Universal Audio - Astra Modulation Machine
- 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
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With the Universal Audio ASTRA MODULATION MACHINE, 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.
UA ASTRA |
|
| Power requirements | Isolated 9VDC, center-negative, 400mA minimum |
| (power supply sold separately) | |
| Inputs | 2 x ¼” unbalanced TS |
| (input 2 for stereo connections) | |
| Outputs | 2 x ¼” unbalanced TS |
| (output 2 for stereo connections) | |
| Bypass modes | True bypass via mechanical relays or buffered bypass |
| (switchable within UAFX Control mobile app) | |
| 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, ±3 dB |
| USB Type-C | For registration and firmware updates via computer |
| Wireless technology | Bluetooth v5 |
| Dimensions | Height: 2.56 inches, 6.5 cm |
| (with knobs and protrusions) | Width: 3.62 inches, 9.2 cm |
| Depth: 5.55 inches, 14.1 cm | |
| Weight (unboxed) | 1.24 lbs |
| 0.567 kg |
Universal Audio
AUTHORIZED DEALERAvailable in store & online — Nantel Musique
Universal Audio is one of the most recognized names in musical instruments worldwide. Known for exceptional build quality, innovative design, and reliable performance across every price range, Universal Audio instruments are trusted by beginners and touring professionals alike.
at nantel musique, we carry a curated selection of universal audio effects & pedals — each one inspected, set up, and backed by our expert team. every purchase includes our satisfaction guarantee and dedicated after-sales support.

