Balanced distortion for musical instrument

An audio distortion circuit to provide balanced distortion in a musical instrument and to emulate the sound of a tube amplifier when overdriven, the audio distortion circuit comprising:

• an input stage amplifier, with balanced outputs that are opposite in polarity, adapted to receive an input audio signal, remain linear, and maintain balanced outputs, and adapted to split the input audio signal into two parallel signal paths, an inverting, negative path and a non-inverting, positive path;
• an inverting, negative path balanced distortion circuit, comprising a first P channel MOSFET, a first N channel MOSFET, and a first diode, and following the inverting, negative path and adapted to receive an inverting, negative path input, wherein an output negative path exited from the inverting, negative path balanced distortion circuit comprises a first full waveform;
• a non-inverting, positive path balanced distortion circuit, comprising a second P channel MOSFET, a second N channel MOSFET, and a second diode, following the non-inverting, positive path, and parallel to the inverting, negative path balanced distortion circuit, and adapted to receive a non-inverting, positive path input, wherein an output positive path exited from the non-inverting, positive path balanced distortion circuit comprises a second full waveform;
• wherein the first diode and the second diode each is adapted to be switched selectively into the circuit or switched selectively out of the circuit to provide a variation in tone;
• wherein a transfer characteristic of each of the P channel MOSFETs is not required to be exactly equal and opposite, complimentarily matched, to a transfer characteristic of the N channel MOSFET;
• an output stage amplifier with differential input following the inverting, negative path balanced distortion circuit and the non-inverting, positive path balanced distortion circuit, wherein the output stage amplifier with differential input is adapted to combine a pair of differential inputs, one the output negative path exited from the inverting, negative path balanced distortion circuit, the first full waveform, and two the output positive path exited from the non-inverting, positive path balanced distortion circuit, the second full waveform, to produce an output audio signal;
• wherein the audio distortion circuit is adapted to cancel incoming asymmetries in the output stage amplifier with differential input from the combined pair of differential inputs and produce the output audio signal as symmetric;
• and
• wherein the audio distortion circuit is adapted to distort, clip, and limit, selectively by a user, the input audio signal.

A method to provide balanced distortion in a musical instrument and to emulate the sound of a tube amplifier when overdriven, the method comprising:

• receiving an audio input signal at an input stage adapted to receive an input audio signal, while maintaining linearity and maintaining balanced outputs;
• splitting the input audio signal into two parallel signal paths, an inverting, negative path and a non-inverting, positive path;
• passing a first signal through an inverting, negative path balanced distortion circuit following the inverting, negative path and adapted to receive an inverting, negative path input, wherein an output negative path exited from the inverting, negative path balanced distortion circuit comprises a first full waveform;
• passing a second signal through a non-inverting, positive path balanced distortion circuit following the non-inverting, positive path, and parallel to the inverting, negative path balanced distortion circuit, and adapted to receive a non-inverting, positive path input, wherein an output positive path exited from the non-inverting, positive path balanced distortion circuit comprises a second full waveform;
• combining the first signal and the second signal in an output stage following the inverting, negative path balanced distortion circuit and the non-inverting, positive path balanced distortion circuit, wherein the output stage is adapted to combine a pair of differential inputs, one the output negative path exited from the inverting, negative path balanced distortion circuit, the first full waveform, and two the output positive path exited from the non-inverting, positive path balanced distortion circuit, the second full waveform, to produce an output audio signal;
• canceling incoming asymmetries and beat note modulation in the output stage from the combined pair of differential inputs;
• producing the output audio signal as symmetric;
• and
• distorting, clipping, and limiting, selectively by a user, the input audio signal.