PURPOSE: To avoid the heat generation and thus to increase the damping factor by using the potentiometer and the buffer amplifier for the fader controller which distributes the signals to two speakers from the power amplifier.

CONSTITUTION: Both output ends O1 and O2 of power amplifier Apw are connected across of potentiometer VR, and the sliding terminal of the VR is connected to the input terminal of buffer amplifier Abf. Furthermore, the output terminal of Abf is connected in common to one terminal each of speakers S1 and S2, and the other terminals of the speakers are connected across the VR. In fader controller FC consisting of the VR and amplifier Abf, the signal current has not to be flown to the VR to drive the speaker. As a result, the power loss never occurs at the VR, at the same time avoiding impairment of the frequency characteristics.