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Guide

IEM cable connectors

The connector on your earphone decides which cable fits. Check the socket, not the brand: one maker can use different connectors across its range, and similar-looking sockets can differ in recess depth or keying.

Find my IEM

Common connectors

What each option is

2-pin 0.78 mm (standard)

Two 0.78 mm pins. Our most widely compatible plug: it fits both recessed and flat 2-pin sockets, so it suits most 2-pin earphones. Match the marked side of the plug to the socket.

Null AudioNull Audio
Flat 2-pin

For earphones with a flat 2-pin socket. If you are not sure whether your socket is flat or recessed, choose standard 2-pin, which fits both.

Null AudioNull Audio
UE / UM / qdc 2-pin

2-pin with a raised plug housing, for UE, Unique Melody and qdc earphones with an extended socket. Choose UE/UM/QDC 2PIN Legacy.

Null AudioNull Audio
JH 4-pin and 7-pin

JH Audio’s own connectors with the bass adjuster on the cable. Choose JH w Bass Control for 4-pin or JH 7-pin for 7-pin; both work like JH Audio’s own cable.

Null AudioNull Audio
MMCX

Coaxial snap-on connector that usually rotates once seated. Some earphones recess or key the socket, so a standard MMCX plug may not fit them: see the model guides.

General referenceGeneral reference
A2DC

Audio-Technica's connector.

General referenceGeneral reference
IPX and T2

IPX is used on current Ultimate Ears custom IEMs. Our IPX plug also fits T2 sockets, such as Westone MACH and Pro X and Ultimate Ears UE 150/250/350, so choose IPX for those too.

Null AudioNull Audio; UE cable pages for IPX use
Not supported

FiR RCX. 0.75 mm 2-pin (for example JH Billie Jean) is supported: choose KZ / 64 Audio 0.75 Flat 2PIN. 64 Audio customs are supported too: they have an IPX or a 2-pin socket, so choose IPX or Flat 2-pin to match.

Null AudioNull Audio

Null Audio

FlexiPlug

FlexiPlug is our interchangeable connection system. It lets you change the earphone-side connector on one cable. Current tips: 2-pin, IE300, A2DC, IPX, Pentaconn Ear and qdc 2-pin.

Model-specific plugs

Brand and model guides

Detailed guides for brands and models with their own connectors or common questions.

HIFIMAN Sundara

Choose Dual 3.5 mm.

 Published review Focal Clear, Clear MG

Choose Dual 3.5 mm.

 Retailer listing Sony headphones

Z1R, Z7: Dual 3.5 mm. 1A, M1ST, MV1, M1: Single 3.5 mm.

 Retailer listing Moondrop Chu 2

Choose Standard 2-pin.

 Manufacturer Shure SE215

Choose MMCX.

 Manufacturer Truthear Hexa

Choose Standard 2-pin.

 Manufacturer KZ ZS10 Pro, ZSN Pro X, EDX Pro, Castor

Choose KZ C-pin 0.75 2PIN, or the flat plug for flat sockets.

 Null Audio Sennheiser HD 600 / HD 650

Choose Sennheiser HD600/650.

 Manufacturer Sennheiser HD 560S / HD 5x9

Choose Sennheiser HD 5x9.

 Manufacturer Sennheiser HD 800 / HD 800 S

Choose Sennheiser HD800.

 Manufacturer LETSHUOER S12, Ember, Astralis

Choose Standard 2-pin.

 Manufacturer 7Hz Salnotes Zero, Zero:2

Choose Standard 2-pin.

 Retailer listing Truthear Gate, Hola

Choose Standard 2-pin.

 Manufacturer Moondrop Starfield, Starfield II

Choose Standard 2-pin.

 Manufacturer Sennheiser IE 200 / IE 300 / IE 600 / IE 900

Choose IE300/600/900. Recessed MMCX socket.

 Manufacturer Sennheiser IE 40 PRO / IE 400 PRO / IE 500 PRO / IE 80

Each has its own option, not standard MMCX.

 Null Audio configurator Sony IER-Z1R / IER-M9 / IER-M7 / XBA

IER-Z1R: choose Sony IER-Z1R. IER-M7: MMCX.

 Null Audio configurator Etymotic ER4SR / ER4XR / ER4P / ER2

ER4SR/XR: keyed MMCX. Older ER4P/B/S: own option.

 Manufacturer Shure SE846 / SE535 / SE215 / AONIC

Standard MMCX.

 Manufacturer 64 Audio

Universals: Flat 2-pin. Aspire: IPX. Customs: IPX or Flat 2-pin, matching your socket.

 Manufacturer JH Audio

4-pin: JH w Bass Control. 7-pin: JH 7-pin.

 Manufacturer Westone MACH / Pro X

T2 socket: choose IPX. Older W and UM Pro: MMCX.

 Null Audio Ultimate Ears (UE)

Current customs and UE 150–350: IPX. Older 2-pin and SL: UE/UM/QDC 2PIN Legacy.

 Manufacturer Campfire Audio

Most models: MMCX. Andromeda 10, Chimera: 2-pin.

 Manufacturer Audio-Technica

Choose A2DC. IM series: plug on request.

 Manufacturer AAW (Advanced AcousticWerkes)

Choose Standard 2-pin. Nebula One: fixed cable.

 Null Audio Moondrop

Choose Standard 2-pin. Original CHU: fixed cable.

 Manufacturer qdc and CCA

KZ, CCA: KZ C-pin 0.75 2PIN or KZ / 64 Audio 0.75 Flat 2PIN. qdc: UE/UM/QDC 2PIN Legacy.

 Null Audio Truthear, Kiwi Ears, Simgot and more

Most: Standard 2-pin. Some: MMCX.

 Published review Empire Ears

Choose Standard 2-pin.

 Published review Vision Ears

Choose Standard 2-pin.

 Published review Noble, UM, FiR, Softears, Symphonium, Elysian

Most: Standard 2-pin. Elysian: FlexiPlug.

 Published review JOMO Audio

Choose Standard 2-pin.

 Null Audio Dunu

Most: MMCX. Some: 2-pin.

 Retailer listing FiiO

Choose MMCX.

 Manufacturer final

Choose MMCX.

 Manufacturer beyerdynamic

DT PRO: Mini XLR 3PIN. T1, T5: Beyer T1/T5P.

 Manufacturer HIFIMAN

Most: Dual 3.5 mm. HE1000, early HE400i: Dual 2.5 mm.

 Published review Audeze

Choose Mini XLR 4PIN.

 Manufacturer Focal

Most: Dual 3.5 mm. Utopia: Focal Utopia.

 Retailer listing 4.4 mm balanced cables

Every cable with a 4.4 mm plug, and which FiiO players take one.

 2-pin IEM cables

0.78 mm, recessed or flat: Standard 2-pin.

 Null Audio MMCX IEM cables

Shure, Campfire, FiiO, final, Dunu: MMCX.

 Null Audio configurator IPX IEM cables

64 Audio Aspire, UE customs, Westone T2: IPX.

 Null Audio KZ

Raised socket: KZ C-pin 0.75 2PIN. Flat: KZ / 64 Audio 0.75 Flat 2PIN.

 Null Audio Extension cables

3.5 mm and 4.4 mm extensions, or a longer cable up to 3 m.

 USB-C IEM cables

A DAC in the plug, for phones and laptops. Lightning too.

 IEMs for gaming

A mic cable turns your IEMs into a headset.

 Interconnect cables

XLR, RCA, 3.5 mm, 4.4 mm and USB, 10 cm to 2 m.

 Visit our Singapore studio

76 Playfair Road. Auditions, ear impressions, pickup.
Sony Walkman

WM1, ZX, DMP-Z1: 4.4 mm. A series: 3.5 mm.

 Manufacturer AKG N40 / N5005 / K712

N40, N5005: IE300/600/900. K712, K702, K371: Mini XLR 3PIN.

 Null Audio 4.4 mm balanced vs 3.5 mm

Is balanced worth it? Power, output impedance and when it matters.

 Best cables for Sennheiser IE 600

Our picks for IE 600, IE 300 and IE 900.

 Best IEM cables under $100 / $200

Our picks, and every cable in each band compared.

 2-pin vs MMCX vs IPX

How they compare in use, what wears and how to tell them apart.

Sources

Sources

  1. Null Audio configurator, Headphone connection Connector options listed on this page. Snapshot 16 Oct 2026.
  2. Pentaconn — Connector reference 0.78 mm 2-pin pin geometry, as general background.

Prepared 17 Oct 2026. Not yet reviewed by Null Audio.