Usage of the HMM-Based Speech Synthesis for Intelligent Arabic Voice.

A preamplifier circuit for enhancing sound generated by a musical instrument such as a guitar and which is converted into electrical signals includes an input, a passive high impedance input network connected to the input, a first preamplifier connected to the passive input network for non-distortion amplification of the electrical signals in a first mode of operation and for saturation distortion amplification of said electrical signals in a second mode of operation. A switch circuit enables switching between the first and second modes of operation. An overdrive amplifier bridges across the passive input network in response to the switch circuit for overdriving the first preamplifier thereby to cause saturation distortion amplification of the electrical signals. A shunt network may be switched across the output terminal to equalize output amplitude of the preamplifier circuit between the first and second modes of operation.