Astra Modulation Machine

$499 MSRP

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Astra Modulation Machine
Astra Modulation Machine
Astra Modulation Machine

Astra Modulation Machine

4.3 (15)

Explore the pinnacle of classic chorus, flanging/doubling, and tube tremolo effects.

  • 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

Get the UAD Guitar Amp Bundle for FREE with select purchase! Ends 4/30.

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Details

  • 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

Explore Classic Chorus, Flanging/Doubling, and Tube Tremolo Effects

Built upon our powerful UAFX dual-engine processing and unmatched levels of quirky analog realism, Astra takes you deep down the rabbit hole of classic analog modulation, giving you the most sonically authentic bucket-brigade chorus/vibrato, studio flanger/doubler, and tube-driven tremolo effects ever placed into a single stompbox.

Create with 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.

Get Legendary Flanger/Doubler Effects

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.

Summon 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.

Get a Compact Stompbox Built for the Ages 

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.

Compare Models

Modulation (6 types)

Stereo 1/4"

$499

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$499

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3 Amps / 6 Cabs

Stereo 1/4"

$499

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What They Say

New sounds inspire new songs. UAFX pedals give you new sonic landscapes to play in.

Tyler Bryant

Tyler Bryant & the Shakedown

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

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

UA Studio Sessions

Reviews

4.3
Rated 4.3 out of 5 stars
Based on 15 reviews
Total 5 star reviews: 8 Total 4 star reviews: 4 Total 3 star reviews: 3 Total 2 star reviews: 0 Total 1 star reviews: 0
80%would recommend this product
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15 reviews
  • DC
    D. C.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    5 months ago
    Saw the ratings, had to leave review

    I've always been incredibly fickle with modulation. I generally love flanger, but find its use limited. I think I hate phaser, but always end up using it on my board. Tremolo is... a thing, I guess (hadn't found one I love, but don't feel like I'm missing out). However, when it comes to chorus, I've tried five other pedals and all of them have been somewhere from hate to meh. I've never found a chorus I love. Until this one.

    The day I got it, I unboxed it, hooked it up to my Radial stereo re-amper, and tracked it into a song. It was perfect. It was FINALLY what I expected from a chorus. Maybe I'd tried the wrong five, but this sounded perfect pretty much without even tweaking the knobs.

    For the chorus reason alone, I've fallen in love with this pedal. However, I have to stress that the flanger and tremolo are also the best of each that I now own (three flangers and one other trem). This pedal really is fantastic, and give me "the sound" that I'm looking for.

    Was it expensive? Yes.

    Was it more expensive than the five other choruses I own? Not even close.

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  • DS
    D. S.
    I recommend this product
    Rated 5 out of 5 stars
    1 year ago
    Incredible Sounding Pedal

    The Astra is jam packed with features and sounds that inspire me every day I plug into it.

    I would love to have a full on Uni-Vibe option, that would take this pedal over the top.

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  • GS
    G. S.
    I recommend this product
    Rated 5 out of 5 stars
    2 years ago
    fantastic vintage sound!

    fantastic vintage sound!

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  • DS
    D. S.
    I recommend this product
    Rated 5 out of 5 stars
    2 years ago
    Incredible Sound

    Very lush and rich sounding pedal. It literally sounds expensive and that's exactly what you pay for. UA knocked this one out of the park.

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  • CC
    C. C.
    Rated 3 out of 5 stars
    2 years ago
    Awesome sounds, needs more functionality.

    The stereo chorus is worth the price of the pedal, absolute magic. I wish there was a mode with depth and rate controls though. L The flanger is a PITA to use, I really really wish it was an Electric Mistress instead of the MXR. The trem and phase 90 are great as well.

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Frequently Asked Questions

UAFX pedals require an isolated 9 volt DC, center negative, 2.1 x 5.5 mm barrel connector (same as standard Boss connectors) power supply that can provide the following current requirements: Full-sized UAFX pedals (with two footswitches) require 400 mA (milliamps) of current; Compact UAFX pedals (with a single footswitch) require 250 mA (milliamps) of current

Connect the pedal using a USB-C cable to your compatible computer, and run the UA Connect application to update your firmware.

You can register your pedal with the UA Connect desktop app or the UAFX Control mobile app.

Dual footswitch UAFX pedals have Bluetooth, and you can download the UAFX Control mobile app from the Apple App Store or Google Play Store, to connect to your pedals and access additional functionality.

Each UAFX pedal has unique functionality. We recommend carefully reading the accompanying manual for each pedal here.

Check our Knowledge Base for additional questions

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Note Astra Modulation Machine requires a modern 400 mA isolated power supply (sold separately).