What is IOC?
IOC stands for Input Output Comparator. This circuit compares the output signal of the amplifier with the input signal. If there is any difference other than gain, then it is considered distortion and the indicator comes on. The LED indicator will come on whenever there is distortion of 0.05% or more. This is a dynamic Proof of Performance of the amplifiers functionality. Anytime you experience distortion in your system you can view the IOC indicators. If they are not lit then you know that the amplifier is not at fault. If the IOC indicators are on, then the amplifier is in distortion.