Biasing an amplifier is a method of establishing proper operating conditions inside the amplifier output stage.
It must remain constant, no matter how hard and hot the amplifier is run. A temperature variation (ambient temperature or amount of power that is supplied to the loudspeaker) will modify the characteristics of the amplifier circuit. In order to achieve an unconditionally steady bias, CH Precision developed a patent pending electronic system (the ExactBias circuit) that automatically and linearly regulates the bias of the amplifier by monitoring in real-time the temperature right inside the power transistors and act accordingly.
This ExactBias circuit is used in all CH amplifiers.