Patent ID: 8130981

Claim:
A sound card comprising: at least one amplifier having at least one amplifier input and at least one amplifier output; at least one sound card input connected to said amplifier input; at least one sound card output connected to said amplifier output; at least one feedback loop connected to said amplifier input and said amplifier output; a feedback controller in said feedback loop; at least one input voltage controller connected between said sound card input and said amplifier input; and at least one sound card controller connected to said input voltage controller, said amplifier, and said feedback controller, said sound card controller adjusting an output voltage of said amplifier to maximum voltage and supplying a signal having a frequency to said amplifier, said feedback controller increasing a voltage of said feedback loop, as said signal is supplied to said amplifier and said output voltage is at said maximum voltage, from minimum voltage until an over-saturation condition occurs, said over-saturation condition comprising a condition where harmonics of said signal begin being output from said amplifier, said feedback controller further decreasing said voltage of said feedback loop until said harmonics stop being output from said amplifier, and said sound card controller measuring said voltage of said feedback loop as an output voltage limit when said harmonics stop being output from said amplifier and subsequently restricting said output voltage of said amplifier to being no more than said output voltage limit.