Is Phantom Power Bad For Dynamic Mics?

Microphones are built differently and because of this, they pretty much work differently depending on the work they are meant to deliver to the user.

Dynamic microphones for example don’t require phantom power which is necessary for most condenser microphones.

Phantom power is 48 volts that is necessary to power on a condenser and without it most condenser mics except USB condenser microphones won’t work.

This leaves a lot of questions about dynamic microphones…

This post is going to address one of these questions and provide some necessary insight…

With that said,

Is phantom power bad for dynamic mics?

Most premium dynamic microphones are meant to resist phantom power from damaging them. However, using a low quality dynamic microphone with phantom power won’t do it any favors. You’ll most likely notice the bad tonal change and it will be possible that phantom power may be frying it from the inside. Which is why it’s not advisable to enable phantom power on dynamic microphones unless they’re active dynamic microphones.

What is Phantom Power?

I’m basically going to give you a less technical definition of phantom power…. and I will avoid going too far into the technical aspects of phantom power because I don’t want beginners to get lost.

The basics are that….phantom power is just a positive voltage (from 12 volts to 48 volts DC) that runs on pins 2 and 3 in an XLR cable.

The word phantom is used to describe it because the power source is essentially invisible, as it runs through the same cord that the audio signal flows through.

On most audio interfaces you’ll likely run into a switch labeled P48 that turns phantom power on and off – the 48 simply stands for the highest voltage rating.

Why Do Condenser Mics Need Phantom Power?

Condenser microphones unlike dynamic microphones need phantom power as you’ve obviously discovered.

Therefore, the basics are this…condenser microphones have what we refer to as active electronics that need an external power source in order to function.

Dynamic microphones are mostly passive and therefore do not need phantom power.

Because of the way condenser mics work, their output is very high impedance, and therefore requires a powered circuit to reduce that impedance.

However, active dynamic microphones may require some phantom power depending on their specifications.

Dynamic Microphone reaction to phantom power

Lets look at how dynamic microphones may react when you hook them up to phantom power so you get a better understanding of what is likely to happen.

Tonal change

The most common reaction that I’ve noticed when I plug phantom power into a premium or more expensive dynamic microphone is that it’s output will greatly differ.

The output will have a difference in tone when you compare it with how it sounds naturally.

You may sometimes notice that your mic output lacks low end and part of the mid frequencies..  which is an indication that the inner circuitry of dynamic microphones doesn’t support or need power.

You could notice sparks

Some low sub standard microphone may sound like their internal circuitry is being fried which more than often is the case.

If you unscrew the grille you’ll most likely notice and see these sparks. The signal may also have characteristics of vinyl crackle.

To avoid damaging your dynamic microphone…it may be wise to use it without any extra added power.

Nothing at all

Some dynamic microphones won’t react to phantom power at all. It may simply be quiet and not react in any manner. But this doesn’t mean its okay to use it.

If your dynamic microphone is passive leave it be, if its an active dynamic microphone on the other hand you may need to check specifications of how much phantom power you need in order to make it functional.

Why you shouldn’t turn on phantom power on dynamic mics

I’m going to discuss why you shouldn’t use phantom power with   passive dynamic microphones.

Its not required

This may seem like a no brainer but for somebody that doesn’t have experience working with microphones, they may mess up and turn on phantom power.

You don’t need and shouldn’t turn on phantom power on a passive dynamic microphone because it is not required in order to make these microphones functional.

You may mess up a good mic

Like I’ve previously explained not all dynamic microphones are created equal… you wouldn’t expect to get the same quality from a microphone with cheap parts simply assembled…

With that said, running phantom power into some microphones may not necessarily cause so much damage but could affect its output.

So you should pay attention to your microphone specifications and use it as specified.

It’s a waste of time

Lastly, using phantom power on a passive dynamic microphone is just a waste of time.

Some people think it may improve output but that is not true at all.

So you don’t need phantom power for a passive dynamic microphone.