YES! Duet 2's preamps can be bypassed if you'd like to connect a line level input source such as an external microphone preamp or mixer.
Here are the two things you'll need to do:
- Connect the devices line level output to Duet's combination input jack using an XLR cable.
- Go to the input tab in Maestro (found in your Applications folder) and change the input selection from "Mic" or "Inst" to "+4 dBu" or "-10 dBV".
The line level selection will depend on the type of gear you're connecting. Professional audio equipment most often uses +4 dBu, while consumer audio gear is set to -10 dBV.