Behringer BDI21 Bass Amp Modeler and DI Box

In the studio or on a cramped stage, the Behringer BDI21 gives bass players the sound of a driven tube amp without hauling heavy gear. Plug in your bass, dial in a touch of drive, and send a balanced XLR straight to the mixing desk—no microphone needed. It is a compact, all-analog pedal that combines amp modeling, overdrive, and a DI box in one rugged metal chassis.

Key specifications

• Analog circuitry with authentic tube emulation for warm, natural overdrive and distortion
• Dedicated bass amp modeling with controls for Level, Blend, Drive, Treble, Bass, Presence, and Shift
• Balanced XLR DI output with ground lift switch for noise-free connection to mixers or audio interfaces
• 1/4" TS input and unbalanced output, plus phantom power capable XLR out
• Buffered bypass preserves signal integrity when the effect is off
• Powered by 9V battery or optional 9V DC adapter (Behringer PSU-SB recommended); current draw approx. 20 mA
• Input impedance 470 kΩ; output impedance 1 kΩ (1/4") and 200 Ω (XLR)
• Frequency response (XLR out): 10 Hz to 40 kHz, +0/-3 dB
• Metal chassis with on/off LED indicator

Why choose it

The BDI21 delivers the punch and grind of a classic tube bass amp in a pedalboard-friendly format. Its Blend control lets you mix the direct signal with the processed tone, preserving low-end clarity while adding harmonic richness. The XLR DI output makes it a practical tool for live sound engineers and home recordists alike, eliminating the need for a separate direct box.

Ideal use cases

• Live performance: run a balanced line to the PA while keeping your amp on stage for monitoring
• Studio recording: capture a polished bass tone directly into your interface without miking a cabinet
• Practice and rehearsal: get inspiring amp-like response through headphones or a small mixer
• Fly rigs and backup: a lightweight alternative to a full amp for touring musicians

Good to know

The Shift control adjusts the mid-frequency center, allowing you to scoop or boost mids for different musical styles. The pedal can be powered by a standard 9V battery, but using a regulated power supply is recommended for consistent performance. Its buffered bypass ensures your dry signal remains strong even with long cable runs.