Different condenser microphones specify different amounts of required phantom power. As a rule these ratings can range from 48 volts all the way down to 9 volts. Fortunately, there is some flexibility in terms of matching phantom voltage to your mic. A rough rule of thumb would be 'more is better.'
For example, a 24-volt condenser mic will run perfectly on 48 volts. In fact, mics rated at as little as 9 volts can often operate on 48 volts, but you should 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 obtain best results with 48 volts of phantom power. The Phantom I is a great choice for the above needs.
The ARTcessories line includes direct boxes, headphone amplifiers, small mixers, mic cable combiner/splitters and much more. The ARTcessories line is designed to deliver solutions for a number of audio needs - like having phantom power, having 1 or 2 more mixing channels, testing cables, headphone processing, preamplification for microphones & turntables, and many more real-world applications. ARTcessories are a 'must have' for stage and studio, and will satisfy the needs of working musicians and sound engineers everywhere.