Radial Engineering
Radial Engineering USB-Pro
Best professional interface for clean computer-to-PA audio connections.
The Radial USB-Pro is a high-resolution stereo digital audio converter and direct box, designed to seamlessly transfer digital audio from any computer to analog outputs. It offers a stereo pair of balanced XLR outputs for connecting to PA systems or mixing consoles, with plug-and-play simplicity across major operating systems. For critical monitoring, a 3.5mm analog output is provided for headphones. The unit also includes a mono-sum switch and isolation transformer switches to effectively reduce ground loop noise, ensuring clean audio transfer.
$279.99
Owner Satisfaction
4.8
/ 5
Category Rank
1
/ 67
Best Direct Boxes
Price vs Category Average
+6%
Above average
Interface
USB
/ USB
Who it's for
- Professional technicians connecting laptops to large-scale sound systems
- Live sound engineers battling persistent electrical hum and noise
- Touring musicians needing gear that survives heavy road use
Who should skip it
- Casual hobbyists on a strict budget
- Recording artists needing microphone or instrument input capabilities
- Audiophiles requiring ultra-high-resolution 192kHz playback support
Performance breakdown
Noise Floor Suppression
Isolation transformers effectively eliminate ground loop hum in complex stage setups.
Build Durability
Rugged aluminum construction withstands the rigors of professional touring environments.
Setup Simplicity
Plug-and-play functionality ensures instant connectivity without complex driver installations.
Signal Integrity
High-resolution conversion maintains pristine audio fidelity from digital to analog.
Monitoring Versatility
Dedicated headphone output provides essential real-time audio verification for engineers.
Output Flexibility
Balanced XLR outputs integrate seamlessly into any professional mixing console.
Key Specs
Interface
USB
Channels
Stereo (2 channels)
Connectors
Balanced XLR audio outputs, 3.5mm analog output, USB type-B port
Compatibility
Windows XP, Windows 7/8, Mac OSX
Host Interface
USB 3.0
Outputs
Stereo pair of balanced XLR audio outputs
Monitoring
3.5mm analog output
Functionality
Direct box with ground lift and isolation transformer options
Features
- High-resolution stereo DAC and direct box
- Plug and play across major operating systems
- Balanced XLR outputs with level control
- Headphone monitoring via 3.5mm output
- Mono-sum switch for phasing checks
- Ground lift switch for hum reduction
- Isolation transformer for noise reduction
- Automatic sound card recognition
What customers say
Reviewers consistently laud the Radial Engineering USB Pro for its exceptional build quality and unwavering reliability in professional settings. The core praise centers on its ability to flawlessly eliminate ground loop hum using high-quality isolation transformers, ensuring clean audio output. Users appreciate the simple plug and play operation and robust XLR connections that streamline complex setups. While it carries a premium price, customers agree that the superior performance, durability, and guaranteed noise-free integration into high-end sound systems make this device an essential professional investment, solidifying its reputation as the industry standard for USB DI boxes.
Know before you buy
No, the USB-Pro is a true plug-and-play device. It is automatically recognized by Windows and Mac operating systems as an external sound card without the need for additional software or drivers.
No, the unit is entirely USB bus-powered. It draws all the necessary power directly from your computer through the USB connection, keeping your setup clean and portable.
The USB-Pro features built-in isolation transformers and a ground lift switch. Engaging the ground lift switch disconnects the ground path between the computer and the audio system, which is the most effective way to eliminate ground loop hum.
The 3.5mm output is designed for convenient headphone monitoring of the digital signal. While it is excellent for checking your audio, the primary balanced XLR outputs are the intended choice for connecting to professional mixing consoles and PA systems.
The mono-sum switch combines the left and right stereo channels into a single mono signal. This is particularly useful for troubleshooting phase issues or when you need to send the same signal to two different speakers or channels.
Yes, the USB-Pro is compatible with USB 3.0 ports. It uses a standard USB Type-B connection and will function seamlessly with modern computer ports.
Still have a question?
Ask Hayley anything about this product before you decide.
Ready to buy?
$280