A switch on a DI box or piece of gear that disconnects the signal ground from the chassis or cable shield ground, used to break ground loops that cause 50/60 Hz hum.
A ground lift is a physical switch that breaks the connection between the audio signal ground and the safety or chassis ground at one point in a signal chain. Its purpose is to eliminate ground loops: situations where two or more pieces of equipment connected together create a closed loop through their ground paths, inducing a low-frequency hum.
Why it matters
A DJ rig connected across multiple power outlets or to venue power can pick up a consistent 50 or 60 Hz hum through the ground circuit. Engaging the ground lift on a DI box at the point where the hum enters the chain is often the fastest fix without rewiring the whole rig.
In practice
Start with the lift switched off (ground connected), which is the safe default. If you hear hum, engage the lift one device at a time rather than lifting every ground simultaneously. Once the hum disappears, leave only that lift engaged. Do not rely on ground lift as a substitute for proper cable routing or power conditioning.
