Abstract: A sound effector for changing original sound signals generated from an electric musical instrument and picked up by a pickup element. The effector having an inductance circuit into aurally improved distinctive sounds by suitably distorting the waveform in a frequency band or original sound signals to be enhanced during amplification of the original sound signals. The sound effector includes a resonance circuit having a capacitor connected with the inductance circuit of the pickup element, an amplifier circuit composed of semiconductor elements for amplifying an output signal from the resonance circuit, a filter circuit for receiving the output signal from the amplifier circuit and for passing therethrough a signal having a predetermined frequency range, and a positive feedback circuit for positively feeding back a part of the signal passed through the filter circuit to the resonance circuit.