Abstract: A preamplifier for audio frequecy electrical signals generated by a musical instrument such a guitar having distortion characteristics simulating those of a vacuum tube amplifier. A solid state amplifier has an input for receiving electrical signals generated by the musical instrument and has an output for providing an output signal. Circuitry asymmetrically clips the output signal to provide as the output signal a nonlinear asymmetrically clipped signal having harmonic content which varies as a function of the amplitude and duration of the received electrical signals. The clipped signal has musically desirable harmonic overtones and produces different tonal responses simulating the characteristics of an overdriven vacuum tube amplifier.

Abstract: A first amplifier stage receives electrical signals generated by a musical instrument and provides an output signal. A second amplifier stage is driven by the output signal from the first amplifier stage as switch selectively connects an attenuator to the first amplifier stage to attenuate the output signal thereof and selectively connects a gain modifying circuit to the first stage. In a first mode, the attenuator is connected to the first amplifier stage and the gain modifying circuit is disconnected from the first amplifier stage. As a result, an output signal from the first amplifier stage has a level which drives the second amplifier stage to provide a substantially linear output signal therefrom. In a second mode, the attenuator is disconnected from the first amplifier stage and the gain modifying circuit is connected to the first amplifier stage.