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Astra Modulation Machine Pedal

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Astra Modulation Machine Pedal
Astra Modulation Machine Pedal
Astra Modulation Machine Pedal
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Astra Modulation Machine Pedal

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

Limited Availability. While Supplies Last.

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  • 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
  • Get realtime MIDI control of effects parameters*, improved Bluetooth and hardwired connections, and more using updated UAFX Control app
  • 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
Downloads & Details

Downloads

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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
  • Supports MIDI-over-USB*, improved Bluetooth and hardwired connections, and more via the updated UAFX Control app
  • 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.

Expand your Effects with MIDI Control

Using its rear panel USB-to-MIDI connection, Astra Modulation Machine fits right into your programmable MIDI rig, receiving preset changes, BPM clock sync, and more. It’s the fast ticket to live performance heaven*.

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Powerful App Control with Hardwired or Bluetooth Connection

The UAFX Control app is key to deep tone shaping, letting you customize, save, and manage your effects. Plug right in with a direct "hardwired" USB connection to your smart phone, or enjoy rock-solid control over Bluetooth.

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.

Specifications

Specifications

Power requirements (power supply sold separately)
Isolated 9VDC, center-negative, 400mA minimum
Inputs
2 x 1/4" unbalanced TS (input 2 for stereo connections)
Outputs
2 x 1/4" unbalanced TS (output 2 for stereo connections)
Bypass modes (switchable within UAFX Control app)
True bypass via mechanical relays or buffered bypass
Input impedance
500 Kilohms (Mono In) 1 Megohms (Stereo In)
Output impedance
500 Ohms
Maximum input level
12.2 dBu
Maximum output level
12.1 dBu
Frequency response
20 Hz to 20 kHz, ±1 dB
USB Type-C
For registration and firmware updates via computer
Wireless technology
Bluetooth v5 Transmitted Frequency Range: 2.400 GHz – 2.4835 GHz Maximum Output Power: +4.35 dBm
Dimensions (with knobs and protrusions)
Height: 2.56 inches, 6.5 cm Width: 3.62 inches, 9.2 cm Depth: 5.55 inches, 14.1 cm
Weight (unboxed)
1.24 lbs, 0.567 kg

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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

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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