XLR (AES3, 110 Ω) pinout
AES/EBU (AES3) XLR Wiring
AES/EBU digital audio uses the same XLR pin assignments as analog (pin 1 shield, pin 2 data+, pin 3 data−) but is a 110 ohm transmission line carrying a 2-channel digital stream. The connector is identical; the cable is not, and that difference is the entire page.
| Pin | Signal | Notes |
|---|---|---|
| 1 | Shield | Cable shield and reference. |
| 2 | Data + | Non-inverted leg of the balanced digital pair. |
| 3 | Data − | Inverted leg. The data encoding is polarity-insensitive, but wire it correctly anyway. |
What it’s used for
AES3 carries two channels of digital audio between consoles, processors, amplifiers, and broadcast gear: one cable, two channels, embedded clock. It looks exactly like a mic line on the patch, which is why AES paths get labeled loudly.
The 75 ohm unbalanced variant (AES-3id) rides BNC and coax for long broadcast runs; impedance-matching baluns convert between the two worlds.
Wiring & termination notes
- Use 110 ohm AES/digital cable for runs of consequence. Analog mic cable has roughly half the impedance and smears the signal edges; short patches usually survive, long runs produce clicks, sparkle, or silence.
- The receiver recovers its clock from the stream, so cable-induced jitter is the failure currency; quality cable and clean terminations are the whole defense.
- AES signal levels are volts-scale digital, not mic level: never patch an AES output into a mic preamp looking for audio.
- Sample-rate mismatches are configuration, not wiring: a device receiving 96 kHz AES it cannot lock produces exactly the same silence as a broken cable.
Frequently asked questions
Can I use a regular XLR mic cable for AES/EBU?
For a short patch, usually yes. For long runs, no: AES3 specifies 110 ohm cable, and microphone cable’s wrong impedance causes reflections that corrupt the data. The connector fits; the physics does not.
How far can AES/EBU run?
On proper 110 ohm cable, around 100 meters is routine at standard rates; the standard contemplates more with quality cable. Beyond that, use the 75 ohm coax variant, fiber, or an audio network.