Input selector, a signal processing circuit, an audio signal processing circuit

The present invention provides a flexibility to adapt various input selector signal input form, a signal processing circuit, an audio system, an audio signal processing circuit, a tone control circuit. A first selector (SELl) receiving a second input signal (SIG2) and a second reference voltage (Vref2), wherein the selected one. A first buffer (BUF1) receiving the output signal of the first selector (SELl), and outputs to the other ends of the first resistor (R1) and a third resistor (R3) is. A second selector (SEL2 is) receiving a first input signal (SIG1) and the third input signal (SIG3), and select one. Output signal of a fourth selector (SEL4) is input to the operational amplifier (AMP1 is) output signal, and a second selector (SEL2 is) (S2) of a corresponding signal (S2 '), and a second input signal (SIG2) corresponding signal (S3), wherein the selected one.