What does 48v do on Focusrite audio interfaces? Focusrite Scarlett 2i2 has a 48v button that allows you to disable or enable phantom power. When using in-line preamps and condenser mics, this is necessary. For dynamic microphones and ribbon microphones this power isn’t necessary, but it is for in-line preamps. Focusrite Scarlett 2i2 has an integrated 48v button. This allows you to toggle between 48V and phantom power for your microphones.