Phantom Power: This is What You Need to Know

So, you’ve bought a new microphone only to find out that it won’t work unless you supply it with phantom power. Condenser microphones in particular often require this. Fortunately, most mixers, audio interfaces and recorders have a built-in phantom power supply, the control for which is indicated by ‘Phantom’, ‘P48’ or ‘48V’. In this blog, I’ll tell you what to look out for when you want to use phantom power.

The Technical Side of Things
+48V Phantom Power or Less?
How to Connect a Microphone to Phantom Power
Use with Dynamic and Ribbon Mics
Other Types
My Mixer Doesn’t Have Phantom Power!
See Also

The Technical Side of Things

Phantom power is the direct current that runs in the positive and negative signal of a balanced connection. Because the voltage is spread across two wires, advanced circuitry is able to ensure that any signal noise you’d normally get is countered. Hence, it’s important that the voltage on both wires is exactly the same at all times, since a wrong or worn out cable can easily damage your microphone beyond repair. Phantom power is only found on XLR microphone inputs and doesn’t work with TS/TRS jacks because the contact points don’t all connect at the very same moment, while they do in the case of XLR connections.

+48V Phantom or Less?

While they’re more rare, there are relatively simple mixers and other devices out there that come packed with less than +48V phantom power. Most condenser mics and other active models will work just fine in combination with these devices, but they’ll have less headroom to work with, meaning loud audio sources can start to distort much sooner.

How to Connect a Microphone to Phantom Power

When you want to hook up your microphone, it’s important to carry out the steps in the right order. Before you plug in, make sure that the phantom power supply is turned off, and only turn it on once the microphone has been connected and requires phantom power. If you don’t, you’ll hear a loud pop. In most cases, there’s only one on/off switch for the phantom power for all available mic inputs, so unplug any connected microphones that don’t need or can’t handle phantom power, such as old-fashioned ribbon mics (more on these in the next bit). When you’re done recording and want to unplug your mic, turn off the phantom power first and then wait about 30 seconds for the circuitry to ‘run dry’. If your recording device doesn’t have a separate phantom power switch, at least turn the gain and fader of the relevant channel down before you unplug.

Phantom Power: This is What You Need to Know

Use with Dynamic and Ribbon Mics

Phantom power activates the condenser capsule of a condenser microphone to feed the tiny internal amplifier, but some dynamic and ribbon microphones actually feature the same active design and thus require phantom power. Regular passive dynamic microphones don’t require phantom power, nevertheless, as long as you’re using a good-quality cable, it won’t hurt them should they receive some. Passive ribbon mics, on the other hand, are a completely different story, and especially classic models from RCA and Coles are known to give up the ghost when they’re hit with a bit of phantom power. Modern ribbon mics are a little more resistant but I still wouldn’t recommend trying this out.

Other Types of Phantom Power

The film industry thankfully continues to use T-power and A-B powering. These are 12V systems that, just like phantom power, need a balanced connection (cable) to the microphone. T-power and phantom power are not interchangeable, though.
Plug-in-Power (PiP) is generally found on consumer equipment, including the microphone inputs of computers, laptops and phones. We’re talking 3 to 5 Volts here, so any mics made for PiP are not compatible with phantom power.

My Mixer Doesn’t Have Phantom Power!

If your mixer or audio interface isn’t packed with phantom power but you desperately need some, you could opt to use an external phantom power supply. Simply hook up your microphone and in turn, connect the power supply with the microphone input of your mixer or interface. Voila!
Phantom Power: This is What You Need to Know
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