Cubilux USB C to SPDIF Transmitter, Unidirectional Type C to Optical Audio Output Adapter with 192KHz/24bit DAC for MacBook Pro/Air, Laptop, Computer
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AI Verdict
This is a simple, budget adapter for sending optical audio from your computer to a soundbar or DAC, but it's not for TVs or complex 7.1 setups.
This is a strong fit if your only goal is to get a clean optical audio signal out of a computer that lacks the port. Its value plummets outside this exact scenario due to its strict computer-only, output-only design. It solves one specific problem well but is completely inflexible for anything else.
If you need more inputs, 7.1 surround, or compatibility with devices other than a computer, search for an 'HDMI audio extractor' or a 'USB external sound card'.
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Pros
- Supports hi-res audio up to 192KHz/24-bit for a clean digital signal.
- Driverless, plug-and-play operation on modern macOS and Windows systems.
- Can pass a 5.1 surround sound signal with the right media player and settings.
- Lightweight at only 0.704 ounces with a durable aluminum housing.
- Users confirm it works instantly on M1/M2 MacBooks without any setup.
Cons
- Does not support 7.1 surround sound due to USB limitations.
- Strictly unidirectional, it only sends audio from USB-C to optical, it cannot receive.
- Incompatible with most TVs, car USB ports, and game consoles like PS5 or Xbox.
- Achieving 5.1 surround requires specific software (like VLC or Kodi) and manual audio configuration, it's not automatic.
Dimension Scores
It delivers a bit-perfect digital signal up to 192KHz/24-bit, so final quality is determined by your external audio gear.
This score is neutral because as a digital transport, it does not control volume or bass; that is handled by the connected amplifier or DAC.
Connectivity is very limited: it's strictly one-way (USB-C to Optical) and only works with computers.
The aluminum alloy case is durable and it weighs less than an ounce, making it extremely portable.
Best For
- Connecting a modern laptop without an optical port to an older AV receiver for 5.1 movies.
- Sending a bit-perfect digital audio stream from a PC or Mac to an external DAC.
- A simple, portable audio output solution for a mini PC connected to a stereo system.
- Recording from a computer to a MiniDisc player via its optical input.
Not Recommended For
- Connecting a TV's USB port to a soundbar; it's not designed for TV compatibility.
- Anyone needing 7.1 surround sound for a high-end home theater.
- Users who want a simple plug-and-play solution for 5.1 surround without changing software settings.
Watch Out For
- 5.1 surround sound is not automatic; you must use a media player like VLC or Kodi and manually set the audio device to passthrough the signal.
- It will not work if plugged into a TV or game console's USB port, as those ports are not full-featured for this type of audio output.
- Some users report intermittent audio or stuttering, which can sometimes be fixed by changing the sample rate in your computer's audio settings to match your receiver.
- The adapter is only a transmitter; it cannot be used in reverse to get audio from an optical source into your computer's USB-C port.
Full Specifications
| ASIN | B09QFYNB7Y |
| Color | black |
| Item Weight | 0.704 ounces |
| Manufacturer | Cubilux |
| Connector Type | USB Type C |
| Item model number | CUB-USBOPT |
| Compatible Devices | USB-C or Thunderbolt 4/3 compatible devices |
| Product Dimensions | 9 x 0.8 x 0.6 inches |
| Item dimensions L x W x H | 9 x 0.8 x 0.6 inches |
| Specific Uses For Product | Computers, Amplifiers |
What Buyers Say
The most common reaction to this dongle is relief that it 'just works' for connecting a laptop to an older sound system. Many users on Mac and Windows report it's instantly recognized, letting them finally get a clean 5.1 signal from their computer to a soundbar or receiver. The biggest source of frustration comes from people buying it for an incompatible device, like a TV or game console, where it absolutely will not work. Getting 5.1 surround sound isn't always straightforward and often requires digging into the audio settings of a specific media player like VLC, which catches some people off guard. The metal housing gets consistent praise for feeling sturdy and well-made for the price.
“i was about to throw out my perfectly good old receiver just because my new laptop has no optical port, this little thing saved me hundreds of dollars.”
Common Praise
- It works plug-and-play on my MacBook Pro, no drivers needed.
- Finally lets me send 5.1 surround from my PC to my old Logitech Z-5500 speakers.
- The sound output is perfectly clean, with no static or electronic interference.
- Confirmed it passes a 192KHz/24-bit signal to my receiver.
- The aluminum casing feels surprisingly premium and durable.
- It's a simple, effective fix for laptops that have dropped the optical audio port.
Common Complaints
- I couldn't get it to work with my Samsung TV's USB port.
- Getting 5.1 surround sound required changing settings in my media player, it wasn't automatic.
- The audio cuts out or stutters sometimes.
- It does not support 7.1 surround sound.
- It's output only, I mistakenly bought it to record from an optical source.
- There's no indicator light to confirm it has power or is working.
Ownership Tips
- After a few weeks, I've noticed that streaming services in a web browser (like Netflix) often won't output 5.1 surround through this, you need to use the Windows app or a dedicated media player.
- It can get a little warm to the touch during a long movie, but never worryingly hot.
- If my computer goes to sleep, sometimes I have to unplug and replug the adapter for the sound to work again.
- The included mini-TOSLINK adapter is tiny and feels like it could be easily lost; I recommend keeping it attached to the cable.
- I had to go into my Windows Sound Control Panel and disable all other audio devices to make this the permanent default for it to work reliably every time.
Frequently Asked Questions
Does this work with a PS5, Xbox, or Nintendo Switch?
No, this adapter is designed specifically for computers and is not compatible with game consoles.
How do I get 5.1 surround sound to work?
You need to play a file that has 5.1 audio using a media player like VLC or Kodi, then go into the audio settings of that player and select the Cubilux adapter as the passthrough output device.
Will this work if I plug it into my TV's USB port?
No, most TV USB ports are not designed to output audio signals this way and are not compatible.
Do I need to install drivers for this on Windows or Mac?
No, it's a plug-and-play device and should be recognized automatically by modern operating systems without any extra drivers.
Can I use this to connect my CD player's optical out to my laptop's USB-C port?
No, this adapter is for output only. It sends a signal from USB-C to an optical port, it cannot receive an optical signal.
Does this adapter support Dolby Atmos?
No, it supports up to 5.1 surround sound but does not support 7.1 or object-based audio formats like Dolby Atmos.
Will this improve my sound quality?
It bypasses your computer's internal sound card to send a pure digital signal. The final sound quality will depend on your external DAC or receiver, but this ensures the source signal is clean.
Buying Guide
You need to understand that this device is just a translator, not a sound card. It takes the digital audio from your computer's USB-C port and turns it into an optical (SPDIF) signal that your soundbar or receiver can understand. It won't improve the sound itself, but it gives you a connection that your computer might be missing. Its entire job is to bridge that one specific gap.
Unidirectional
This means it's a one-way street. Audio only flows OUT of your computer's USB-C port. You cannot use it to get audio from your TV's optical port INTO your computer.
192KHz/24bit
Think of this as the 'resolution' of your audio. This is a high-quality standard that means no audio detail is lost between your computer and your sound system. It's more than enough for movies and music streaming.
5.1 Surround
This means it can pass the six separate channels of audio for a standard surround sound system. It won't create surround sound from a stereo song; your movie or game file must already have a 5.1 audio track for it to work.
Alternatives
If this doesn't fit, and you need to connect a TV or game console, search for an 'HDMI audio extractor'. If you need more features like 7.1 surround, a microphone input, or more connection types, you should look for a 'USB external sound card'.
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