I often get the question “Is it safe to use and XLR Y cable with phantom power?”. The short answer is yes, but there is sometimes confusion when it comes to phantom power, so I thought it might be helpful to answer the question in a little more detail.

Phantom power consists of a DC voltage supplied to the XLR connector of a  condenser microphone. This is commonly 48 volts DC, but can be as low as 9 volts depending on the microphone you’re using.  If you’re not sure check the manual that came with your microphone to find out for sure.

The XLR female to 2 XLR male Y cable is a very handy tool and can be used to feed the output of a microphone to both the left and right inputs of your field recorder. To find out more about splitting your audio into two channels check out this earlier post.

Basically the Y cable splits the audio output of the microphone into 2 paralleled paths. This means that the 48 volts DC supplied from each XLR connector on your field recorder is also in parallel. Without diving to far into electrical theory, two equal DC voltages in parallel remain the same voltage. If you wanted to test this out at home you could hook 2 fresh batteries positive to positive and negative to negative and place a volt meter across the terminals. If you’ve done everything correctly your volt meter will read the same voltage value as either of the individual batteries.

As you can see I have this at4073a mic plugged in using the Y cable with the volume for the left and right channels set to different levels with no harm to the microphone. 48 volt phantom power supplied by the Tascam DR-40 is safely delivered to the microphone and you now have 2 independent audio levels to work with.

On a side note, if you are a Tascam DR-40 user, the Y cable isn’t necessary. This is because it has a dual mode that allows you to record a single input at 2 different levels (up to -12db). I’ll walk you through how to set that up in another post.

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