The Gallien-Krueger Plex is a bass preamp, overdrive and DI pedal in one box, with onboard tuning and a USB connection that doubles as a recording interface. Gallien-Krueger describes it as combining "47 years of amp design experience with state of the art technology," and the heart of the design is the company's active four-band "variable Q" equalizer and contour circuit1. Premier Guitar's 2021 review summed it up as a bass overdrive, DI and preamp pedal with features like onboard tuning, USB connectivity, and EQ voicings taken from four Gallien-Krueger amps2.
What it does for your sound
The Plex sits between your bass and the rest of your rig. Its 1/4" output drives the front of an instrument amp or power amplifier, while the DI output sends the signal to the PA or a recording console, so one pedal can cover both your stage amp and the front-of-house feed1. The four-band active EQ and Contour shape the core tone, and the compressor and overdrive are both footswitchable, which Gallien-Krueger says ensures "your performance blends seamlessly into the band or cuts through a crowd"1.
Controls
Every knob on the Plex does double duty: pushing a knob activates secondary functions, with a blue indicator and a readout showing the current option level1.
| Control | What it does |
|---|---|
| Input trimmer | Sets the level coming from your bass2 |
| Four-band active EQ | Bass, low-mid, high-mid and treble, with secondary modes for bass boosting, midrange contouring, treble attenuation and presence2 |
| Bass/bump knob | Push to engage multiple levels of bass enhancement1 |
| Low-mid/contour knob | Press to scoop mids via a contour notch; Gallien-Krueger points to slap tone as the use case1 |
| Compressor section | Level, attack, threshold and ratio controls, with compression ratios from 2:1 up to 20:12 |
| Second row of dials | Overall volume, EQ voicing selection, and the amount of volume, drive and drive intensity in the footswitchable overdrive mode2 |
| Master/voice knob | Selects EQ voicings taken from four Gallien-Krueger amps, shown on a numerical display; Premier Guitar notes about 30 examples are listed in the manual2 |
The overdrive side offers five modes with varying degrees of intensity2. If you are comparing it against a dedicated overdrive pedal or a standalone compressor pedal, the Plex folds both into the preamp, along with the DI and tuner.
Tuner, DI and connections
The compressor footswitch is dual purpose: a single tap engages the compressor, and double-tapping activates a chromatic tuner display on the LED readout2. Premier Guitar noted that G-K said the next firmware update would change the tuner disengage to a single tap2.
The jack layout covers most stage and studio needs2:
- 1/4" jacks for input, output, send and return
- Balanced XLR DI out with switchable ground lifting and pre/post EQ'ing
- Two 1/8" jacks, for headphones and aux-in
- USB jack for firmware updates and use as a recording interface
The send and return jacks mean you can loop other pedals, such as a tuner pedal or an effect the Plex does not cover, into the front of the preamp2.
Power and firmware
The Plex is powered by an included 9V power supply, according to Premier Guitar's review2. Firmware updates run over the USB jack: during an update, the pedal is recognized as a drive on a PC or Mac, labeled "GK PLEX"3. Gallien-Krueger's firmware notes list improvements to the noise reduction attack and release characteristics3.
Build and what reviewers said
Premier Guitar's reviewer described a matte-black-finished aluminum enclosure with comfortably rounded, chamfered edges and top-mounted hex screws, calling the pedal "compact and robust" with a "ballsy vintage-flavored overdrive" and "feature-packed and useful for many scenarios"2.
"Compact and robust. Ballsy vintage-flavored overdrive. Feature-packed and useful for many scenarios."
Note that the price has moved considerably: Premier Guitar listed the Plex at $319 in August 20212, while Gallien-Krueger's own product page advertises $645.00 as of October 20261.
A different pedal shares the Plex name: the Foxgear Plex 55 is a miniature 55-watt power amp plus preamp in pedal format, not a related Gallien-Krueger product4.
Videos
Sweetwater
Andertons Music Co
Andertons Music Co
Questions
Does the Gallien-Krueger Plex have a built-in tuner?
Yes. The compressor footswitch is dual purpose: a single tap engages the compressor, and double-tapping brings up a chromatic tuner display on the LED readout. Premier Guitar noted in its 2021 review that G-K said a coming firmware update would change the tuner disengage to a single tap.
Does the Plex have an XLR DI output?
Yes. Alongside 1/4-inch jacks for input, output, send and return, the Plex has a balanced XLR DI output with switchable ground lifting and a pre/post EQ option, so it can feed a PA or recording console while you also drive an amp on stage.
Can the Plex be used as a USB audio interface?
Yes. The USB jack handles both firmware updates and recording, so the Plex can serve as a recording interface for a computer. Premier Guitar described it as a bass overdrive, DI and preamp pedal with onboard tuning and USB connectivity.
What power supply does the Plex use?
The Plex runs on a 9V power supply, which is included with the pedal according to Premier Guitar's review. Gallien-Krueger's current product page lists the pedal at $645.00 as of October 2026.
How many overdrive modes does the Plex have?
Five. Premier Guitar's review describes five overdrive modes with varying degrees of intensity, with controls for the amount of volume, drive and drive intensity in the footswitchable overdrive section.
Which Gallien-Krueger amps are the Plex EQ voicings taken from?
The EQ voicings are taken from four Gallien-Krueger amps, selected through the master/voice knob with a numerical display. Premier Guitar notes that around 30 examples are listed in the manual.
Sources (4)
- Plex Preamp, Gallien-Krueger
- Bass OD/DI/Preamp Pedal Roundup, Premier Guitar, 2017-05-08
- Plex Firmware, Gallien-Krueger
- New Pedal: Foxgear Plex 55 Amp, Delicious Audio, 2021-01-29
