The EBS MicroBass 3 is a fully analog, two-channel preamp and DI box for bass, made by EBS and inspired by the company's Fafner II amp1. One channel is clean, with EQ and filters plus a built-in compressor; the other is a drive channel with selectable drive engines and a blend control. Around those two channels sit a dual balanced XLR output section, an effects loop, an aux input and a headphone output, which makes it usable as a practice rig as well as a front end for an amp or a recording setup1.
The clean channel and its filters
The clean channel carries the MicroBass 3's EQ and filtering work. Its filter section includes a bass filter, a shelving type at 12 dB/octave with a gain range of plus or minus 18 dB at 60 Hz1. The clean channel also has Character and Bright filters: the Character filter is a shelving high/low pass type with gain of +6 dB at 80 Hz on the low band, -2 dB at 900 Hz in the midrange, and +3 dB at 7.5 kHz on the high band, while the Bright filter is a shelving type with +10 dB of gain at 10 kHz1.
Two additional filters shape the clean tone:
- Bright filter: a shelving filter with +10 dB of gain at 10 kHz1
- Character filter: a shelving high/low pass design, with Lo +6 dB at 80 Hz, Mid -2 dB at 900 Hz and Hi +3 dB at 7.5 kHz1
The clean channel also includes a Comp/Limit section, with 0 dB of compression gain, a maximum attenuation of 24 dB, a maximum compression ratio of 3:1, a typical attack (80%) of under 10 ms and a typical release (80%) of 100 ms1. Its frequency response is quoted as +0 / -3 dB from 20 to 20,000 Hz1.
The clean channel's input impedance depends on how the channel is configured: 1.5 Mohms with 44 pF in parallel mode, or 10 Mohms with 22 pF in serial mode1.
The drive channel: Lo and Hi engines, Thin, Normal and Deep
The drive channel is where the MicroBass 3 departs from a straight clean preamp. EBS's own dive-deeper article explains the design31:
"The drive channe l incorporates three different drive engines to choose between: Thin, Normal, and Deep."3
Those Thin/Normal/Deep settings are a pre-drive EQ, and the channel also offers HI or LO gain drive engines1. The two engines are built differently: the Lo engine produces soft 2nd harmonics, while the Hi engine is a symmetrical two-stage design with +18 dB of gain1. In practical terms, the Lo engine leans toward the softer, even-order character that bass players often use to add warmth without losing definition, while the Hi engine pushes harder.
The drive channel's controls and specs as the maker lists them1:
| Control or spec | What it does |
|---|---|
| Drive | Gain range of 40 dB |
| Blend | Mixes the drive signal with the clean signal |
| Pre Drive EQ | Thin, Normal or Deep |
| Drive engines | HI or LO gain; Lo is soft 2nd harmonics, Hi is symmetrical 2-stage with +18 dB gain |
| Tone filter | 6 dB/octave low pass, frequency range 700 to 20k Hz |
The drive channel's input impedance is 1.8 Mohms with 22 pF1.
Power and connections
The MicroBass 3 runs on 9V DC and requires 450 mA, with a power supply included1. Its actual draw is 450 mA at idle and up to 750 mA at 9V with headphones at maximum output level, which is why EBS recommends a supply with at least 700 mA available1.
Current demand can rise considerably when the headphone output is used. EBS recommends a 9V DC supply with at least 700 mA available; a correct EBS 9V DC supply is included1.
Internally, the unit converts 9V DC power to an operating voltage of plus and minus 15 V, which EBS says provides headroom like that of high-end equipment1.
The connection set covers live, recording and practice use1:
- Main input: 10 Mohms input impedance1
- Main output: output impedance under 1 kohm, nominal signal level 0 dBv1
- Dual balanced XLR out: nominal output level -20 dBv, XLR pins 1-GND, 2-Hot, 3-Cold; selectable pre or post EQ, or left and right channels in stereo mode1
- Effects loop: mono or stereo; nominal signal level -10 dBv, unity gain, output impedance under 100 ohms, input impedance over 200 kohms with 22 pF1
- Aux input: 20 kohms input impedance, nominal level -10 dBv1
- Phones out: recommended headphone impedance 32 to 200 ohms1
The two XLR outputs are the flexible part of the output section. They can provide pre- and post-EQ signals at the same time, or act as left and right outputs when the effects loop is used in stereo mode1.
Demos and press
EBS published demo videos featuring Erik Arkö, one a demo built around his original music and another in which he turns all the knobs to show what the controls do, with the second recorded straight into the DAW without further processing4.
Videos
EBSSweden
BassTheWorld.com
Bass Bonedo
Questions
How much power does the EBS MicroBass 3 need?
It runs on 9V DC and draws 450 mA at idle, rising to a maximum of 750 mA with headphones at maximum output level. EBS recommends a 9V DC supply with at least 700 mA available, and a correct EBS 9V DC supply is included with the unit.
Can I blend the clean and drive channels on the MicroBass 3?
Yes. The drive channel has its own Blend control, so the driven signal can be mixed with the clean signal. The drive channel also offers HI or LO gain drive engines and Thin, Normal or Deep pre-drive EQ settings.
Does the MicroBass 3 have a headphone output?
Yes, it has a Phones Out with a recommended headphone impedance of 32 to 200 ohms. Note that current demand can rise considerably when headphones are used, which is why EBS recommends a supply with at least 700 mA available.
Is the EBS MicroBass 3 analog?
Yes. EBS describes it as a fully analog, two-channel preamp/DI box, and Premier Guitar's buying guide also lists it as an analog, two-channel bass preamp. Internally it converts 9V DC power to an operating voltage of plus and minus 15 V.
Can the MicroBass 3 output in stereo?
Yes. Its two balanced XLR outputs can carry pre- and post-EQ signals, or act as left and right outputs when the effects loop is used in stereo mode. The effects loop itself can be run in mono or stereo.
Sources (4)
- Microbass 3, EBS Professional Bass Equipment
- Tools for the Task: 6 Peamp Pedals for Bass, Premier Guitar, 2024-08-22
- DIVE DEEPER: THE EBS MICROBASS 3, EBS Professional Bass Equipment, 2026-08-06
- Videos on the EBS MicroBass 3, EBS Professional Bass Equipment, 2019-03-12
