When Headphones Need a DAC or Amp

What a DAC and an amplifier do

A DAC, or digital-to-analog converter, turns the digital audio file into an analog signal that headphones can turn into sound. An amplifier then increases the power of that analog signal before it reaches the headphone drivers.

In a wired headphone setup, the DAC and amplifier are typically either inside the source device, such as a phone, laptop, or desktop computer, or inside a separate box you connect between the source and the headphones. Many portable devices have a combined DAC and amplifier chip that is designed to drive efficient headphones.

Wireless headphones, on the other hand, contain their own DAC and amplifier inside the ear cup or earbud. They receive a digital Bluetooth signal and convert it to analog before amplifying it. That is why they do not need an external DAC or amp.

Impedance and sensitivity: the two numbers to read

Impedance is a measure, in ohms, of how much the headphone resists the electrical current from the amplifier. A higher impedance generally means the headphone requires more voltage to reach a given loudness. Common values range from 16 ohms for portable earbuds to 600 ohms for some studio headphones.

Sensitivity describes how efficiently a headphone converts that electrical signal into sound. It is usually stated in decibels per milliwatt (dB/mW). A more sensitive headphone will play louder with less power than a less sensitive one. For example, a pair with 100 dB/mW sensitivity will produce the same loudness with less power than a pair with 90 dB/mW.

When a listing states impedance and sensitivity, you can use them to compare how much power each pair is likely to need. A low-impedance, high-sensitivity pair is easy to drive from a phone. A high-impedance, low-sensitivity pair may need a dedicated amplifier.

Reading impedance and sensitivity on a listing

When you look at a headphone listing, the impedance and sensitivity may appear in the specifications section. If they are not stated, you can sometimes infer from the headphone's design: on-ear and over-ear models for portable use tend to be efficient, while studio and reference models may be built for higher power sources.

If the listing says "studio headphones" or "monitor headphones," it is more likely to have higher impedance. If it says "portable" or "for smartphones," it is likely low-impedance and efficient. You can also check the maker's page for the exact numbers.

When your phone or computer is enough

Many headphones are designed for portable sources. Wireless headphones have their own battery-powered amplifier and DAC, so they work with any Bluetooth audio source. Wired headphones aimed at everyday listening often have low impedance and high sensitivity, which means a phone or laptop can drive them to comfortable listening levels.

If you are choosing between wireless and wired, see our guide to best wireless headphones and best wired headphones. For a pair that works with a phone, look for listings that state low impedance, such as 16 or 32 ohms, and high sensitivity above 95 dB/mW.

When a separate amp or DAC helps

Studio headphones and some higher-end wired models may have high impedance or low sensitivity. These pairs can sound quiet when plugged directly into a phone or laptop. A dedicated headphone amplifier can supply more power, and a separate DAC can handle the conversion if the source's built-in DAC is limited.

This situation often appears when you pair headphones with an audio interface, a mixing desk, or a home recording setup. You can read more in our article on headphones for studio monitoring.

A separate DAC and amplifier can also be useful if you want to use a pair of high-impedance headphones with a computer that has a weak headphone output. Many desktop audio interfaces include a built-in headphone amplifier that can drive higher-impedance models.

Wireless headphones already include a DAC and amp

Bluetooth headphones receive a digital audio stream over the air, then convert and amplify it inside the ear cup or earbud. That is why they do not need an external DAC or amplifier. The Bluetooth radio in these headphones uses the Bluetooth Classic protocol, which is built for wireless audio streaming, as described on the Bluetooth technology website.

If you want to learn more about connection options, see our article on USB-C and headphone DACs. For wireless models, the battery life figure on the listing tells you how long the built-in amplifier can run on a charge.

How to decide for your setup

Start by checking the listing for impedance and sensitivity. If those numbers are not stated, you can often tell from the headphone's design: on-ear and over-ear models for portable use tend to be efficient, while studio and reference models may be built for higher power sources.

If you plan to plug into a phone or laptop, consider a wireless pair or a wired pair that states low impedance. If you have a home recording desk or a dedicated listening corner, a separate amp and DAC can give you more flexibility.

For a first pair, a low-impedance wired headphone or a wireless headphone is the simplest choice. For a second pair at a home desk, you might explore higher-impedance studio headphones with a separate amplifier.

What to pick for your situation

Questions

Do all headphones need an amp?

No. Many headphones are designed to work directly from a phone, laptop, or other portable source. Wireless headphones have a built-in amplifier, and many wired portable models have low impedance and high sensitivity.

How do I know if my headphones need an amp?

Check the listing for impedance in ohms and sensitivity in decibels. If the impedance is high and the sensitivity is low, the pair is likely to need more power than a phone or computer provides. If the numbers are not stated, try the headphones from your source and see if they reach a comfortable volume.

Can a phone drive high-impedance headphones?

It can drive them, but the volume may be lower than you expect. High-impedance headphones require more voltage, and a phone's amplifier is usually built to power efficient portable models.

Do wireless headphones need a DAC?

No. Wireless headphones include a DAC and amplifier inside the ear cup or earbud. They convert the digital Bluetooth signal and amplify it before it reaches the driver.

What is a good impedance for headphones used with a phone?

A low impedance, typically 16 to 32 ohms, is best for a phone or laptop. Higher impedance pairs may still work but will be quieter.

Does a separate DAC improve sound quality?

A separate DAC can handle the digital-to-analog conversion if the source's built-in DAC is limited. This article does not compare sound quality; you can read the maker's page for details on the DAC chip.

Do I need an amp for studio headphones?

Many studio headphones have higher impedance and lower sensitivity, so a dedicated headphone amplifier or audio interface is often recommended. Check the listing for impedance and sensitivity to be sure.