| 摘要 |
PURPOSE:To avoid the shift in the cut-off characteristics for boost and cut, by commonly using a filter for signal paths for boost and cut, and switching the characteristics of this filter at boost and cut. CONSTITUTION:A control voltage Vc from a potentiometer 50 is fed to a switching circuit 70 to obtain a switching signal Sc different from the state in boost and cut mode. In this case, when the voltage Vc is greater than the center value V0, it is the boost mode, and when smaller than the center value V0, it is the cut mode, allowing the circuit 70 to compare the voltage Vc with the reference voltage V0. Further, this signal Sc is fed to a filter 31 to switch the time constant of the filter 31 at boost and cut. When this circuit is used for tone control, the time constant is made smaller for the boost in case of Treble and made greater for the boost in case of bue. |
