If you are asking whether you need a DAC or amp for the Audio-Technica ATH-M50x, the answer is usually no. Its 38 ohm impedance and 99 dB/mW sensitivity work out to just 0.69 V RMS and 12.6 mW for 110 dB peaks. A competent phone dongle, laptop jack or audio interface can supply that. Add a DAC/amp when the existing jack is noisy, hums, distorts, will not play loudly enough, or does not exist.
This conclusion comes from manufacturer specifications and published measurements. AmperHeads has not bench-tested, owned or auditioned the products discussed here. The full ATH-M50x review covers the headphone itself. This article stays with the narrower source question.
The ATH-M50x voltage and power math
Audio-Technica specifies 38 ohms and 99 dB/mW . Using the requested 110 dB peak target:
power = 10^((110 - 99) / 10) = 12.59 mW
voltage = sqrt(0.01259 W x 38 ohms) = 0.69 V RMS
current = 0.69 V / 38 ohms = 18.2 mA RMS
| Peak SPL target | Power | Voltage | Current |
|---|---|---|---|
| 100 dB | 1.26 mW | 0.22 V RMS | 5.8 mA |
| 105 dB | 3.98 mW | 0.39 V RMS | 10.2 mA |
| 110 dB | 12.59 mW | 0.69 V RMS | 18.2 mA |
That 110 dB figure is a brief peak allowance, not a sensible continuous listening level. It gives a source room for quiet masters and momentary musical peaks. Audio-Technica’s 1,600 mW maximum input specification is a ceiling, not the amount the headphone needs.
The published number also holds up well against independent data. Reference Audio Analyzer measured 100.3 dB/mW average sensitivity and 37.1 ohms average impedance. Its measured impedance stayed between 35.7 and 40.6 ohms from 40 Hz to 15 kHz. The manufacturer-based calculation is therefore slightly conservative. You can run other targets through our headphone power calculator .
Output impedance matters too. The one-eighth guideline says the source should stay below 38 / 8, or 4.75 ohms. Sonarworks explains the one-eighth rule as protection against frequency response changes caused by the interaction of source and headphone impedance.
Phones, laptops, dongles and audio interfaces
There is no single output specification for every phone or laptop. Check the exact device because category labels tell too little. These verified examples show how modest the ATH-M50x requirement is.
| Source | Published or measured output | ATH-M50x verdict |
|---|---|---|
| Apple USB-C adapter, Americas version | 31 mW into 33 ohms and 0.9 ohm output impedance, measured by Audio Science Review | Enough power, passes the 4.75 ohm guideline |
| Apple A2155 USB-C adapter | 0.5 V maximum and about 0.3 ohm output impedance, measured by Reference Audio Analyzer | About 107 dB by the rated sensitivity, short of the 110 dB target |
| Compatible recent Mac headphone jack | Up to 1.25 V RMS below 150 ohms, according to Apple | More than the required 0.69 V |
| Focusrite Scarlett 2i2 4th Gen | 32 mW into 33 ohms and 50 ohm output impedance, according to Focusrite | Enough power, misses the impedance guideline |
| FiiO KA3, 3.5 mm output | 130 mW into 32 ohms and below 0.5 ohm output impedance, according to FiiO | Far more power than required |
The international A2155 Apple adapter still reaches a loud theoretical peak, although it does not meet this article’s conservative 0.69 V target. The Scarlett example is useful because power and output impedance answer different questions. Its 32 mW rating clears the loudness target. Its 50 ohm output is far above 4.75 ohms.
The ATH-M50x has an unusually flat impedance curve, however, and Reference Audio Analyzer’s compatibility model shows only about 0.5 to 0.6 dB of response change with a 50 ohm source. This is a small model-specific exception. Keep applying the impedance guideline to other headphones.
A phone with a 3.5 mm jack gets the same practical test. If it reaches your preferred level with spare volume, stays clean on bass peaks and has no background noise, it already does the job. A phone without a jack needs a dongle for connection. That says nothing about whether the headphone is difficult to drive.
When a DAC changes something
A DAC converts the digital audio stream into an analog signal. Any phone, laptop or interface with a working analog headphone output already contains one. A USB dongle contains a DAC plus a small headphone amplifier. Our plain-English DAC explainer covers that signal path in more detail.
An external DAC can make a practical difference when a laptop jack produces hiss during quiet passages, buzz that changes with charger or computer activity, audible distortion, or poor channel balance near the bottom of its volume range. Moving conversion and amplification into a USB adapter may bypass a noisy internal analog stage. It cannot guarantee a cure for a ground loop, and it cannot repair noise already present in the recording.
A cleaner DAC will not reshape the ATH-M50x into a different headphone when the original source is already quiet, flat and powerful enough. Digital resolution claims do not cancel the headphone’s own frequency response. A DAC with line outputs also cannot drive the ATH-M50x by itself. It needs a headphone amplifier, whether that amplifier is in the same box or a separate one.
What is worth buying
For a USB-C phone or a noisy laptop jack, the Apple USB-C to 3.5 mm adapter is the sensible first move. Apple lists it at about $9 in October 2026 . The Americas unit measured above the ATH-M50x requirement and its low output impedance is a clean electrical match. The international A2155 measurement above shows less headroom, so confirm the regional model if the 110 dB peak target matters.
See today's price for the Apple USB-C to 3.5 mm Headphone Jack Adapter on Amazon ↗The FiiO KA3 is electrically ample, but buying it only for this headphone makes little sense. FiiO still hosts its specification page, yet the KA3 was absent from the company’s current USB dongle navigation when checked in October 2026. Current first-party availability and a current list price could not be confirmed. Consider one only if you already have it or also plan to power a more demanding headphone.
A desktop amp is unnecessary for normal ATH-M50x listening. It can still be useful for a physical volume knob, multiple inputs, or future headphones. The model-specific amp pairing guide covers those choices without repeating them here, while the broader amp checklist helps with another headphone.
A quick decision test
Play a quiet, well-recorded track with EQ disabled. If your normal level sits comfortably below maximum volume and peaks remain clean, you have enough voltage and current.
Pause playback at the same volume. Hiss, hum or computer-related buzz gives you a reason to try an external USB adapter. Silence gives you no problem to solve.
If possible, compare the old jack and the dongle at closely matched loudness. A small level difference can be mistaken for a quality difference. Keep the simpler source when both are clean and equally loud.
For the Audio-Technica ATH-M50x, a clean 0.7 V source with less than 4.75 ohms output impedance is the useful target. Phones, laptops, dongles and interfaces often meet it. Buy a DAC or amp only when it fixes an identified source problem.