| 摘要 |
PURPOSE:To satisfy resisting ability to an interference signal and to reduce hum voltage by connecting a low pass filter consisting of a resistor and capacitors to the non-inversion input of the initial differential amplifier in an equalizer amplifier proper to a moving magnet type pickup in an audio amplifier or the like and connecting a capacitor between both the inputs of the differential amplifier. CONSTITUTION:The low pass filter consisting of the resistor 8 and the capacitors 7, 9 is connected to the non-inversion input of the initial differential amplifier 1 in the equalizer amplifier, so that the input circuit of the equalizer amplifier is simplified. In addition, an effect for attenuating an interference signal due to the high impedance characteristics of high frequency which is ordinally obtained by the use of a coil can be attained by selecting the capacity of the capacitor 2 connected between the inversion input and non-inversion input of the amplifier 1. |
