The Shift Line A+ CabZone Bass is a digital, IR-based cabinet simulator and DI box for bass, built as a small pedal with recessed knobs so it can sit anywhere on a pedalboard1. It is a special version of the CabZone X with bass-specific firmware installed1, and it does two jobs at once: it replaces a bass rig's speaker cabinet with a set of recorded cabinet impulses, and it feeds a mixing desk or interface through a balanced XLR output. Shift Line describes it as "not only an IR-based cabsim but also a full-fledged DI box"1.
The unit is built around the ADAU1701 digital signal processor1, in a sturdy aluminum enclosure measuring 110 x 72 x 32mm and weighing 200g1. It carries 10 impulses from the Shift Line Bass IR Pack, selected by a single knob, plus a set of virtual power amp emulations1. Shift Line lists it at $1691.
What it does for a bass player
A cabinet simulator takes the place of a speaker cabinet in the signal chain1. You feed the CabZone Bass from your amp's output, a preamp pedal or your bass directly, and it applies the frequency response of a recorded bass cabinet, so what reaches the desk or your headphones sounds like a mic'd rig rather than a raw line signal1. Because the CabZone Bass also emulates the power amp stage that drives a cabinet, it can reproduce the push and roll-off of a tube power section without an amp in the room1.
The multiple outputs make it a live and recording tool at once1. The THRU output is unbuffered, so it can pass the untouched signal on to a real amp, while the XLR balanced output goes to front of house at a fixed maximum level, and the PHONES jack supports silent practice. The AUX input lets you mix in a backing track alongside your bass for headphone playing1.
The controls
The front panel keeps everything on knobs and two small switches1.
| Control | What it does |
|---|---|
| CAB knob | Selects the impulse; 11 positions, OFF plus 10 bass impulses1 |
| AMP knob | Selects the power amp emulation1 |
| VOLUME knob | Controls the OUT and PHONES volume; the XLR output is fixed at max level1 |
| PAD switch | Selects input sensitivity: INST at instrument level (0dB, 500kOhm) or LINE at line level (-6dB, 20kOhm)1 |
| GND switch | Eliminates ground loops on balanced connections; bottom position connects grounds, top position disconnects them1 |
| LED | Green in standard mode, blue when USB is used, yellow on input overload1 |
There is no bypass switch. The bypass is digital, and the CAB and AMP sections disengage separately by turning their knobs to OFF1. That means the pedal is always in the signal path when connected, but you can take the cabinet and power amp modeling out independently, for example to run it as a plain DI.
Bass cabinet impulses and power amp emulations
The CAB knob's 10 impulses come from the Shift Line Bass IR Pack1. The maker's page names six of the cabinets:
| CAB position | Cabinet |
|---|---|
| 01 | EBS PL 4101 |
| 02 | Hartke XL4101 |
| 04 | Ampeg Heritage B151 |
| 05 | Sunn 200s1 |
| 06 | Mesa RR2151 |
| 07 | Ampeg SVT-810E1 |
The AMP knob selects the power amp emulation, and the maker describes five bass models1:
| AMP position | Power amp model |
|---|---|
| A | Neutral Bass: clean and neutral, -1dB roll-off at the edges of the frequency range, practically impossible to overload1 |
| B | Deep Bass: loud and clear, slight boosts at 55Hz and 10kHz, almost impossible to overload with input volume1 |
| C | 6L6 Bass: virtual push-pull Class AB amp based on 6L6 tubes adapted to bass, mild roll-off at 20Hz and 18kHz, slight boost around 100Hz1 |
| D | 6L6 Deep Bass: same 6L6-based virtual push-pull specs as 6L6 Bass, with mild boosts at 40Hz and 15kHz1 |
| E | 6550 Bass: emulation of power amps based on large beam tetrodes with soft clipping, lows slightly boosted around 40Hz1 |
Position A gives a flat, clean path for players who want the cabinet impulse alone, while the tube models add the character of a driven power section before the cabinet filter1.
Power and connections
The CabZone Bass runs on a universal 9 to 12V DC intake with a comparatively low current draw: 200mA at 9V and 150mA at 12V1. The jack is negative tip, 2.1/5.5mm, and Shift Line specifies a regulated PSU only1.
The device cannot be powered by battery1. It can, however, be powered via USB, including by power banks, through a Micro-USB port1, which is unusual for a pedal and makes it practical for desktop recording or travel without a pedalboard power supply.
On the balanced side, phantom power is safe: Shift Line states that the +48V phantom power of the balanced line is insufficient for the preamp to operate on and will not damage the device1. So the XLR can be plugged into a console with phantom power engaged.
Versions: CabZone X and the Bass firmware
The A+ CabZone Bass sits in a small family of Shift Line cabinet simulators. The CabZone LE, now discontinued, was an IR-based cabinet simulator with 10 stock impulses, 8 for guitar and 2 for bass, running on 9 to 18V DC at 80mA2. Its CABINET knob selected the impulse, its VOLUME knob controlled the OUT and PHONES outputs, and its PAD switch chose between 0dB and -6dB input attenuation2. One of its bass impulses, at CABINET knob position 09, was a SUNN 200s bass cabinet with two 15-inch speakers, recorded with three different mics and some EQ, using a neutral power amp for the capture2.
The CabZone X is the newer generation of the digital IR-based cabinet simulator3, with a set of 10 power amp emulations for guitar and bass3. RockBoard's PedalPedia lists the CabZone X at 12V DC, center negative4. The CabZone X Parallax is a further new generation, substantially expanded from the CabZone LE5.
The firmware question matters for bass players choosing between them. The CabZone X Standard firmware contains virtual power amps and cabinet impulses designed mostly for guitar, while the Bass firmware version contains those made for bass, and Shift Line says the update to the Bass version is reversible1. The same split applies to the CabZone X Parallax, whose Standard and Bass firmware versions follow the same pattern, with the Bass update also reversible5. In other words, a CabZone X bought for guitar can be switched over to bass impulses and bass power amp models, and switched back.
The A+ CabZone Bass is the same hardware as the CabZone X, shipped with the bass firmware already installed1. The CabZone LE that preceded the line is discontinued2.
Videos
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Questions
Can the A+ CabZone Bass be powered by USB or a power bank?
Yes. Shift Line says the device can be powered via USB, including by power banks, through its Micro-USB port. The LED turns blue when a USB connection is used, instead of the green of standard operation. It also runs from a conventional 9 to 12V DC supply with a negative tip, 2.1/5.5mm jack.
Does the CabZone Bass take a battery?
No. Shift Line states plainly that the device cannot be powered by battery, and that a regulated PSU only should be used. Power comes from a 9 to 12V DC adapter with a negative tip, 2.1/5.5mm jack, or from USB including power banks.
Will phantom power damage the CabZone Bass?
No. Shift Line says the +48V phantom power of the balanced line is insufficient for the preamp to operate on and will not damage the device. So the XLR output can be plugged into a mixing console with phantom power switched on without harm.
Which bass cabinets are on the CabZone Bass CAB knob?
The CAB knob has 11 positions: OFF plus 10 impulses from the Shift Line Bass IR Pack. Named cabinets include the EBS PL 410, Hartke XL410, Ampeg Heritage B15, Sunn 200s, Mesa RR215 and Ampeg SVT-810E.
Can a CabZone X be updated to the bass firmware?
Yes. The CabZone X ships in a Standard firmware version with virtual power amps and cabinet impulses designed mostly for guitar, and a Bass firmware version holds those made for bass. Shift Line says the update to the Bass version is reversible.
Sources (5)
- A+ CabZone Bass, Shift Line, 2026
- A+ CabZone LE, Shift Line, 2026
- A+ CabZone X, Shift Line (shift-line.com), 2026
- CabZone X by Shift Line, RockBoard PedalPedia, 2026
- A+ CabZone X Parallax, Shift Line, 2026
