XLR Microphone not working with phantom power supply I'm using macbook air. My XLR mic works fine without phantom power supply in between, it's just that audio is low. When I use phantom power supply, macbook doesn't detect the microphone. Has anybody faced a similar problem? What's the solution?
You still need a microphone preamp.

As always seems to happen with these mics, they are bought by people for whom it is their first venture into the audio field, beyond a headset mic.

Unfortunately, nothing in any of these ads tells you precisely what you are going to need - nor do they even supply the right cables in the box to be able to do it.
Theoretically, you can get a signal out of them by using a PC's built-in low voltage supply that can power headsets.
In practise, that really doesn't work well at all - so then people buy a phantom supply, without realising they still really need something to get the signal into the computer at good levels.

If you can return that phantom power supply, do so, you don't need it.

Even on the picture for the supply it shows you need to connect it to a preamp.  



Preamps are readily-available with built-in phantom power &amp; USB connection.
They become the instant bridge between your mic &amp; your computer. They supply the correct phantom power to the mic &amp; become a useable input for the computer.

Instead, get anything like the following list obtained by Googling "USB Phantom" -
Random selection on Amazon
Example -  



They run from approx £30 to many hundreds, depending on number of inputs/features etc. All you need as a basic starter kit is 1 mic input with phantom power.

You also need a male-female XLR cable which will connect to the pre-amp's mic input, which those mics are not supplied with.