The Kopul PDI-40 High-Performance Passive Direct Box lets you connect an unbalanced, high-impedance signal to a balanced, low-impedance input. It is most often used for plugging a keyboard, electric guitar, or electric bass guitar directly into a mixing console's microphone-level input. The PDI-40 can also be used in DJ applications for converting unbalanced +10 dB DJ mixer signals to balanced, line-level signals. This allows you to connect your DJ mixer to a mixing console and cuts down on noise that can be picked up in longer cable runs.
For live performance and recording applications, the PDI-40 features a parallel output for connecting your instrument to an amplifier, while simultaneously sending signal to the mixer. There is also an attenuation switch to lower the signal input by -20 or -40 dB, and a ground-lift button to minimize hum and noise caused by ground loops.