Preamplification system for an acoustic guitar or other music instrument with vibrating parts

Sound detection system of a musical instrument with vibrating parts, comprising at least a pair of sensors and preamplification unit for processing the signal output from the two sensors along respective channels, wherein

• at least one of the pair of sensors is a piezoelectric transducer and the other one of the pair of sensors is a transducer of another type,
• said preamplification unit comprises, for each one of the channels, an input stage, comprising an amplifier circuit and an equalization circuit, and an output stage comprising at least a weighted adder circuit and at least two volume controls with arbitrary logarithmic response curve, and wherein
• at least the input stage for the channel of said piezoelectric transducer is a charge amplifier circuit and at least one of the other input stages can be configured both as a charge amplifier and as non-inverting amplifier with high input impedance, and wherein
• said equalization circuit comprises an RC circuit, and
• wherein the output stage has an adder section of the at least one pair of signal channels, defined providing a resistive trimmer (P2, P4, P6) in series to each input network (RC) of each channel to an adder amplifier (U3), so as to obtain a different excursion of the maximum gain value for each channel of said adder amplifier.