PURPOSE: To perform equalization free from distortion, by providing a feedback circuit in which equalizer elements equivalent to each other in terms of impedance are connected in series with a buffer amplifier connected via the equa- lizer element at the output side of a constant current driving amplfier.

CONSTITUTION: The input signal sent from a record player, etc. is fed to a constant current driving amplifier 6, and the output of the amplfier 6 is supplied to an equalizer element 7. The equalized output subjected to receive the high band attenuating function by the element 7 is converted into a low impedance by a buffer amplifier 8. While a part of the output of the amplifier 8 is fed back to the negative input side of the amplifier 6 by a negative feedback circuit 10 via an equalizer element 9. The elements 7 and 9 are set equal to each other in terms of impedance. This eliminates the transient cross modulation distortion caused by the application of excessive negative feedback. Thus the satisfactory equalization is ensured with reduced distortion.