Astra Modulation Machine
The Pinnacle of Classic Chorus, Flanging/Doubling, and Tube Tremolo Effects.
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.
Now You Can:
Texture your tones with iconic Japanese bucket-brigade chorus/vibrato, circa 1976
Explore the outer limits with legendary rackmount bucket‑brigade studio flanging/doubling
Get all the heavenly goodness of 1960's tube-driven tremolo, direct from your favorite American guitar amps
Quickly access sounds with Live/Preset modes, and play with silent switching, preamp coloration, and true/buffered bypass*
Download additional Phaser X90 and Dharma Trem 61 effects at product registration
Build your pedalboard around timeless UA design and robust craftsmanship, built to last decades
TAKE A LISTEN
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
With modern, high‑powered features like studio‑grade conversion, dual‑processing engines, additional downloadable effects at registration, Live/Preset modes, true/buffered bypass,* and silent switching, Astra Modulation Machine has your colors — now go forth, and paint your masterpiece.
Watch the Reviews
“Astra Modulation Machine went straight to work. It’s better than any chorus that I’ve heard. I have a feeling my next ten records are going to be covered with it.”
– Dave Cobb (Rival Sons, Chris Stapleton, Sturgill Simpson)
“UAFX pedals' build quality and sonic goodness are simply incredible, and their vintage outboard tones are a game changer for modern-day creatives.”
– Justus West (John Legend, Alicia Keys, Ty Dolla $ign)
“UAFX pedals have truly recreated classic analog effects of the past, and made them better.”
– Butch Walker (Green Day, Weezer, Taylor Swift)
“UAFX pedals sound amazing. They're instant inspiration with the right amount of tweakability.”
– Lyle Workman (Beck, Sting)
“New sounds inspire new songs. UAFX pedals give you new sonic landscapes to play in.”
– Tyler Bryant (Tyler Bryant & the Shakedown)
“The rich sound quality of UAFX pedals inspire you to play guitar.”
– Chris Traynor (Bush, Helmet)
“The sound quality of UAFX is on a level I've never experienced before. They’re on all the time.”
– Tim Pierce (Michael Jackson, Bruce Springsteen)*True/trails bypass selection available via UAFX Control software (coming Spring 2021).
Note that Astra Modulation Machine requires a modern 400 mA isolated power supply (sold separately). Go here for power supply recommendations.
May 6, 2021
The Best Modulation
I have owned a lot high end modulation pedals and this one tops them all.Read More
May 5, 2021
Mod to the Max
Being in possession of some vintage classics, purchased Astra mainly to enable to have the mod sounds in one unit. Astra went beyond expectations. Upon first placement on my pedalboard, I...Read More
April 15, 2021
The Good: Sounds here are extremely tasteful, stereo is outrageously lush. This pedal will knock plenty, if not all, of your modulations off your board effortlessly. Every setting is...Read More
March 23, 2021
nuff saidRead More
Flagship, no-compromise stompbox offering the most authentic bucket-brigade and tube-driven tremolo effects ever captured in an effects pedal
End-to-end emulation of iconic Japanese chorus/vibrato pedal
Complete circuit capture of legendary '70s rackmount studio flanger/doubler
Stem-to-stern model of tube-driven optical tremolo from classic '60s American amps
Store and recall your favorite preset, silent switching, and true/buffered bypass*
Free Phaser X90 and Dharma Trem '61 effects, downloadable at registration
Astra Modulation Machine
The Best Modulation
I have owned a lot high end modulation pedals and this one tops them all.
Mod to the Max
Being in possession of some vintage classics, purchased Astra mainly to enable to have the mod sounds in one unit. Astra went beyond expectations. Upon first placement on my pedalboard, I have to say the depth and character of each sound is stellar. The build is superb but the effects are the real star here. The research that went into this must have been phenomenal. UA has captured the mojo of the best and this unit outshines my "standard" and now weary classic pedals. Thank you UA
The Good: Sounds here are extremely tasteful, stereo is outrageously lush. This pedal will knock plenty, if not all, of your modulations off your board effortlessly. Every setting is spectacular, usable and inspirational. A painful kind of love can be felt that went into this.
The Sad: Nothing gets wild or remotely experimental, a missed opportunity to add innovative new parameters with the wealth of extra knobs at hand. Toggle switches can be awkward to access. Price, well what did you expect?