| 摘要 |
PURPOSE:To make the size small and to reduce power compatible to each other with respect to the power amplifier for driving an electroacoustic transducer means. CONSTITUTION:In the power amplifier provided with an output amplifier 1 amplifying power of an input signal and a common amplifier 4a amplifying an input DC voltage VB to provide an output of a potential nearly the same as an output neutral point potential of the output amplifier 1 and driving a head phone 3 connected between the output amplifier 1 and the common amplifier 4a depending on the input signal, the frequency characteristic of the common amplifier 4a is selected to be a characteristic where the gain is almost flat below a predetermined frequency and decreases gradually at frequencies over the predetermined frequency, and the potential of an output terminal A is almost made constant at a predetermined frequency band including the prescribed frequency by providing a capacitor C2 at an output terminal of the common amplifier 4a. |
