AFDS2 Automatic Failure Detector and Substitutor provides continuous electronic supervision of the main and standby power amplifiers in a sound system, and substitutes the standby power amplifier should the main power amplifier’s output drop by as little as 2 dB*.The changeover is almost instantaneous with virtually no loss of signal, thereby assuring uninterrupted performance.This device is a critical, highly desirable component in systems with a dedicated emergency announcement amplifier. The AFDS2 pulses a 40 kHz frequency into the inputs of the main and standby power amplifiers and continuously analyzes their output. If the 40 kHz level from either amplifier should fall below 2 dB*, a fault alert tone will sound, indicating a failure. Front, panel-mounted LEDs indicate which (main or standby) amplifier has failed.The fault alert tone may be silenced by momentarily pressing the SILENCE button; however, the LED will stay on for the duration of the malfunction and the SILENCE button will automatically reset when the failure is corrected.