How to Use a Headphone Amplifier
Updated Nov 13, 2026 · By 
Jonah Mercer · Editorial policy
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A headphone amplifier sits between a source and headphones: plug the source into its input, plug the headphones into its output, and set the volume on the amp. The Fosi Audio K7 takes USB-C, optical, coaxial or Bluetooth from a computer or console, while the Pyle PHA40, FIFINE N6 and Mackie HM-4 split one source output to four headphones.
Connect the source to the input
Start with the source turned down or off. The Fosi Audio K7 takes USB-C, optical, coaxial or Bluetooth from a computer or console, and the Pyle PHA40 and FIFINE N6 take a 1/4-inch TRS cable from a mixer output. The Mackie HM-4 drives four headphones from any source with a 1/4-inch or 1/8-inch output. Plug the cable into the input jack, not the headphone output.
Plug in the headphones and set the volume low
Turn the volume knob all the way down before you plug the headphones in. The Fosi Audio K7 has 4.4mm balanced and 3.5mm outputs for headphones, the Pyle PHA40 and FIFINE N6 have 1/4-inch TRS headphone outputs, and the Mackie HM-4 has four 6.35mm outputs. Push the plug in all the way, then raise the volume slowly to the level you want.
Pick the input and the output
The Fosi Audio K7 switches between headphones and speakers or four input sources with its dual control knobs and five shortcut buttons, and its display shows the status. The Pyle PHA40, FIFINE N6 and Mackie HM-4 send one source to four headphone outputs, so each listener plugs into a separate output. Check that the source is playing before you change any setting.
Set the volume for each listener
Each listener sets a volume that suits them. The Pyle PHA40 has an independent volume knob for each of its four outputs, the FIFINE N6 has a separate volume knob for each output, and the Mackie HM-4 has level control per listener. On the Fosi Audio K7, use the dual control knobs and the built-in EQ or Bypass mode to shape the sound for music or gaming.
Check the power and the cables
Plug the power supply in before you switch the amp on. The Fosi Audio K7 comes with a 12V power supply, and the FIFINE N6 comes with a 12V DC power adapter and a light that shows the power is on. The FIFINE N6 needs a 1/4-inch TRS cable for the input and output, and that cable is not included in the package.
What you need
Fosi Audio K7 DAC Headphone Amp
A desktop DAC headphone amplifier with USB-C, optical, coaxial and Bluetooth inputs, 4.4mm balanced and 3.5mm outputs, and up to 2100mW of power for headphones.
- Built-in DAC
- Balanced output
- USB connection
- 24-month warranty stated
Pyle 4-Channel Portable Stereo Headphone Amplifier
A 4-channel splitter that powers up to four pairs of headphones at once, with an independent volume knob for each listener.
- Balanced output
- 1-year warranty stated
FIFINE N6 4 Channels Metal Stereo Headphone
A 4-channel metal splitter with a separate volume knob for each of four outputs, a 1/4-inch TRS input and a 12V DC power adapter.
- Balanced output
- One year warranty stated
Mackie HM-4 Headphone Amplifier
A compact 4-channel splitter that drives four headphones from any source with a 1/4-inch or 1/8-inch output, with level control per listener.
- 1-year warranty stated
These come from our ranked list Best Headphone Amp, which compares them spec by spec.
Frequently asked questions
Do headphones need a headphone amplifier?
It depends on the source. A DAC amp such as the Fosi Audio K7 takes a USB-C, optical, coaxial or Bluetooth signal and drives headphones with up to 2100mW of power, while a phone or laptop output drives headphones on its own. If the sound is too quiet, an amplifier adds power between the source and the headphones.
Can four people listen at the same time?
Yes, with a 4-channel amp. The Pyle PHA40 powers up to four pairs of headphones at once, the FIFINE N6 shares one stereo source across four outputs, and the Mackie HM-4 drives four headphones from any source. Each listener sets a volume with a separate knob or level control.
What cable do I need for the input?
It depends on the amp. The Fosi Audio K7 takes USB-C, optical, coaxial or Bluetooth, and the Pyle PHA40 and FIFINE N6 take a 1/4-inch TRS cable from a mixer output. The FIFINE N6 needs a 1/4-inch TRS cable for the input and output, and that cable is not included.
Can I switch between headphones and speakers?
Yes, on the Fosi Audio K7. Its dual control knobs and five shortcut buttons switch between headphones and speakers or four input sources, and the display shows the status. The Pyle PHA40, FIFINE N6 and Mackie HM-4 are headphone splitters, so they send one source to headphones only.
Ranked headphone amps lists
More how-to guides
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