Applies to: All units
There are multiple types of microphones in the world. Commonly the main two you will come across in a home studio are Dynamic and Condenser.
Dynamic microphones capture sound waves by means of electromagnetism and need nothing more than a source of audio to function once plugged in.
Condenser (or Capacitor) microphones however need an electrical current to move the diaphragm, which is what captures the sound. This is where the Phantom Power comes in, Phantom Power (the 48v button) sends 48 volts of electricity via the XLR cable which activates the capacitor and essentially 'turns on' the microphone. It is important to note that Phantom Power will only travel through an XLR to XLR cable.
Using Phantom Power with a Dynamic microphone should not damage the microphone but is not needed. A Condenser microphone will not be damaged if Phantom Power is not engaged, though it will not pass any audio.
If you are unsure whether or not your microphone is a Dynamic or Condenser please contact the manufacturer.
*The Scarlett CM25 (Bundled with the Studio Packs) is a Condenser microphone and will need Phantom Power.