Radial SB-2

Radial StageBug SB-2 — Compact Passive DI for Bass, Keyboard, and Acoustic Guitar

The Radial StageBug SB-2 is a compact passive direct box designed for active basses, keyboards, and acoustic guitars that need a clean, balanced signal to the PA. Built around a custom Eclipse ET-DB3 transformer, this DI box delivers the warm, vintage-flavored tone that has made Radial a touring-engineer favorite. The SB-2 is the right choice for working musicians who need studio-grade signal quality in a unit that disappears inside a gig bag.

What Sets the SB-2 Apart

Most budget DI boxes strip out transformer isolation to save cost, but the SB-2 keeps a custom-wound Eclipse ET-DB3 transformer at the heart of the signal path. The stereo-to-mono merge function automatically sums a stereo TRS source into a single balanced XLR feed, saving mixer channels on busy stages. A 14-gauge steel chassis and outer shell protect the unit against the rigors of daily transport.

Transformer-Based Signal Quality

The passive circuit relies on transformer impedance matching rather than active electronics, so the SB-2 introduces no noise floor of its own and requires no phantom power or battery.

• Transformer: Eclipse ET-DB3, 12:1 ratio — handles extreme signal levels with natural compression
• Frequency Response: 20 Hz – 20 kHz (±0.5 dB) — full-range response for bass and keyboard
• Dynamic Range: 115 dB — captures quiet and loud passages without compression artifacts
• THD: 0.005% @ 1 kHz — exceptionally low distortion across the operating range

Inputs, Outputs, and On-Stage Control

The I/O layout is built for fast setup between sets, with a 1/4" input and thru-put feeding the on-stage amp while the XLR output drives the PA.

• Input Pad: -15 dB — tames hot active bass pickups and digital pianos
• Ground Lift: Pin-1 lift on XLR — eliminates hum and buzz from ground loops
• Input Connector: 1/4" — unbalanced hi-Z instrument input
• Output Connector: XLR (AES standard, pin-2 hot) — balanced lo-Z feed to the PA
• Stereo-to-Mono Merge: automatic — sums stereo TRS source into one mono XLR feed

Tour-Ready Construction

Despite its small footprint, the SB-2 is built to survive daily gigging and fits inside an instrument case alongside a guitar or bass.

• Dimensions (L × W × D): 114 × 47 × 34 mm
• Weight: 250 g — light enough to leave in a gig bag
• Chassis: 14-gauge steel — protects internal components from impact
• Power: Passive, no power required
• Warranty: Radial 3-year, transferable