This is a high-quality, fully passive interface with a powerful isolation transformer for connecting various signal sources (with instrument, line, or speaker levels) to a mixer or other balanced inputs. The signal entering the high-impedance, unbalanced jack is converted by the transformer into an isolated, balanced, and low-impedance signal. It can also handle high signal levels and provide a very clean, neutral sound across a variety of signal sources, even over long signal paths and in noisy environments. Adjustable input attenuation allows for adaptation to different signal levels. A parallel through socket enables the device to be inserted into the signal chain. The ground lift switch provides complete ground isolation between the input and output signals when needed, helping to prevent hum and ground loops. When using the Zdirect as an interface between an audio workstation and its monitors, a switchable low-pass filter eliminates high-frequency interference and reduces any potential digital noise. A phase reverse switch allows you to invert the polarity of the signal directly at the input. This feature is especially useful when you want to blend a direct signal with a microphone signal in your mix.