The Zoom B1X Four is a digital multi-effects pedal for bass. Zoom describes the B1 FOUR and B1X FOUR as taking "your low-end to new heights with over 70 effects and amp models, looper and a built-in" rhythm section, and the pair can run on four AA batteries as well as mains power1. The B1X FOUR is the version with a built-in expression pedal; the Zoom B1 Four is the same unit without one.
What it does
As a multi-effects unit, the B1X Four covers the effects a bass player would otherwise buy as separate pedals: Zoom's product page lists effects chaining, an onboard chromatic tuner, rhythm patterns and looping alongside its dozens of DSP effects and amp models3. That means drive, modulation, delay, pitch and tuning duties can all sit in one box on the board, and the looper and rhythm patterns make it usable for practicing at home without other gear.
The built-in expression pedal is what separates the B1X FOUR from the B1 Four. Zoom says it "can adjust effects, such as volume, wah, delay and pitch," so it can work as a volume pedal, a wah or a live controller for delay and pitch effects without an external expression pedal4.
STOMP mode changes how the unit works in a live setting: rather than switching between whole patches, "STOMP mode lets you turn individual effects on and off," so the footswitches behave more like separate pedals in a chain1.
The B1X Four is a digital circuit, and RockBoard's PedalPedia lists its current draw as 500mA at 9V DC2. That is more than many small pedalboard power supplies deliver per output, so it is worth checking what a supply can provide before daisy chaining it with other pedals.
Power and specifications
| Specification | Value |
|---|---|
| Circuit type | Digital2 |
| Power | 9V DC, center negative2 |
| Current draw | 500mA2 |
| Battery operation | Four AA batteries1 |
Zoom's English manual for the B1 FOUR and B1X FOUR is available as a PDF at zoomcorp.com2.
Related Zoom bass multi-effects
Zoom's bass multi-effects line includes several related units. The Zoom B1 Four is the same platform without the expression pedal4. The Zoom B1on is a guitar-oriented unit in the same family that offers dozens of DSP effects and amp models, effects chaining, an onboard chromatic tuner, rhythm patterns and looping3. Further back in the company's catalog sits the Zoom 3000B, and Zoom's current multi-effects range is covered on the multi-effects pedals and bass pedals pages.
Keeping effects up to date
The B1X Four is a digital unit, with Zoom's own documentation listing its circuit type as digital2. Its power requirements are modest but worth noting for pedalboard planning: it runs on 9V DC, center negative, and draws 500mA, a current draw high enough that a battery or a shared daisy-chain output may not be suitable2.
Videos
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Questions
What is the Zoom B1X Four?
It is a digital multi-effects pedal for bass made by Zoom. Zoom says it offers over 70 effects and amp models, effects chaining, an onboard chromatic tuner, rhythm patterns and looping. The B1X FOUR version adds a built-in expression pedal that can adjust effects such as volume, wah, delay and pitch.
How is the Zoom B1X Four powered?
Zoom says the B1 FOUR and B1X FOUR can operate with four AA batteries. RockBoard's PedalPedia lists the power requirement as 9V DC, center negative, with a current draw of 500mA, so a standard pedal power supply that can supply that current is needed when running from mains power.
What is the difference between the B1X Four and the B1 Four?
Both are bass multi-effects pedals from Zoom with over 70 effects and amp models. The B1X FOUR adds a built-in expression pedal that can adjust effects such as volume, wah, delay and pitch, which the B1 Four does not have.
Sources (4)
- B1 Four / B1xFour, ZOOM
- B1X Four by ZOOM, RockBoard PedalPedia, 2026
- | ZOOM, Zoom Corporation
- B1 Four / B1xFour, ZOOM
