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Do You Need Phantom Power for Condenser Mics?

So you want to know if condenser microphones need phantom power?

Here’s a table outlining if a condenser microphone type needs phantom power to work:

Microphone TypeNeed phantom power?
USB condenser microphone.No phantom power needed.
XLR condenser microphone with a battery compartment.No phantom power needed.
XLR condenser microphone with no battery compartment.Phantom power needed.
Tube condenser microphone.No phantom power needed (Need external power supply).

Now, we’ll have a deeper look at condenser microphones and if phantom power is necessary for them.

Do you need phantom power for condenser microphones?

All condenser microphones need some sort of power in order to operate. This is because inside the microphone the two metal plates need to be charged in order to create a capacitor. The two metal plates are:

  • The backplate (fixed)
  • The diaphragm (movable)

When the sound reaches the microphone, the diaphragm moves, and the spacing variation between the two charged metal plates produces the electrical signal corresponding to the actual sound. If no power is supplied, no signal will be recorded.

XLR Condenser

XLR condenser microphones generally need phantom power (+48V) to work, but some can operate using batteries. If the condenser microphone does not have a battery compartment, it will need phantom power supplied to it.

Phantom power is supplied to the condenser microphone via the XLR cable, so there is no need to have another power-supplying cable.

When phantom power is turned on, the current will pass through the XLR cable through pins 2 (hot/positive) and 3 (cold/negative). Since XLR is a balanced cable, sending electricity through both lines will make them cancel each other out, resulting in a clean audio signal.

USB Condenser

USB condenser microphones do not need phantom power, since power is supplied directly via the USB cable.

Simply plugging in your USB condenser microphone to your computer’s USB port will not only supply the necessary power needed to run the microphone but will also transfer the audio signal from the microphone to the computer.

Can condenser microphones record without phantom power?

When it comes to recording with an XLR condenser microphone without phantom power, and it requires phantom power to operate, the resulting audio signal will be either inaudible or extremely low in volume.

Technically you could record without phantom power. However, because the audio signal is so low, the noise will be extremely loud if you turn the overall volume up, resulting in a recording that is unusable.

This is called the signal-to-noise ratio, comparing the level of the desired recording and the background noise. Note that the background noise is extremely hard to reduce and nearly impossible to eliminate.

Therefore, I personally would advise against recording without phantom power turned on when using an XLR condenser microphone that requires phantom power to run. These microphones were not designed to be used in this manner. Feed it the power it needs! You won’t regret it.

How do you provide phantom power to the condenser microphone?

When it comes to providing phantom power, most modern audio interfaces and mixers will have phantom power built-in. Just look for the (+48V) button, press it, and it should be on. Usually, there’s also a light that lights up when it’s on.

Phantom power works by supplying electricity directly through a balanced audio cable. In our case, the same XLR cable you’re using to connect the condenser microphone to your audio interface or mixer. That means simply connect your condenser microphone as usual, turn the phantom power (+48V) switch on, and you’re all set!

Most audio interfaces and mixers nowadays have separate phantom power for each microphone input. In that case, it is relatively straightforward to turn on phantom power on the channels you need and leave the rest off.

However, some audio interfaces and mixers may have a global phantom power switch. This is when you need to be careful how you use it. When you switch the global phantom power switch on, all of the channels will be supplied with phantom power. This means it does not matter what microphone you’ve connected, every single microphone connected to any channel will receive phantom power.

If your audio interface or mixer has a global phantom power switch, DO NOT connect your vintage passive ribbon microphone to ANY input channel. If you do, it will most likely damage your microphone. Otherwise, if you’re connecting dynamic microphones along with condenser microphones, it is generally fine to turn the global phantom power switch on.

Do you need phantom power for dynamic microphones?

Generally, dynamic microphones do not need phantom power. However, there are some exceptions.

Here’s a table with different types of dynamic microphones and if they need phantom power to operate:

Microphone TypeNeed phantom power?
XLR Moving-coil dynamic microphoneNo phantom power needed.
Passive ribbon dynamic microphoneNo phantom power needed.
Active ribbon dynamic microphone (FET)Need phantom power.
Active tube ribbon dynamic microphoneNo phantom power needed (Need external power supply).

Moving-Coil Dynamic

When we’re talking about moving-coil dynamic microphones, unlike condenser microphones, they are passive and do not require power to operate.

A good practice is to turn off phantom power if you’re using a dynamic microphone. You’ll save a bit of power while eliminating the confusion caused if you use many different types of microphones in your studio.

Passive Ribbon

Passive ribbon microphones do not require power to work. However, as you can see from the table above, active ribbon microphones need a power source to operate. FET ribbon microphones specifically need phantom power.

Note that some vintage passive ribbon microphones will actually be damaged from phantom power, so if you’re using a ribbon microphone make sure no phantom power is supplied to it. However, most modern ribbon microphones have a transformer on the output, therefore even if phantom power is turned on, the microphone will not be damaged at all.

It is recommended that if you’re using a passive ribbon microphone, even if it’s a modern microphone, turn phantom power off. Not only you will save a bit of power, but you’ll save yourself headaches down the line if you happen to obtain vintage ribbon microphones.

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