If you don’t know anything about home recording, Phantom Power can be confusing. So what is it? Phantom Power is an industry-standard approach of transmitting DC voltage via an audio cable to supply power to professional audio equipment.
The technique was initially developed to allow condenser microphones to operate without batteries. Phantom power is also commonly used to power active DI boxes and other audio devices. The voltage is usually supplied by a mixing console, preamplifier, or other audio devices.
In this article, we’ll provide an in-depth guide in unraveling the mystery of phantom power and its role with microphones.
Phantom Power: Definition
As mentioned above, phantom power is a method of supplying power to microphones. It is provided by audio interfaces, mixing consoles, microphone preamplifiers, and standalone phantom power supplies.
Phantom power gets its name from the phantom or ghost images that appeared on early television screens. These images were caused by a 60 Hz electrical current on all televisions but were not visible to the naked eye.
The same principle applies to phantom power in audio systems. The 48 volts DC is too low for audio monitoring but is strong enough to power active microphones. A single standard connector carries the entire phantom supply.
History Of Phantom Power
Phantom power was initially introduced in the year the 1960s. It used to be a popular way of powering ribbon microphones, as many condenser mics have been designed to work with it from the start.
In 1904, Sir John Ambrose Fleming invented the vacuum tube, and in 1905, the first triode vacuum tube was created by Lee De Forest. It wasn’t until 1928 that the tube condenser was invented. This new design was a significant advancement in microphones, as an external power supply could now power them.
Schoeps produced the first-ever solid-state microphone (CMT20) in 1965. And in 1966, Neumann released the CMV3, the world’s first phantom-powered microphone.
How Does Phantom Power Work?
Now that we know a little history about phantom power let’s look at how it works.
As mentioned earlier, phantom power transmits DC voltage via an audio cable to supply power to professional audio equipment.
The following steps outline how phantom power works:
This power supply is very low voltage, usually around 48 volts, and it cannot be detected electrically by most microphones because of the high impedance of its internal transducer element. Microphones that do not require such a power supply (e.g., dynamic microphones) do not sense this voltage at all.
When the audio devices are plugged in, they transmit DC across the two wires of the balanced output cable. Usually, this is done using a charge pump circuit. This current passes through the microphone’s transducer element (at about 2mA), creating a voltage across it.
The polarity of this voltage is opposite to the voltage created by the audio signal, which is why a transformer is used to step down the voltage and create a common ground for both signals.
Phantom Power Standards
The general standard for phantom power is 12 to 48 volts of DC power transmitted on a balanced line (3 or 3.15 mm TRS connector) along with the audio signal, resulting in a current flow of 2 mA.
The actual voltage can be anywhere from 9 to 52 volts. It is all relative to the connected equipment. The standard for phantom power is 48 volts. However, there are some variations in the voltage, as different devices require different voltages to operate correctly.
For example, most ribbon microphones require a higher voltage of 52 volts to function correctly. And some condenser microphones can operate with as low as 9 volts.
Will Phantom Power Affect The Audio Signal?
No. Phantom power will not affect the quality of your audio signal in any way. It is just a way of transmitting power to microphones and other pro audio equipment.
However, if you use a low-impedance mic with a high-impedance input (like a guitar amp), you may get some noise from the phantom power supply. There is a voltage difference between the two devices, and the amp will “hear” this as noise.
What Is Digital Phantom Power?
Digital phantom power is a term that applies to phantom power in digital audio systems. The Audio Engineering Society (AES) issued AES42, which standardized 10 volts of DC phantom powering in digital audio equipment. If your gear is designed to receive digital phantom power, it will automatically detect it and adjust its internal circuitry accordingly.
Digital phantom power supplies transmit their power through XLD or XLR connectors. They can be found on audio distribution equipment, digital microphones, and audio interfaces. Currently, the standard voltage is 12 volts. However, 10 volts is more widely used.
Phantom Power vs. Battery Power
There are some pros and cons to using phantom power vs. battery power:
Pros of Phantom Power
- You don’t have to worry about changing batteries
- It is more reliable than battery power
- It is less susceptible to interference than battery power
Cons of Phantom Power
- It can be more expensive than using batteries
- You need to have a phantom power supply available to use it
Pros of Battery Power
- Battery power is cheaper than phantom power
- You don’t need any special equipment to use it
- It is less susceptible to interference than phantom power
Cons of Battery Power
- Batteries can run out of juice unexpectedly
- They can be heavy to carry around
If you don’t want to have to worry about changing batteries, then phantom power is the way to go. But battery power is the more affordable option if you’re on a tight budget. And if you’re worried about interference, battery power is the better choice. It all comes down to what works best for you and your needs.
What Types Of Microphones Require Phantom Power?
Most condenser microphones require phantom power, but they can also be used with dynamic microphones and ribbon microphones. You just need to make sure that your microphone is compatible with phantom power before you try to use it with a phantom power supply.
If you’re not sure if your microphone requires phantom power, consult the manufacturer’s specifications or do some research online. There are plenty of resources available that will help you determine whether or not your microphone needs phantom power to operate.
Should You Turn Off Phantom Power Before Plugging in a Microphone?
Yes, and you need to make sure you also turn off the power before you disconnect the mic.
If you’re using an XLR cable with a 48 volts battery, turn the phantom power off before plugging in your microphone. It will eliminate any loud pops or sudden changes in volume when you connect it.
Phantom power is a way of transmitting power to microphones and other pro audio equipment. It is a standard feature on most digital audio systems, and it can also be found on audio distribution equipment, digital microphones, and audio interfaces.
It is essential to understand that there are two types of phantom power: digital phantom power and analog phantom power. Digital phantom power is standardized, whereas analog phantom power isn’t.
There are some pros and cons to using both battery power and phantom power, but if you want the best option for reliability, then go with the standard 12 volts of phantom power. Just make sure your microphone is compatible with phantom power before you try to use it.
Eduardo Perez is a multi-instrumentalist with over 20 years of experience playing instruments such as piano, guitar, ukulele, and bass. Having arranged songs and produced music in a recording studio, he has a wealth of knowledge to share about analyzing songs, composing, and producing. Currently pursuing a Bachelor of Arts degree in Interdisciplinary Musical Studies at Berklee College School of Music. Featured on Entrepreneur.com. Subscribe to his YouTube channel, or follow him on Instagram.