Times when the 3.5mm headphone jack was a part of every modern smartphone are sadly long gone. Luckily, on many modern mobile phones that support audio output via their USB ports, a USB-C to 3.5mm adapter can easily help you out with using almost all types of wired headphones you might have on hand.
This guide will break down the difference between adapters with a DAC (active) and those without one (passive), so you can understand which one your device actually needs and avoid purchasing the wrong one.
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A Quick Explainer on USB-C Audio and the DAC
A DAC, or Digital-to-Analog Converter, is the chip that turns the digital data of your music file (the ones and zeros) into an electrical analog signal, so the waveform that headphone drivers actually use to produce sound. Every device that plays digital music has a DAC inside it.
The USB-C port is pretty versatile, and in terms of audio, defined by the USB Audio Device Class 3.0 (UAC3) standard, it’s capable of carrying three things: power, data, and audio. The audio signal itself can be either digital or analog.
When most phone manufacturers decided to get rid of the 3.5mm jack from most of their smartphone and tablet designs, they essentially had two choices for the USB-C port:
- Keep the phone’s high-quality internal DAC and route its analog output to the USB-C port pins. (This, as you will learn in a while, requires you to use “passive” adapters.)
- Remove the complex analog circuitry entirely (saving space/cost) and output only a digital signal via the USB-C port. (This requires you to use “active” adapters to get any sound out of the USB port at all.)
The decision made by the manufacturer is the one factor determining whether you need an adapter with a built-in DAC or not.
The Two Types of Adapters: Active (with DAC) vs. Passive (DAC-less)
Passive Adapters – The Simple Analog “Pass-Through” Without a DAC
Passive adapters are the simplest type of USB-C to 3.5mm converter you can find. It contains no DAC chip, and no additional electronics inside. It’s essentially a set of bundled wires that reroute the analog signal from the USB-C port to the 3.5mm jack – with no additional digital-to-analog signal conversion on the way.
These adapters only work if the phone supports Audio Accessory Mode (deprecated back in October 2024), meaning the phone’s internal DAC is present and routed directly to the USB-C port pins, doing the conversion work inside the device. Since it’s passive, this adapter cannot decode a digital signal and requires the phone to output a converted, usable analog signal directly.
Passive adapters are much less widespread than active ones, but they are still available on the market, and easy to confuse with their active counterparts which might look almost exactly the same at the first glance.
“(The) Audio Accessory Mode is not universally supported by smartphones, causing headphones and dongle compatibility issues.”
https://www.soundguys.com/usb-audio-explained-18563/
Active Adapters – With a DAC Built-In
Active adapters, like this one from JSAUX, have their own DAC chips and amplifiers built into their housing, despite their often small size. This adapter always asks the host device (your phone or your computer) for a digital audio stream. Once it receives the digital data, its own internal chip converts it to an analog signal and then, you’re able to hear the sound through your headphones.
Because an active adapter handles the conversion process itself, it is essentially a miniature, self-contained USB sound card, however hard it might be to believe that some of those smaller dongles can actually house a fully functional DAC chip.
These kind of adapters are the most popular ones, and can be easily used with devices that support audio output but don’t have an audio jack on board, such as the Powkiddy V90S retro handheld, or the PocketBook Verse Pro that I’ve recently reviewed, but also, with virtually any new modern smartphone.
Compatibility: Why Your Phone’s Internal DAC Might Not Be Enough
The misconception is that since your phone has a DAC chip (which is needed on all devices featuring a speaker), any type of adapters, both passive and active, should work with it. This ignores the physical wiring.
For space and cost reasons, the vast majority of modern flagship phones that ship without a headphone jack, including all current Google Pixels and newer Samsung Galaxy S models, do not route the internal DAC’s analog signal to the USB-C port. They are only able to output a digital signal, and not the analog one, and therefore, they need an adapter that features its own digital-to-analog converter on board.
While a few phones with built-in DACs can use adapters without a DAC present to pass analog audio directly (when the phone’s hardware supports analog output through the USB-C port), there aren’t many such devices on the market right now. This feature is limited to phone models that have the internal wiring and software configuration to support analog audio passthrough. Otherwise, a DAC-equipped adapter is required to convert digital audio signals to analog.
The rule of thumb is: If your phone’s design does not include a 3.5mm jack, you most likely need an active adapter with a built-in DAC. A passive adapter will simply receive a digital stream and be unable to convert it, resulting in no sound.
What’s also important here is that some USB-C ports on non-mobile devices, such as older desktop PCs, laptops, or basic USB-C hubs, might not support any kind of audio output, be it digital or analog, via any of their USB-C ports. In such cases, no adapter will work, regardless of whether it’s active or passive.
Audio Quality, Microphone Support & Other Factors
Choosing an active adapter introduces a tiny processor into the audio chain, which raises a few additional points to consider:
- Audio Quality – An active adapter’s sound quality is fully governed by its internal DAC. High-end active adapters feature high-quality chips that can actually sound better than the circuitry used in a typical budget smartphone. Conversely, some of the more affordable, lower quality active DAC on the cheaper active adapters can sometimes introduce some noticeable sound distortion and noise, or simply provide you with a flatter sound profile than the device’s native hardware could supply.
- Latency – The conversion process takes time, and this time is called latency. For a high-quality active adapter, this is often negligible (a few milliseconds), but some active adapters can introduce a slight, noticeable lag that could be important to you, for instance, if you make use of DJing apps on your tablet or smartphone.
- Microphone and Remote Support – Many active adapters you will find online are one-way devices, built only to send audio out to your headphones. If you want your headphone’s microphone or in-line remote buttons to work, you need to make sure that your chosen adapter supports it.
- Power Draw and Charging – Active adapters require a small amount of power from the host device (your phone) to run their DAC and amp chips. This can drain your phone’s battery ever so slightly faster, although the drain is in many cases comparable to using your typical set of Bluetooth buds. Some active adapters, like for instance this one from UGREEN, include a second USB-C port to enable power pass-through, allowing you to charge your phone while listening to music.
How to Tell Them Apart Before You Buy
While pricing is often the quickest indicator, it’s not foolproof, as some inexpensive active adapters with basic chips do exist, and some branded passive ones can still be overpriced.
| Feature | Passive (DAC-less) Adapter | Active (with DAC) Adapter |
|---|---|---|
| Required from Host | Analog signal sent through the USB-C port (Audio Accessory Mode) | Digital audio signal sent through the USB-C port |
| How It Works | Physical wire routing (pass-through) | Digital-to-Analog Conversion |
| Microphone / Buttons Support | Depends entirely on the phone’s wiring. Often not present. | Not guaranteed. Look for this feature in the product description. |
| Typical Cost | Low (mostly around ~$5) | Low-Mid (~$5 and up depending on the DAC chip quality) |
| Availability | Harder to find if you’re looking specifically for them, but still quite commonly sold online. | Very common, and available both in cheaper and more expensive variants. Always look for the “DAC” keyword in the listing. |
The Final Verdict: Which USB-C Adapter Should You Get?
For almost every modern device, that is, your Samsung, Google Pixel, iPad, or any laptop from the past few years, the choice is clear: get an active adapter with a built-in DAC, that explicitly supports microphones and remote controls.
Just keep in mind that active adapters are still just one part of the equation. If you encounter any issues like persistent static or audio dropouts, it could still be the fault of a low-quality implementation of the DAC chip itself.
This is often the case with cheaper, worse quality adapters. That’s why, it might just be wise to get a better quality one to begin with, that you can use with all your devices without any problems. Starting with a basic adapter like this with a good price-to-quality ratio, is most often the best choice.
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