An AES/EBU cable and a microphone cable both have XLR connectors, so it is tempting to use whatever is in the drawer. On a short run it may even work. Here is why a proper 110 ohm cable is still the right choice for digital audio.
What AES/EBU Asks For
AES/EBU sends digital audio as a fast stream of pulses down a balanced line. The standard calls for a cable with a characteristic impedance of 110 ohms, so the cable matches the outputs and inputs on each end.
What Goes Wrong With a Mic Cable
A microphone cable is not built to a controlled impedance. When the impedance does not match, part of the signal reflects back along the cable. The pulses lose their clean edges, which shows up as timing errors, or jitter, and on longer runs as clicks and dropouts.
On a very short patch the effect may be too small to notice. As the run gets longer, or the sample rate goes up, the problems get more likely.
The Simple Rule
- Digital audio over XLR: Use a true 110 ohm AES/EBU cable.
- Analog audio: Use a microphone or line cable. A 110 ohm cable works here too.
The Other Way Around
A 110 ohm cable is fully balanced, so it carries analog signals without trouble. Read can you use an AES/EBU cable for analog audio?
Ghost Analog/Digital
Ghost Analog/Digital is a true 110 ohm cable with nickel-plated copper conductors and both a foil and a braided shield. Its dark purple jacket makes digital runs easy to spot in a shared loom.