the circuit voltage polarity reverses in the ‘Alarm’ state 
  • In the ‘Normal’ state, the amplifier draws practically no current (less than 0.2 µA) and appears transparent to the Fire Alarm panel 
  • The 100 Vrms line is internally connected to, and monitored by the panel’s Warning System circuit 
  • The amplifier’s 100 Vrms line is short-circuit protected and is capable of driving up to 20W (27.4 Vdc supply) into connected 100 Vrms loudspeakers

Ordering Information

Product Code




EVAC Amplifier, 20W 24V with T3 Tone



Installation Note

Enquire about this product