This balanced-line attenuator is used to prevent low-impedance microphones (rated at 150 or 600 ohms) and high-output condenser microphones from overloading low impedance inputs in high sound pressure level applications. The values of attenuation can be switch selected for 15, 20, or 25 dB. Use the A15AS with any low-impedance microphone, including phantom-powered condenser microphones, such as the Shure SM81. It can be used in line between the microphone and its power supply. (This model is not suitable for use with the condenser powering system called "A-B Powering.") The A15AS attenuator bridges the microphone output and allows maximum signal handling with a minimum of loading-caused distortion or reduction in clipping level.