AC 04S & AC 08S provides supervision of duty amplifiers and provides automatic changeover of faulty amplifiers to a standby amplifier. The AC 04S is capable of monitoring 4 duty amplifiers with automatic changeover to 1 standby amplifier while the AC 08S is capable of monitoring up to 8 Duty amplifiers with changeover to 1 standby amplifier. The standby amplifier will back-up the duty amplifiers on a first come first serve basis. The unit also provides aural and visual indication to notify users of faulty amplifier.