The Behringer V-TONE BASS DRIVER DI BDI21 is a bass pedal that Behringer describes as a "Bass Amp Modeler/Direct Recording Preamp/DI Box". It combines the features of an active DI (direct injection) box with the company's proprietary tube emulation circuitry, giving what Behringer calls "vintage tube tones for funked-up slap, gonzo overdrive and everything in-between"1. RockBoard's PedalPedia categorises it as "PREAMP OVERDRIVE DI"2, and it sits among the wider field of bass pedals and preamp pedals.
What it does
The BDI21 has two working modes. With the effect engaged, it acts as a recording output DI with tube emulation, shaping your bass tone before it reaches the desk. Behringer also points out that if you just want your instrument's straight, pure tone, stepping on the switch puts the pedal in bypass mode, where it "functions as a superb active DI box"1. That makes it usable as a plain DI box as well as a tone-shaping preamp and overdrive, which is why it often gets filed alongside overdrive pedals as well as DI boxes.
The output side is built for both worlds: Behringer says the output is presented on 1/4" TS or balanced, gold-plated XLR connectors, so the same pedal can feed an amp and a mixer or interface1.
The controls: Drive, Blend, EQ and Level
The pedal carries five dedicated dials plus a Blend control1:
| Control | What it does |
|---|---|
| Drive | Dedicated drive dial1 |
| Treble | Dedicated treble dial1 |
| Bass | Dedicated bass dial1 |
| Presence | Dedicated presence dial1 |
| Level | Dedicated level dial1 |
| Blend | Mixes the amount of tube emulation with the direct bass signal1 |
The Blend control is the one that defines the pedal's character. Behringer explains: "The Blend control allows you to mix the amount of tube emulation you want with your direct bass signal"1. In practice that means you can keep your clean bass tone underneath and add as much or as little of the saturated, tube-emulated signal on top as the part calls for.
Power and connections
The BDI21 runs on a 9V battery or on Behringer's PSU-SB DC power supply, which is not included with the pedal1. RockBoard's PedalPedia lists the power requirement as 9V DC, center negative2.
The PSU-SB power supply does not come in the box, so you need a 9V battery or a separate PSU-SB to power the pedal from the mains1.
Videos
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Questions
Does the Behringer BDI21 run on a battery?
Yes. Behringer says the BDI21 can be powered with a 9V battery or with the company's PSU-SB DC power supply, which is not included with the pedal. RockBoard's PedalPedia lists the power requirement as 9V DC, center negative, so if you use a supply rather than a battery, make sure it matches that polarity and voltage.
Does the BDI21 come with a power supply?
No. Behringer's product page states that the PSU-SB DC power supply is not included. The pedal can run on a 9V battery instead, or you can buy the PSU-SB separately.
Can the BDI21 be used as a plain DI box?
Yes. Behringer says you can use the BDI21 as a recording output DI with tube emulation, or as a standard active DI box when running in bypass mode. Stepping on the switch gives you your instrument's straight, pure tone while the DI output keeps working.
Does the BDI21 have an XLR output?
Yes. Behringer says the output is presented on 1/4-inch TS or balanced, gold-plated XLR connectors, so you can run a balanced XLR line to a mixer or audio interface as well as a standard instrument cable to an amp.
What does the Blend knob do on the BDI21?
The Blend control lets you mix the amount of tube emulation you want with your direct bass signal. In practice you can dial in anything from a fully clean tone to a heavily saturated one, or a mix of the two.
Sources (2)
- BDI21 | Behringer, Behringer
- BDI21 V-Tone Bass Driver by Behringer, RockBoard (rockboard.de PedalPedia), 2026
