The Darkglass Luminal Booster Ultra is a bass effects pedal that blends a booster with a compressor in one unit. Premier Guitar describes it as combining "the rich tone of Darkglass' Harmonic Booster with the unmatched control of an adjustable" compressor, alongside impulse response loading1. Darkglass itself calls it "the next evolution in clean bass tone"2. It sits in the same territory as a preamp pedal or a boost pedal, but with a compressor engine built in.
The pedal builds on the Harmonic Booster, which Darkglass describes as "a revival of the first Darkglass design" and a clean bass preamp in the company's Enhancer Series3. The Luminal Booster Ultra takes that booster circuit and adds compression, EQ, cab simulation and a headphone practice setup. As of late October 2026, Darkglass's product page lists the pedal as sold out2.
What it does and how it is controlled
The pedal's EQ section gives the player detailed tone shaping across six bands. The controls and their ranges, from the Darkglass manual and product page, are54:
| Control | What it does |
|---|---|
| Bass | Low shelf, ±13dB at 80 Hz4 |
| Mid Frequency | Selects the frequency for the mid gain control5 |
| Mid gain | ±20dB at the frequency selected by Mid Frequency5 |
| Treble | High shelf, ±13dB at 5 kHz4 |
| Boost | ±20dB boost or cut5 |
| Character | Push the knob to select between 7 IRs for the cab simulation25 |
The Character knob doubles as the cab sim selector: pushing it steps through seven IR slots on the XLR output2.
Blue and red modes
The pedal has two modes, blue and red, selected by long-pressing the left footswitch. The mode changes the order of the Compression and Harmonic Booster engines in the signal chain2. In practice this means the player can choose whether the compressor acts on the signal before or after the boost and EQ stage, which changes how the compressor responds to level changes from the booster.
The manual also notes that the factory compression mode names referencing the 1176 and SSL are descriptive only, and are not endorsements or affiliations with those brands5.
Connections and silent practice
On the rear panel the pedal carries a 1/4" mono input jack for an instrument or pedalboard output, a 1/4" output jack for an amplifier or another pedal, and a balanced XLR Direct Output for a microphone preamp or PA system2. A ground lift switch disconnects the signal ground on the Direct Output to break ground loops, and does not affect the 1/4" output2.
For practice, the pedal has an internal stereo headphone amplifier that drives a minimum load of 16 ohms from a 3.5mm stereo jack2. A 3.5mm stereo aux input lets you play along with backing tracks from a phone or laptop; it works only with the headphone output, and its level is set from the audio source2.
When the pedal is on bypass, the master volume does not affect the headphone volume. In that case the total volume is adjustable in Darkglass Suite2.
A USB C port connects the pedal to a PC or Mac to use the desktop version of Darkglass Suite, where you can access the available impulse responses or load custom and third-party impulses1.
Power
The Luminal Booster Ultra runs on a regulated 9V DC adapter with a center-negative plug, drawing 400mA5. Premier Guitar's announcement also lists the 9V DC adapter input1. At 400mA the pedal draws more current than most analog effects, so it needs a power supply or isolated output rated for that draw. The manual gives no battery option.
Price and what reviewers said
The street price is $499 USD, as reported by both Premier Guitar and Bass Magazine16. Darkglass's own product page lists a regular price of £380.00 GBP2. Gearnews covered the pedal at its announcement in September 2024, and George Loveridge commented on the cost:
"Which, to be honest is pretty steep."
Gearnews, George Loveridge, 27 September 20247
Registration and support
The warranty is activated by registering the product with its serial number at mypedal.darkglass.com. Darkglass asks that you contact support@darkglass.com before shipping a product to them5.
Videos
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Questions
Does the Luminal Booster Ultra have a headphone output?
Yes. It has an internal stereo headphone amplifier that drives a minimum load of 16 ohms from a 3.5mm stereo jack, so you can practice silently. There is also a 3.5mm stereo aux input for backing tracks, which works only together with the headphone output, with the level set from the audio source.
Does the Luminal Booster Ultra have an XLR direct out?
Yes. A balanced XLR Direct Output connects the pedal to a microphone preamp or PA system, and it carries the cab simulation. A ground lift switch disconnects the signal ground on the Direct Output to break ground loops without affecting the quarter-inch output.
Can I load my own IRs into the Luminal Booster Ultra?
Yes. A USB C port connects to a PC or Mac running the desktop version of Darkglass Suite, where you can use the available impulse responses or load custom and third-party impulses. Seven IR slots are selectable on the pedal itself by pushing the Character knob.
How much does the Darkglass Luminal Booster Ultra cost?
The street price is $499 USD, as reported by Premier Guitar and Bass Magazine. Darkglass's own product page lists a regular price of £380.00 GBP. Gearnews's George Loveridge called that pricing, in his words, pretty steep.
What power supply does the Luminal Booster Ultra need?
It needs a regulated 9V DC adapter with a center-negative plug, and it draws 400mA. That current draw is high for a single pedal, so it needs a power supply or an isolated output rated for it rather than a typical low-current daisy chain.
Sources (7)
- Darkglass Luminal Booster Ultra, Premier Guitar, 2024-10-03
- Luminal Booster Ultra, Darkglass
- Harmonic Booster, Darkglass
- Luminal Booster Ultra, Darkglass
- Luminal Booster Ultra Manual, Darkglass
- Darkglass Announces the New Luminal Booster Ultra for Bass, Bass Magazine, 2024-10-01
- Darkglass Luminal Booster: Ultra Boost For Clean Bass Tones?, Gearnews (www.gearnews.com), 2024-09-27
