Simply plug your 1/4" output from a guitar or electric piano, plug an XLR cable into your mixer's channel input, and you're done.
Stage Right by Monoprice Sound Block Passive Direct Box with Ground Lift and Attenuator Features: Heavy‑duty 14 gauge steel construction Bidirectional impedance matching Use with high output signals, including speakers ‑20dB and ‑40dB pad options Easy to use passive electronic device Control hum and buzz from stage with the ground lift 50 ohms TRS parallel input impedance 50 ohms TRS Parallel output impedance 600 ohms XLR‑M balanced input and output impedance Support Files: Quick User Guide (Apr 29, 2016) Monoprice™, Stage Right™, the Stage Right logo, and all Monoprice logos are trademarks of Monoprice Inc.This Direct Interface is extremely versatile as a Lo to Hi‑Z transformer for electric instruments and devices to XLR mic inputs or as Lo‑Hi‑Z to use a microphone with a guitar amp (not recommended only because guitar amps make terrible PAs).