The plug in power at the 3.5mm input is not enough to prevent distortion in loud situations. The first recording I made was using straight plug-in power and the lows in the recording were very distorted. You need 9v.
The only switch for providing phantom power is the 48v switch for using the 1/4" jacks. However, the MT1 has a switch for line/mic, which if you're using no preamp, run mic in.