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Optical TOSLINK and digital coaxial are two ways to carry S/PDIF audio: optical sends pulses of light through fiber, while coaxial carries an electrical digital signal over an RCA-style connection. In most setups, choose the connection that matches the source’s output and the receiver’s input. Both share S/PDIF’s format limits; neither carries high-resolution lossless formats such as Dolby TrueHD or DTS-HD Master Audio. If both devices support it, HDMI is the option to check for those formats.
How are optical and coaxial digital audio different?
| Feature | Optical TOSLINK | Digital coaxial |
|---|---|---|
| How it carries audio | Light pulses travel through an optical-fiber cable. Sony Support describes the connection as using a fiber-optic cable. | An electrical digital signal travels through an RCA-style connection and cable. Sony distinguishes a digital coaxial cable, designed for the digital bitstream, from a standard RCA cable. |
| Port and cable clues | Look for labels such as Optical, TOSLINK, or Digital Audio. The port is commonly square-shaped. | Look for Digital Coaxial or S/PDIF. The jack is RCA-style and may be orange or black; do not confuse it with the red-and-white analog stereo jacks. |
| Format capability | Uses S/PDIF; supported audio depends on the source and receiving device. | Also uses S/PDIF; the electrical cable does not remove the format limits. |
| Typical practical choice | Use it when both devices have matching optical ports and the cable can be routed without sharp bends. | Use it when both devices have matching digital coaxial ports and the installation suits that cable. |
Philips describes both as S/PDIF connections and says they are “equally good and identical since they are digital.” Treat that as practical guidance, not a guarantee that every device implementation, cable run, or setting will behave identically. Cambridge Audio likewise says differences are rarely apparent in ordinary domestic setups with reasonable cables.
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Which connection should you use?
Check the source device’s audio output and the receiver, soundbar, or other destination’s input. When both ends offer the same connection, use the matching cable; for common home use, port availability and device support are usually more useful deciding factors than claims that one cable inherently sounds better.
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Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minute- Optical output to optical input: use a TOSLINK cable.
- Digital coaxial output to digital coaxial input: use a digital coaxial S/PDIF cable. Confirm that both jacks are digital, not analog stereo.
- Different digital port types: use a converter that changes the connection in the required direction.
For cable length, avoid treating a single figure as a universal limit. Cambridge Audio’s comparison, revised in 2025, says that in theory coaxial is superior up to 5 m and optical has the advantage over 5 m. That is a theoretical comparison from the manufacturer, not a guaranteed maximum or a universal result; the devices, cable, and installation matter.
#1 Best Overall
- Bi-Directional Coaxial and Optical Converter: Plug and play, Coaxial to Coaxial&Toslink, or Toslink to Coaxial&Toslink, just a switch button for your input selection
- Supports LPCM2.0/ DTS/ Dolby AC3/ 5.1CH : Multiple digital audio formats to achieve lossless digital audio conversion makes our Converter to be an ideal tool for your shocking home theater
- Supports up to 192 KHz: Noise-free transmission and the highest support 192 KHz 24bit sampling rate for excellent audio output, as well as 32KHz, 44.1KHz, 48KHz, 96KHz, 192KHz
- Noise Reduction and Power indicator: made of high-quality alloy shell material,the converter is fantastic for Noise-reduction and thermal resistance; Power indicator for your Converter working check
- Wide Applicability: 1m Coaxial cable&2m Optical cable provided for Long-distance transmission is perfectly compatible with Apple TV PS4, Xbox 360, Satellite receiver, BR player, Blu-ray Player, UHD TV, DVD, Sound Bar, Amplifier and other devices with Optical and coaxial interfaces
What audio formats can they carry?
Optical and coaxial both carry S/PDIF, so choosing coaxial does not give you a higher-bandwidth audio format than optical. A Philips manual for the BDP5406/F7, BDP3406/F7, and HTS5580W/F7 states that Dolby Digital Plus, Dolby TrueHD, DTS-HD High Resolution, and DTS-HD Master Audio cannot be sent through either optical or coaxial digital audio output because of bandwidth limitations. Check your own devices’ manuals for model-specific support.
For formats such as Dolby TrueHD or DTS-HD Master Audio, investigate HDMI if both the source and destination support it. Klipsch identifies HDMI as a connection that can carry these formats; the supported result still depends on the devices and how they are connected.
Rank #2
- Converts RCA Analog Stereo Audio Signal to Digital Coaxial Audio And Toslink Spdif Optical Digital Audio Simultaneously
- Supports Uncompressed 2-Channel LPCM Digital Audio Signal Output.
- Supports Output Sampling Rate At 48 KHz. Reminder: The Signal Source Of The Analog Port Does Not Support Dolby!
- Provides Electromagnetic-Noise-Free Transmission.Note! Only Outputs 2 Channels of Sound
- Easy to Install and Simple to Operate With 1 Year Warranty From Musou
Why can two digital connections produce different results?
“Digital” describes how audio is carried, but it does not mean every source sends the same signal or that every receiver decodes the same formats. Philips explains that bitstream output sends compressed audio to the external device for decoding, while PCM/LPCM means the source decodes audio and sends uncompressed PCM. Device capabilities and output settings affect what reaches the receiver.
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If there is no sound, an unexpected format, or a different result than you expect, check the source’s audio-output setting and the receiving device’s supported formats. Look for whether the source is set to bitstream, PCM/LPCM, or an automatic mode, and consult both devices’ manuals.
Rank #3
- 【analog to digital audio converter】Converts RCA or 3.5mm AUX analog stereo audio signal to Digital Coaxial audio and Toslink Spdif Optical digital audio simultaneously. Note: It’s not a Digital to Analog audio converter(This product requires unplugging the power source before connecting the audio cable; otherwise, a humming noise will occur)
- 【TV aux to optical for sound bar】Supports uncompressed 2-channel PCM digital audio signal output,Supports output sampling rate at 32K,44.1K,48K audio sampling rate（Note: This device does not feature volume control. To adjust the volume, please use the signal source/amplifier.）
- 【Automatic encoding design 】No software installation, automatic recognition of audio formats, high bandwidth design, no need to have concerns about distortion and loss of some audio content
- 【Small compact design】 Soft light LED indicator to avoid harsh bright light.Designed with aluminum metal housing to guarantee heat dissipation and electromagnetic compatibility，extending product life
- 【Wide Compatibility】Compatible with devices with RCA plug or 3.5mm jack output, such as TV / PS3 / MP3 / DVD player / smartphone / tablet / recorder / laptop / radio / digital audio receiver / home theater system et（Does not work with Bluetooth speakers）
How do you solve an optical or coaxial port mismatch?
A converter bridges connector types; it does not make S/PDIF carry formats beyond its limits. Philips recommends matching the converter’s direction to the signal path:
- TV optical output to receiver coaxial input: use an optical-to-coaxial converter.
- Source coaxial output to receiver optical input: use a coaxial-to-optical converter.
- Digital output to analog-only input: use a digital-to-analog audio converter. This is a different product category from an optical/coaxial converter.
Confirm the converter’s input and output direction and power requirements in its own documentation. Also check that the source and destination support the audio format you intend to send.
Quick Recap
Best Value
- Coaxial to Optical Converter:Converts Coaxial Digital Signal to Optical SPDIF Toslink Audio Signal. Built-in 1m Toslink Cable and a Built-in 1m Coaxial Cable for Long-distance Transmission, Plug and Play
- 192kHz Sampling Rate:Noise-free Transmission, Sampling Rate at 32, 44.1, 48, 96 and 192 kHz,24-bit , Provides Clear Audio
- Audio Format:The Converter Supports LPCM2.0/DTS/Dolby AC3/5.1CH Audio, Providing Lossless Digital Audio Conversion
- Long-distance Transmission:Features a Built-in 1m/3.3ft Toslink Cable and a Built-in 1m/3.3ft Coaxial Cable, it is more Convenient to Connect and Install without Occupying any Space
- Plug and Play:Perfectly Works with Older TV, DVD, Soundbar, Amplifier and Other Devices with Optical and Coaxial Interface. A 5V 1A Adapter (Not Included) Is Recommended to Power It
Rank #4
- Bi-Directional Digital Audio Converter: Support 2-way audio convert: Coaxial to Toslink or Toslink to Coaxial. An input signal switch button that can easily select either SPDIF (Optical/ Toslink) or Coaxial input
- Audio Format: Supports Stereo sound format: Dolby / DTS / ACC / PCM. PCM sampling frequencies can reach to 192KHz, and PCM word length is 16-bit. High definition audio output for your amplifier and speaker, noise-free transmission
- Plug and Play: No need to install any driver. With built-in amplification chip, the converter can also serve as a repeater of audio signal and extend the transferring distance. Comes with a 5V micro USB power cable, which supply stable power for the converter
- Wide Applicability: Compatible with Blu-ray Player, Satellite receiver, BR player, Xbox 360, HDTV, DVD, Amplifier, Sound Bar, Speaker and other device with Optical and coaxial interfaces
- What You Get: 1*Digital Audio Converter, 1*USB Power Cable (adapter is not included), 1*User Manual; Please contact us if you have any questions, we will solve it for you
Connection checks before troubleshooting
- For optical, remove any protective caps and keep the connector clean; avoid sharply bending the cable.
- For coaxial, verify that each port is marked for digital audio, Digital Coaxial, or S/PDIF—not merely an analog RCA connection.
- If the connection is correct but audio still fails, check the source output mode and the receiver’s supported input formats.
- If you need lossless high-resolution surround, check the devices’ HDMI support and manuals rather than trying another S/PDIF cable.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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