
Radial Engineering
Radial Engineering StageBug SB-5 Passive Laptop DI Box
★★★★★
Compact passive DI box that cleanly converts stereo laptop audio to balanced mono for professional PA systems without any power needed.
$124.99*
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*Price sourced from Amazon.com. Last updated:Jun 04, 2026.Price and availability are subject to change.
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Overview
Key Features
Stereo Direct Box Optimized for Consumer Device Audio
Specifications
Type
Passive Stereo Direct Box
Input
1/8" (3.5 mm) Stereo TRS, 5-foot integrated cable
Outputs
2 x 1/4" TRS (Stereo), 1 x XLR (Mono)
Pad
-15 dB
Isolation
Transformer-based
Power
None required (passive)
Brand
Radial Engineering
Model
StageBug SB-5
Pros & Cons
👍 Pros
- Fully passive operation means no batteries or power source to worry about
- Transformer isolation effectively eliminates ground loop hum and buzz
- Built-in 5-foot 1/8-inch cable connects directly to laptops and mobile devices without adapters
- Compact, rugged enclosure is easy to fit on a podium or stage without taking up space
- Flexible output options with both stereo 1/4-inch TRS and mono XLR
👎 Cons
- Sums stereo to mono on the XLR output, which loses stereo imaging for music playback
- Fixed 5-foot input cable cannot be replaced or extended without an additional adapter
- No ground lift switch, relying solely on transformer isolation for noise rejection
- 15dB pad is the only attenuation option with no variable control
Frequently Asked Questions
Does the StageBug SB-5 require batteries or phantom power?
No. It is a fully passive design using transformer isolation, so it requires no batteries, phantom power, or any external power source to operate.
How does the SB-5 handle ground loop hum from laptops?
The internal isolation transformer breaks the electrical ground connection between the laptop and the PA system, effectively eliminating hum and buzz caused by ground loops.
What type of cable connects the SB-5 to a laptop or phone?
It includes a built-in 5-foot cable with a 1/8-inch (3.5 mm) stereo TRS connector that plugs directly into standard headphone outputs on laptops, tablets, and smartphones.
Can the SB-5 output in stereo to a mixing console?
It offers two 1/4-inch TRS output jacks for stereo use or a single XLR output for summed mono. For true stereo to a mixer, you would use both 1/4-inch outputs.
What does the -15dB pad do?
The pad reduces the input signal level by 15 dB, which is useful when the source device outputs a hot signal that could overdrive the mixer input.