Radial Engineering
Radial Stagebug SB-5 Single Channel Passive Laptop Stereo Direct Box
Best passive solution for connecting mobile devices to professional sound systems.
The Radial StageBug SB-5 is a compact, passive stereo direct box designed for seamless connection of laptops, tablets, and mobile devices to professional PA systems. It uses custom-wound transformers to isolate your source device, effectively eliminating ground loop hum and balancing the signal for reliable cable runs up to 300 feet. Connectivity includes stereo 1/4" TRS outputs or a single mono XLR output. Since it's passive, no external power is needed. Essential controls like ground lift and a pad switch ensure clean audio capture from high-output sources. This bundle also includes two Senor Instrument Cables and a Zorro Sounds Polishing Cloth.
$124.99
Owner Satisfaction
4.7
/ 5
Category Rank
30
/ 67
#30 in Direct Boxes
Price vs Category Average
-53%
Below average
Type
Passive Direct Box
/ Passive Direct Box
Who it's for
- Presenters connecting consumer devices to professional PA systems
- Live sound engineers struggling with persistent ground loop interference
- Touring musicians needing a durable, power-free portable solution
Who should skip it
- Audiophiles requiring pristine high-frequency signal integrity
- Engineers needing true stereo separation for playback
- Studio professionals demanding top-tier transformer fidelity
Performance breakdown
Noise Rejection
Transformer isolation effectively silences ground loop hum in any venue.
Signal Integrity
Maintains clean, balanced audio over long cable runs without signal degradation.
Portability
Compact, passive design fits easily into any laptop bag or gig kit.
Connectivity Versatility
Flexible output options handle both stereo and mono professional sound systems.
Ease of Setup
Plug-and-play functionality requires no external power or complex configuration.
Build Durability
Rugged construction withstands the rigors of frequent touring and live performance.
Key Specs
Type
Passive Direct Box
Channel Count
2
Input Connector Type
3.5mm TRS
Output Connectors
1/4" TRS (L/R), XLR (Mono)
Transformer Isolated
Yes
Ground Lift Switch
Included
Pad Switch
Included
Cable Run Capability
Up to 300 feet
Features
- Passive stereo DI for laptops and mobile devices
- Transformer isolation prevents hum and balances signal
- Built-in 3.5mm plug for direct connection
- Stereo 1/4" TRS or mono XLR output
- No external power required
- Ground lift switch eliminates noise
- Pad switch prevents input distortion
- Includes instrument cables and polishing cloth
What customers say
The Radial Stagebug SB-5 is highly valued by audio professionals for its exceptional noise elimination capabilities, especially when integrating consumer electronics like laptops into live sound. Users consistently praise its ability to eradicate ground loop hum, earning it a reputation as a definitive 'hum killer.' Its passive design, featuring quality isolation transformers, reliably delivers clean, balanced stereo signals without needing external power. Reviewers appreciate the signature rugged construction and compact Stagebug form factor, which ensures durability for constant travel. Customers feel the superior performance and immediate improvement in audio fidelity justify the investment over cheaper alternatives. This specialized tool is strongly recommended for anyone needing reliable, noise free signal integrity on the road.
Know before you buy
No, the SB-5 is a passive device. It draws all the power it needs from the signal itself, so you don't have to worry about batteries or external power supplies.
The SB-5 features built-in transformer isolation, which breaks the electrical connection between your laptop and the PA system. This effectively eliminates ground loop hum, which is the most common cause of that persistent buzzing noise.
Yes, you can use the dual 1/4" TRS outputs to maintain a stereo signal. If you only have one channel available on your mixer, you can also use the mono XLR output, which sums the left and right signals together.
The pad switch lowers the input level of the signal. It is particularly useful if you are playing audio from a device with a high output level that is causing distortion or clipping in your sound system.
Because the SB-5 balances the signal, you can run cables up to 300 feet long without experiencing signal loss or increased noise interference.
Still have a question?
Ask Hayley anything about this product before you decide.