Need to connect an amplifier's speaker output to the mic input on a mixer? Connect a Phantom I between the speaker output and a mic input with phantom power on the mixer, then set the attenuation switch to -40dB.

If your PA is humming because there is a ground loop between a signal source and the mixer. Connect a Phantom I between the signal source and a mic input with phantom power and set the ground switch to Lift.

Need to connect an unbalanced line-level source (ie: a synthesizer, another mixer, an effects device, etc.) to a mic input on the mixer? Connect a Phantom I between the source and a mic input with phantom power and set the Attenuator switch to -20dB.