Almost all commercially available microphone amplifiers draw their power from a 48V phantom power supply. If this is unavailable or unsuitable, the solution is to build a self-powered amplifier.

48 V ‘phantom’ powering has become the standard for professional condenser microphones. The supply (or rather bias) voltage is applied over both wires of the balanced screened cable via two 6k8 ...

I'm running Ubuntu Studio (just upgraded to 14.10) with a Presonus AudioBox 2x2 USB audio interface. For Christmas I got myself a new MXL 990s condenser mic (60% off, sweet!), but when I plug it in ...