To use wired IEMs with your phone when it has no headphone jack, you have three choices: a cable with a DAC built into the plug, a separate USB-C dongle DAC, or a Bluetooth adapter that replaces the cable. A DAC cable is the tidiest. A dongle is the most flexible. Bluetooth is the most convenient, but it adds a battery and depends on your phone's codecs.
This guide is for anyone who owns, or is buying, wired in-ear monitors and wants to use IEMs with your phone every day. You'll learn what a DAC does, which plug an iPhone or Android phone needs, how much power common dongles deliver, and when Bluetooth makes sense. We also show which Null Audio cables fit each route.
Key takeaways
- iPhone 15 and later use USB-C; iPhone 5 to iPhone 14 use Lightning, so the plug you need depends on your model.
- Apple's USB-C to 3.5 mm adapter measured about 0.5 Vrms maximum, enough for many sensitive IEMs but with no balanced output.
- Dongle DACs such as the FiiO KA13 offer a 4.4 mm balanced output rated at 550 mW or more into 32 ohms.
- Null Audio's Capri USB-C cable puts a DAC in the plug from USD 39, and Ethos Ultra includes 3.5 mm, 4.4 mm and USB-C DAC plugs in the box.
- Nyx+ is a Bluetooth 5.3 IEM cable with LDAC, aptX and AAC support and up to 20 hours of playback.
Why do IEMs with your phone need a DAC?
A DAC (digital-to-analogue converter) is the chip that turns digital music into the electrical signal your IEMs play. Phones with a headphone jack have one inside. Most current phones don't, so the DAC has to live somewhere else: in the cable's plug, in a dongle, or in a Bluetooth receiver.
A headphone amplifier is the stage after the DAC that drives the earphones. In small devices the two usually come together. Their quality, power and output impedance shape what you hear.
Output impedance is the source's internal resistance. It forms a voltage divider with your IEMs, and multi-driver IEMs change impedance with frequency. A common rule of thumb is to keep output impedance at or below 1/8 of the earphone's impedance (Headphones.com). We cover this in Do IEM upgrade cables make a difference?
The three options compared
Each route trades simplicity, flexibility and convenience differently. The table sums it up.
| DAC cable (USB-C or Lightning plug) | Dongle DAC + normal cable | Bluetooth adapter | |
|---|---|---|---|
| What you carry | One cable | Cable plus a small dongle | One wireless cable, plus a charger |
| Wires to the phone | Yes | Yes | No |
| Battery | None; powered by the phone | None; powered by the phone | Needs charging |
| Sound limited by | The DAC chip in the plug | The dongle you choose | The Bluetooth codec and the adapter's amplifier |
| Works with a computer or player too | Computer yes; player only with a second 3.5 mm or 4.4 mm plug | Yes, use the cable on its own | Any Bluetooth source |
| Best for | Simplicity, commuting | People who also use a DAP or desktop amp | Gym, travel, calls |
Option 1: a cable with the DAC in the plug
A USB-C or Lightning plug with its own DAC and amplifier turns your phone into a source with nothing else to carry. It is the simplest way to use IEMs on the move.
USB-C and Lightning DAC plugs on our cables
Our configurable cables can be built with a USB-C DAC plug, using either the ALC5686 or the ESS9280C chip. A Lightning plug is also available for older iPhones and iPads. A microphone option is offered on selected cables.
Capri USB-C
Capri USB-C starts at USD 39. It supports 24-bit playback at up to 192 kHz, with call controls and 2-pin or MMCX connectors. It is tuned for sensitive IEMs. If your IEMs are above 18 ohms with sensitivity below 105 dB, you may need to set the volume higher than usual.
Capri Balanced
Capri Balanced starts at USD 49. It puts a balanced DAC and amplifier in the cable, rated at 128 mW into 16 ohms. Output impedance is below 1 ohm and THD+N below 0.01%. Its listed frequency response is 5 Hz to 45 kHz.
Ethos Ultra
Ethos Ultra starts at USD 89. Its player end is detachable, and 3.5 mm, 4.4 mm balanced and USB-C DAC plugs all come in the box. The same cable works with your phone, a dongle or a player.
Option 2: a dongle DAC with a normal cable
A dongle DAC is a small USB-C adapter that sits between the phone and a cable with a standard 3.5 mm or 4.4 mm plug. Its advantage is flexibility. The same cable plugs straight into a portable player or desktop amp later.
Dongles vary widely in output. Apple's USB-C to 3.5 mm adapter has a 3.5 mm output only. The EU model A2155 measured about 0.5 Vrms maximum with 0.3 ohms output impedance (Reference Audio Analyzer). Many dongles add a balanced output with more voltage:
- FiiO KA13: 170 mW or more from 3.5 mm and 550 mW or more from 4.4 mm, both at 32 ohms (FiiO).
- Moondrop Dawn Pro: 2 Vrms single-ended and 4 Vrms balanced (Moondrop).
- iBasso DC04 Pro: 2 Vrms single-ended and 3 Vrms balanced.
Balanced output gives each channel its own return wire, and a bridged amplifier roughly doubles the voltage swing. Choose your cable's plug to match the dongle. Our player plug guide lists popular outputs, and 3.5 mm, 2.5 mm or 4.4 mm balanced? explains the difference.
Option 3: a Bluetooth adapter for your IEMs
A Bluetooth IEM cable is a wireless receiver and amplifier that clips onto your IEMs in place of the wire. It keeps your IEMs and their sound signature but removes the cable to the phone.
Nyx+ starts at USD 89. It is our Bluetooth 5.3 IEM cable:
- LDAC, aptX, aptX HD, aptX Adaptive, AAC and SBC codecs.
- A dedicated Class D headphone amplifier.
- Up to 20 hours of playback and up to 15 m of range.
- USB-C charging, about 25 minutes to full.
- Calls with cVc noise cancellation.
- 58 cm long and 15 g in weight.
Most Bluetooth codecs use lossy compression. For critical listening at home, a wired connection is still the reference.
Does it matter if you use an iPhone or Android?
Yes, for both the plug and the codec. According to Apple, iPhone 15 and later have USB-C, while iPhone 5 to iPhone 14 use Lightning. A USB-C DAC plug suits newer iPhones and most Android phones. Older iPhones need a Lightning plug.
Over Bluetooth, iPhones use AAC. LDAC and aptX depend on the Android phone, so check your phone's specifications before you rely on them.
Which way to use IEMs with your phone suits you?
Pick the route that matches how you listen.
- Phone only, minimal kit: a USB-C DAC cable or Capri.
- Phone now, a player or desktop amp later: a cable with a 3.5 mm or 4.4 mm plug plus a dongle, or Ethos Ultra with its swappable plugs.
- Exercise, travel, lots of calls: Nyx+.
Whichever you choose, the earphone end must match your IEM. Capri comes with 2-pin or MMCX. Our configurable cables, including their USB-C and Lightning plugs, are built with whichever connector your IEM uses. Our IEM cable connector guide explains the differences. If you're also weighing conductor materials, see copper vs silver IEM cables.
Get a cable built for your phone
Not sure which connector your IEM uses? Check Find My Cable, which lists over 400 models. For Nyx+, ask us about your IEM's connector before you order.
Every cable is built to order in Singapore and covered by a 1-year warranty. Shipping is free worldwide from USD 250 by FedEx. Browse all IEM and headphone cables to get started.
Frequently asked questions
Can I use wired IEMs with an iPhone?
Yes. iPhone 15 and later have USB-C, so they work with a USB-C DAC cable or dongle. iPhone 5 to iPhone 14 use Lightning and need a Lightning DAC plug or adapter. You can also go wireless with a Bluetooth IEM cable, which uses AAC on iPhone.
Is Apple's USB-C to 3.5 mm adapter good enough for IEMs?
The EU model A2155 measured about 0.5 Vrms maximum with 0.3 ohms output impedance. That low output impedance suits many sensitive IEMs. It has no balanced output, so if you want 4.4 mm balanced you need a different dongle or a DAC cable.
Do I need a balanced dongle for my IEMs?
Not always. Balanced output gives each channel its own return wire and roughly doubles the voltage swing, which helps harder-to-drive earphones. Many sensitive IEMs play loudly enough from a single-ended 3.5 mm output.
Does Bluetooth sound worse than a wired DAC?
Most Bluetooth codecs use lossy compression, so for critical listening at home a wired connection remains the reference. Which codec you get depends on your phone.
Which Bluetooth codecs does an iPhone support?
iPhones use AAC over Bluetooth. LDAC and aptX are available only on Android phones that support them. A Bluetooth IEM cable such as Nyx+ supports AAC, SBC, LDAC and the aptX family, so it works with both.
Can one IEM cable work with my phone and my DAP?
Yes, if its player end is detachable. Null Audio's Ethos Ultra comes with 3.5 mm, 4.4 mm balanced and USB-C DAC plugs in the box. You can also use a cable with a standard plug and add a USB-C dongle for your phone.
Sources
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