Inventors:
Richard J. Comeau - Cape Girardeau MO
Assignee:
Digital lab Studios, L.L.C. - Cape Girardeau MO
International Classification:
H03F 304
Abstract:
An active direct box comprising an electronic circuit for receiving an unbalanced, high-impedance format audio signal input, and for providing a balanced, low-impedance audio signal output, compatible with common audio system components such as audio consoles and recorders. The direct box circuit receives power from a phantom power source supplied by the audio system component to which the direct box is connected. The phantom power source is isolated, and used to provide a bias supply to a pair of JFET operational amplifiers in the electronic circuit which convert the audio signals, and which provide for both signal gain and signal reduction. A negative feedback system is further employed to covert the input audio signals to a low-impedance format with a minimal introduction of signal distortion.