Applies to: Scarlett, Saffire, Clarett

You should only connect microphones to the XLR Inputs*. Connecting Line Level or Instrument Level signals via XLR will cause these signals to pass through the full Mic Preamp stage.

The Mic Pre is not designed to accept these levels and doing so could produce poor-quality sound, distortion or, in some cases, damage the units. 

See this article for reference: What is the difference between Mic, Line, and Instrument level?

48V Phantom Power should NEVER be applied to any Line or Instrument level outputs and can damage both the Focusrite and other units. XLR connections and Phantom Power are ONLY for use with a Microphone.  

Always check that your Microphone is safe for use with Phantom Power before applying as some Ribbon Mics can also be damaged by Phantom Power. 

*DI Boxes can also be used as they are designed to lower an Instrument Level signal to a Microphone Level.