Universal Audio has taken a selection of their finest DSP-powered emulations of classic effects and packed them into thoughtfully designed, ultra-robust guitar pedals that are a tone chaser’s dream come true. The Universal Audio Astra Modulation Machine puts three legendary modulation effects at your feet — a bucket brigade chorus, a flanger/doubler, and a vintage amp tremolo — all of which uncannily bottle realistic analog character and vibe. With true bypass switching and an optional buffered bypass, the Astra Modulation Machine keeps your core tone intact while allowing you to layer on swathes of gorgeous modulation. Guitarists at Music Experience often reach for the UAD software versions of these effects when shaping their guitar tone in the box, so we’re thrilled to be able to now transport these tones to the stage. Plus, the Astra Modulation ups the ante on all these effects, offering stereo and dual-mono operation and a preset mode to store your favorite settings and switch between effects during a performance. With its unmatched sonic authenticity, the Universal Audio Astra Modulation Machine pedal is bound to become your new favorite pedal for infusing your playing with warbles, wobbles, and wash!

Chorus Brigade

Based on the beloved Japanese chorus ensemble effect that hit the streets back in 1976, the Chorus Brigade conjures up the lush, swirling analog chorusing popularized by guitar legends such as Andy Summers, Jeff "Skunk" Baxter, and Brian May, as well as modern players like John Frusciante, Alex Turner, and Kevin Parker, among others. The Chorus Brigade features two modes: a set-it-and-forget-it chorus and a tweakable vibrato with Depth and Speed controls. Additionally, Universal Audio included the original big gray pedal’s preamp level control for driving the effect into some seriously glorious saturation!

Flanger/Doubler

Making its debut in the late 1970s, a bright blue rack-unit flanger and doubler found its way into the rigs of countless guitarists during the 1980s and 1990s. Universal Audio perfectly captured this “meta” effect, which used bucket brigade circuitry to mimic the analog tape flanging effect that was heavily employed by psychedelic bands in the 1960s. Unabashedly lo-fi, the Flanger/Doubler pulls off a range of effects, from unstable-tape-machine wow and flutter to underwater wooshing — all with a deliciously scooped tone and loads of grit.

Trem 65 

When it comes to tremolo, nothing is quite like the optical tube tremolos featured on vintage tube combo amps — the ones boldly mislabeled “vibrato”! The Trem 65 serves up that wide-swing sound in spades, with switchable sine and square wave modes, so you can keep it subtle or go in for the hard chop. And for an even more dramatic effect, switch into stereo mode for wall-to-wall panned tremolo!!

Two additional free effects: X90 Phaser and Dharma Trem 61

As if the three awesome stock effects weren’t enough, Universal Audio sweetens the pot with two free effects when you register your Astra Modulation Machine — the X90 Phaser and Dharma Trem 61 — which can be loaded onto the pedal via USB. The X90 Phaser gives you access to the “script” and “block” versions of the iconic orange phaser pedal; the Dharma Trem 61 emulates the unique vintage harmonic tremolo circuit installed in certain brownface, blonde tube combos, with a modern dynamics processor that lets you ramp up or ramp down the tremolo speed to a defined rate!

UAFX Control app for even more control

Download the UAFX Control app for iOS or Android and expand your sonic options. The app lets you witch between true bypass and buffered bypass on your Astra Modulation Machine. Plus, the app lets you change the behavior or the right footswitch to choose a preset, tap tempo, or both.

What Universal Audio Says...

Taking you deep down the rabbit hole of classic analog modulation, UAFX Astra Modulation Machine serves up the most sonically authentic bucket-brigade chorus/vibrato, studio flanger/doubler, and tube-driven tremolo effects ever placed into a single stompbox. Built upon our powerful new UAFX dual-engine processing and unmatched levels of quirky analog realism, Astra delivers richly addictive vintage modulation, beautifully crafted to inspire you for decades.

• Texture your tones with iconic Japanese bucket-brigade chorus/vibrato, circa 1976
• Quickly access sounds with Live/Preset modes, and play with silent switching, preamp coloration, and true/buffered bypass**
• Explore the outer limits with legendary rackmount bucket‑brigade studio flanging/doubling
• Download additional Phaser X90 and Dharma Trem 61 effects at product registration
• Get all the heavenly goodness of 1960's tube-driven tremolo, direct from your favorite American guitar amps
• Build your pedalboard around timeless UA design and robust craftsmanship, built to last decades

Chorus Brigade: Iconic Japanese Modulation

Upon its release in 1976, this legendary gray bucket-brigade stompbox changed the sound of music with its thick, luxuriant chorus and wavy vibrato. Astra's Brigade Chorus mode gives you the most complete circuit emulation of this landmark unit — including its preamp section for authentically thick, saturated sounds — letting you paint with subtle ripples of analog texture and tone, adding chewiness, shimmer, and motion to everything you play.

Flanger/Doubler: A Rackmount Studio Classic

Packed with late-'70s bucket-brigade tech, this classic rackmount studio flanger/doubler is famous for stunning whoosh effects, organic thickening, and a parade of wild sounds that go way beyond typical flanger boxes. Astra's Flanger/Dblr effect is the only end‑to‑end circuit emulation of this ultra‑rare unit, capturing its original features to a "T" and putting impossibly dense, complex flanging/doubling right at your feet.

Trem 65: Authentic Tube Amp "Shake"

Few things compare to the optical tube-driven tremolo of '60s American amplifiers. Deep, undulating, and the very essence of vibe, Trem 65 is a faithful emulation of this classic circuit. From shimmering ripples to choppy mayhem, every dynamic detail is captured in UA style, down to the complex interactions between the light source photoresistor and 12AT7 driver tube. Plus, you can explore further and create your own trem textures with variable sine and square wave settings.

Dual Stereo Modulation Engines for Endless Creativity

Astra's UAFX engine powers separate stereo instances of each modulation effect, thanks to its unique dual‑engine processing. It's like having two bucket-brigade hardware units running simultaneously — or even dual tremolo circuits — giving you a full stereo spread of complex, jaw‑dropping textures.

A State-of-the-Art Stompbox