DAC / AmpOverreview

Apple USB-C to 3.5 mm Headphone Jack Adapter

The $9 accessory that became the measurement community's yardstick — and the argument nobody in audio has finished having.

18 sourcesUpdated
$9Typical US price

Score aggregates reviewer opinions across topics.

Check price on Amazon
As an Amazon Associate, we earn from qualifying purchases.
Apple USB-C to 3.5 mm Headphone Jack Adapter

The short version

What to know.

A nine-dollar USB-C adapter containing a genuine DAC, headphone amp and microphone input. Sources agree almost completely on three things: it is very quiet with sensitive in-ears, its output impedance is low enough not to reshape the response of low-impedance multi-driver IEMs, and nothing at the price competes. They split on how far its power goes — two measurement-literate reviewers reached opposite verdicts on 300-ohm Sennheisers — on whether better DACs are audibly better, and on whether the thin cable is a real problem. Two hardware revisions with the same name make the power question harder still: the international unit puts out about half the voltage of the American one, and the host device can cut it further.

About this product

Apple's own name for what everyone calls the Apple dongle. It is the USB-C successor to the Lightning adapter bundled with the iPhone 7, not the same part, and not the pricier USB-C to 3.5 mm Audio Cable. It ships as two hardware revisions that share a box, a name and a price: the A2049 sold in the Americas and the A2155 sold in Europe and much of the rest of the world, which is volume-limited and puts out roughly half the voltage. The current retail part numbers are MW2Q3AM/A on the US store and MW2Q3ZM/A elsewhere, which dealers still list against those same 2018 model IDs.

When Apple deleted the headphone jack, it had to sell the jack back. The USB-C to 3.5 mm Headphone Jack Adapter is a nub of white plastic on a wire barely thicker than dental floss, and inside the USB-C plug — in a space smaller than a fingernail — sit a digital-to-analogue converter, a headphone amplifier, a microphone preamp, a mono analogue-to-digital converter and the power circuitry to run all four. It costs nine dollars. It is the cheapest thing Apple sells.

It was never marketed as an audio product, and it became one anyway. In December 2018 a bench review put it ahead of both of Google's USB-C dongles and a thumb-drive-sized portable DAC many times its price, and the enthusiast internet has been arguing about it ever since — not about whether it is good for the money, which nobody disputes, but about whether anything above it is worth buying at all. Eight years on it is simultaneously the default first recommendation to a newcomer and the thing a certain kind of listener has to explain why they moved past.

A good fit for

  • In-ear listeners who want a clean, quiet, invisible source and nothing else
  • Replacing noisy onboard laptop or motherboard audio for the price of a sandwich
  • Anyone needing a mic input and in-line remote in the same plug — headsets, calls, home measurement rigs
  • Keeping spares in every bag, since it costs less than the cable it replaces

Think twice if

  • You drive 300-ohm dynamics or hard planars and want headroom rather than just volume
  • You are on an Android phone that limits the output, crackles, or refuses to see USB audio at all
  • You want above 24-bit/48 kHz, a balanced output, gain modes or volume control on the device
  • You need something that will survive being coiled around a phone every day

The reviewer consensus

Agreement &
disagreement.

3 / 7topics divide opinion
noisefeaturesergonomicsvaluepowertransparencybuild
2 Strong agreement2 Mostly agree3 Divided opinions

Common ground5

  • Very quiet with sensitive in-ears — even the hiss-prone multi-driver classics come up nearly black
  • Output impedance around 0.9 ohm or lower, so it does not reshape the response of low-impedance IEMs
  • Measures far better than the price suggests: flat response, distortion and noise below the usual limits of hearing

Points of contention4

  • Power: careful listeners reached opposite verdicts on 300-ohm Sennheisers, partly because they were on different hardware revisions
  • Transparency: audibly indistinguishable from far costlier DACs, or measurably-tiny-but-real differences that a blind test can detect
  • Build: a cable that will fail within a couple of years, or a non-issue if you are not wrapping it around a phone

A closer listen.

7 topics · 3 divided
Left: criticalRight: positiveTighter lines: more agreement

Power

Leans criticalDivided opinions
Reviewer sentiment11 supporting sources
CriticalNeutralPositive

Band: opinion spread · Dot: weighted average

Sources split, and the split is not about taste. The Americas A2049 measured 31 mW into 33 ohm; the international A2155 makes about 8.63 mW into 31 ohm before clipping, and an Android or tablet host can cut the output another 20 dB. On IEMs and efficient headphones nobody objects. On 300-ohm dynamics two careful listeners on the same revision and the same operating system reached flatly opposite verdicts about near-identical Sennheisers.

Measured

ASR measured 31 mW into 33 ohm on the US A2049, a commanding lead over both Google USB-C dongles; yuriv put its maximum at 1 Vrms on Windows and iOS. Reading the reference-audio-analyzer bench of the international A2155, ASR members put it at 8.63 mW into 31 ohm before clipping, around 0.5 V. On an Amazon Fire tablet yuriv measured a little over 0.1 Vrms — 20 dB down.

vs. listeners — The numbers are not in dispute; the threshold for enough is. Amir called the HD 650 nearly dead on the US unit, while yuriv found the near-identical HD 600 comfortable at 58 of 100 in Windows on the same 1 Vrms output. Nothing separates them but the reference they were listening against and how loud they listen — which is exactly why the aspect stays split.

Where it splits
runs out of headroom on anything demanding56%

“Switching to high-impedance 300 ohm Sennheiser HD-650 nearly killed performance.”

amirm, Audio Science Review
enough for almost anything people actually plug into it44%

“The HD600 is a walk in the park for this adapter because it draws so little current even at maximum volume.”

yuriv, Head-Fi
Link to this topic

The hardware

Specifications.

Checked

Design

Form factor
Dongle

Connection

Digital inputs
USB-C
Headphone outputs
3.5 mm
Power
USB bus power

Manufacturer-published figures, not measurements · from apple.com.

Follow the evidence

Sources 18

1–6 of 18 sources

Read with context

Limitations & method.

As of

What to keep in mind 5

  1. A read of where the reviews land as of September 2026. The adapter has been on sale unchanged since 2018, so even the oldest measurements here describe the thing in the box — but the field around it has moved a great deal.

  2. Which one you buy matters more than usual: the version sold in the Americas puts out roughly twice the voltage of the one sold in Europe and much of the rest of the world, and most published impressions never say which was on the desk.

Where to buy Product & retailer links

As an Amazon Associate, we earn from qualifying purchases.