| 摘要 |
PURPOSE: To provide an audio amplifying device having a tone control function which can be realized at relatively low costs, in which not stepped but smooth response to a sound volume can be realized by the amplitude/frequency responding characteristics and satisfactory sound reproduction can be realized. CONSTITUTION: This is an audio amplifying device having a sound volume depending tone control function, and this device can be manufactured at low costs, and audio signals can be hardly distorted. The signal path of this amplifying device is provided with a filter device 20 and an amplifying stage 30 in which a gain can be continuously controlled. The filter device 20 decides the tone control with a low sound volume, and in this case, a low sound and a high sound can be largely amplified against a middle frequency sound. When the sound volume is increased, the amplifying stage 30 compensates the tone control. The amplifying stage 30 is provided with a linear feedback path 50 having a pole within a frequency range between the low sound and the middle frequency sound for this purpose. |
