Using the dbx Di4 as a DI Box:
Connect the signal you would like to convert from unbalanced to balanced to the Di4 via a 1/4-inch unbalanced jack to one of the channel inputs on the front panel of the unit. Connect an XLR balanced cable to the corresponding channel output on the rear of the Di4 and connect to your chosen destination. If the input signal strength is too high you can depress the 20dB pad. If there is an ground (earth) loop hum you can remove by depressing the earth lift switch.
Using the dbx Di4 as a Line Mixer:
You can mix volume and pan of all input signals to a single stereo pair of RCA connections on the rear of the Di4. This enables use of the unit as a fully functional line mixer. Just connect the RCA stereo master outputs on the rear to your chosen destination and adjust the individual volume and pan controls for each individual channel on the front of the Di4 to suit your needs.
Four totally independent DI box units in 1/2 RU package
Independent 20dB pad switch per channel
Independent ground (earth) lift switch per channel
Independent volume control per channel for line mixer output
Independent pan control per channel for line mixer output