What do I need to power a condenser mic?

Condenser mics are an interesting kind of mic. Here is the construction of a condenser mic. The 'element' consists of backplate with a mylar diaghram in front of it, separated by a small distance. As the diaghram moves, the distance between the front mylar diaghram and the backplate changes, and this change in distance changes the voltage. This voltage change is transmitted to the preamp, and there is your signal!

Now, a condenser mic can not work without a supplied voltage, which is typically 48 volts. The condenser mic does not create a voltage on its own, so it requires the preamp to supply it. Almost every mixer has a switch labeled 'phantom power', and by engaging this switch, it turns on the 48 voltage supply. While the power in engaged, there is no problem with using dynamic mics. However, never attach a ribbon mic to a 48 volt circuit, since that will most likely destroy the mic!

What if you don't have a mixer, but are using your computer? Then you should use a professional sound card. Most will be able to supply phantom power, pulling power off the USB or firewire connection. Please note that if you are using a laptop, it will drain the power off the battery more quickly, so you should use your system with the power plugged in.

What if you don't have a mixer or pro level soundcard? Then there are small devices that you can get which simply supply phantom power, or, you can outboard microphone preamps. These are typically referred to as 'mic pres' for short. We would suggest getting a dedicated mic pre, since the sound of a real mic pre will outperform an onboard mic pre.

Hope this helps.