Abstract: A variable voltage phantom power supply assembly includes a phantom power supply unit having a power input, and one or more audio channels. The variable voltage phantom power supply assembly also includes a variable voltage phantom power supply module having a phantom power supply circuit with a variable voltage controller and a variable voltage phantom power output. A method of customizing at least one performance characteristic of a microphone includes: modifying a phantom power supply to provide a variable voltage phantom power output; connecting a microphone to an input of a variable voltage phantom power supply assembly; adjusting the voltage output of the variable voltage phantom power supply to the microphone; monitoring the performance characteristics of the microphone; and, readjusting the voltage output of the variable voltage phantom power supply to the microphone to obtain at least one desired performance characteristic of the microphone.