Abstract: The present invention relates to a musical instrument amplifier which is particularly useful for electric guitars. The amplifier has a rigid body for housing both the electronic system for amplifying and processing signals from the guitar and the system's power supply. An input plug connected to and projecting from the body is electrically coupled to the signal amplifying and processing system. When the plug is inserted into an output jack for an electric guitar, the body is rigidly carried by the guitar, and the guitar is operatively connected to the electrical amplifying and signal processing system without use of a loose interconnection cable. The amplifier is provided with an output jack, into which headphones are plugged to receive amplified signals from the guitar. By eliminating the conventional interconnection cable, the amplifier of the present invention can be used by musicians with increased flexibility and greater freedom of movement.

Abstract: A system is provided for use with an electrical musical instrument for conditioning electrical signals generated by said instrument. Said system comprises an amplifier circuit having input means for responding to said signals and output means for providing a conditioned output signal, and at least one compressing means operatively connected to said input means for responding to the amplitude of said electrical signals to provide a compressed signal to said amplifier circuit that is variable as a nonlinear function of said amplitude.