Optical vs. Coaxial Digital Cables: Which Should You Use?

Quick answer

Use optical (Toslink) when you need electrical isolation or a long run without hum, and use coaxial when you want a simple, robust connection for short runs in a normal home system. Both carry the same digital audio data, so the right choice depends on your ports, cable length, and whether ground noise is a problem.

How optical and coaxial actually differ

Optical cables send light through a fiber conductor, so no electrical current travels between your source and your DAC. That means ground loops and radio-frequency noise from a TV, computer, or game console cannot ride along the cable. The trade-off is that light disperses as it travels, and a poorly made fiber can let delayed signal arrive late enough to confuse the receiving chip. AudioQuest addresses this in the Cinnamon Optical by using a lowest-dispersion, highest-purity fiber conductor so the light arrives with less smearing.

Coaxial cables send the digital signal as an electrical voltage through a metal conductor with a shield around it. They are mechanically simple, tolerant of being bent and routed, and usually cheaper per foot for a given build quality. The trade-off is that the shield has to do real work: if it is inadequate, radio-frequency noise and ground-borne hum can couple into the signal path. A purpose-built coax like the AudioQuest Jack Russell RCA manages distortion and radio-frequency noise at every stage, from conductor design to termination.

When optical is the better call

Optical wins when electrical isolation matters more than anything else. If your source is a TV, a desktop computer, or a game console that shares a power strip with your audio gear, optical breaks the ground connection and often removes a hum or buzz that no amount of cable swapping fixes. It is also the safer choice for long runs, because light does not pick up interference the way an electrical signal can.

The catch is that optical is less forgiving of tight bends and cheap fiber. If you coil it sharply or use a thin, low-quality cable, you can get dropouts or a signal that the DAC struggles to lock onto. Stick to a cable with a proper fiber conductor, keep bends gentle, and keep the run under the length you actually need.

When coaxial is the better call

Coaxial is the practical default for short runs between a streamer, CD transport, or DAC and an amplifier. It is robust, easy to route, and the connectors stay put. If your gear has both optical and coaxial outputs, coaxial is often the simpler choice for a tidy rack because the cable can be bent and tied without worrying about light loss.

The trade-off is noise. In a system with a lot of digital gear on the same circuit, a coax cable can act as a path for ground noise. A cable with proper shielding and controlled conductor geometry, like the Jack Russell RCA, reduces that risk, but it cannot eliminate a ground loop that originates elsewhere in the system. If you hear hum only with coax connected, that is your clue to try optical.

What about power and DAC choices?

The digital cable is only one link. If your DAC is powered from a noisy wall supply, a power cable like the AudioQuest NRG-X3 can reduce distortion caused by grain boundaries and strand interaction, which in turn makes the digital input stage's job easier. This is not a substitute for choosing the right digital cable, but it is a sensible companion upgrade if you are already chasing a lower noise floor.

Similarly, if you are feeding a computer or phone into your system, a DAC like the AudioQuest DragonFly Copper handles the conversion and headphone amplification in one small package. It accepts a digital input and outputs analog, so the optical vs coaxial decision applies to whatever feeds it, not to the DragonFly itself.

Trade-offs at a glance

• Optical isolation vs. fiber fragility: Optical breaks ground loops and ignores electrical noise, but the fiber is less tolerant of tight bends and cheap construction. Choose optical if hum disappears when you unplug coax; handle it gently and keep runs reasonable.
• Coaxial simplicity vs. shield dependence: Coax is robust, bendable, and easy to route, but its performance depends on shielding and termination quality. Choose coax for short, tidy runs in a system without ground noise; upgrade the cable if you hear RF hash.
• Length vs. signal integrity: Optical handles long runs better than coax in most home setups, but both have practical limits before the receiver struggles. Keep both cables as short as the layout allows; if you must go long, optical is usually the safer bet.

Products that fit this comparison

• Cinnamon Optical Factory Certified Refurbished: Lowest-dispersion, highest-purity fiber conductor designed to reduce delayed light arrival that can prevent proper decoding. If you choose optical for isolation, this addresses the main weakness of cheap Toslink cables: signal smearing that causes dropouts or failure to lock.
• Jack Russell RCA: Purpose-built for clean, low-distortion signal transfer, controlling distortion and managing radio-frequency noise at every stage of the signal path. A coax cable is only as good as its shielding and termination. This one is designed to keep noise out on short, normal-length runs.
• NRG-X3 Factory Certified Refurbished: Long-Grain Copper minimizes distortion caused by grain boundaries, and semi-solid concentric conductors reduce strand-interaction distortion. If you hear hum or grain with coax and suspect the power side, this is a logical next step after you have confirmed the digital cable itself is not the culprit.

Which should you use?

Best for

• TV, computer, or game console feeding a DAC in a system with hum or ground noise
• Long cable runs where electrical interference is a concern
• Listeners who want electrical isolation between source and DAC

Not for

• Very tight rack spaces where the fiber would be bent sharply
• Systems where the source and DAC already share a clean, low-noise ground
• Anyone who needs the absolute lowest-cost connection for a short run