For example, a 24-volt condenser mic usually works perfectly with a 48 Volt Phantom Power Suppy. Some mics rated at as little as 9 Volts can operate on voltages up to 48 Volts (check with the manufacturer first). Conversely, a mic will generally perform best driven by not less than its rated voltage. So, for a 48 Volt mic, you would get best performance with 48 Volts of Phantom Power. For all the above, check out the ART Phantom II.