Phantom power is a commonly used way of supplying power to microphones in the recording industry. But does it hurt microphones if we leave it on? Especially if the microphones don’t need it?

Here’s a short and concise answer:

Phantom power will not hurt microphones that don’t need it. Most modern dynamic and condenser microphones that don’t require phantom power will automatically detect and reject it. However, if you have a vintage ribbon microphone, make sure it can handle phantom power, otherwise you risk damaging it.

Now we’ll take a look at different microphones and how they handle phantom power.

Can phantom power hurt microphones?

If your microphones are all connected and wired up properly, and you’re using high-quality XLR cables, your modern microphones should not be damaged by phantom power even if they don’t need it. In fact, in many studios around the world, phantom power is always engaged on the mixer, and people just plug the microphones in and out without any problems at all.

Using an balanced XLR cable is very important. The XLR connector has 3 pins:

1. Earth
2. Positive/hot
3. Negative/cold

XLR cables are designed in a way so that the earth pin will connect first, then the other 2 pins will connect simultaneously. This is achieved by having the earth pin slightly longer on the male connector and having the other two pins with the same length.

Using the XLR design, microphones are protected from having significantly unbalanced phantom voltages, so the chance of damaging the microphone is basically zero. Note that because the voltage is exactly the same on pins 2 and 3, phantom power will not have any effect on balanced dynamic microphones.

The only time you need to worry about damaging your microphone is when instead of a modern microphone, you have a vintage ribbon microphone. Many vintage ribbon microphones aren’t designed to be able to reject electricity from phantom power. Otherwise, you’ll be fine with modern microphones.

Phantom power best practices

How phantom power works

Phantom power works by supplying electricity through a balanced XLR cable, the same cable that is used to transfer the audio signal from your microphone to the audio interface or mixer. Due to the convenience and the safety of using the technology, it has become a worldwide standard for supplying power to microphones.

If you have trouble locating the phantom power switch on your audio interface or mixer, it is typically labelled as (+48V). When engaged, there should be a light indicator that lights up.

Phantom power was actually specially designed in a way that does not damage microphones when connected using a balanced XLR cable. In other words, if you connect a dynamic microphone, which typically doesn’t require phantom power, phantom power will not damage it. Most modern microphones can reject phantom power if they don’t need it.

When should I turn phantom power on?

Technically, if you’re only using modern microphones and no instruments, you can leave phantom power engaged the whole time. However, there are some best practices you can follow.

First, do not plug line instruments into XLR inputs when the phantom power is on. Otherwise, you risk damaging your instrument. This includes guitars, electric pianos, and so on. Although the chance of actually causing damage is quite small, turning phantom power off when using line instruments is recommended.

Secondly, do not plug in a vintage ribbon microphone that has a center-tapped output transformer. If you do, you will short-circuit the phantom power supply and cause damage to the microphone. Either you choose to not use a vintage ribbon microphone in a recording studio that uses phantom power, or you can modify the ribbon microphone so that it won’t be damaged by phantom power.

Thirdly, turn phantom power on after connecting microphones, not before. And turn off the phantom power before unplugging the microphone cable. Although you probably won’t damage the microphones, you may hear a loud pop from your headphones and speakers. If you would prefer to leave the phantom power on, just keep the faders down when plugging in or unplugging the microphone.

Lastly, it is advised that you only turn only phantom power for the channels that are connected to microphones that actually require phantom power. Not only you’ll save a tiny bit of power but also it is convenient to look at the mixer and get a sense of how many condensers are being used, as usually condenser microphones are the ones that require phantom power. If your audio interface or mixer only has one global phantom power switch, feel free to leave it on for the entire recording session.

Does your microphone need phantom power?

If you’re not sure about whether your microphone needs phantom power, here’s a general guide:

However, the above table is simply a generic guide to follow. You should either look up the microphone manual, or ask your retailer for confirmation.

Can you record without phantom power?

If you’re using a dynamic microphone, more often than not you’re supposed to record without phantom power. That is because most modern dynamic microphones are designed to work without phantom power.

However, if you’re using a condenser microphone, you should record with phantom power engaged. The reason behind this is that the condenser microphone is designed to have two charged metal plates in order to function. Without electricity, you either get an extremely low signal or no signal at all. If you’re wondering whether the tiny signal you get from condenser microphones without phantom power can be boosted in your software, please don’t do it. You’ll save yourself a lot of time and effort. The background noise will be so loud that the recording will be basically unusable.