The Universal Audio UAFX Astra Modulation Machine is a stereo digital multi-modulation pedal that puts three emulated modulation effects in one box: a chorus, a flanger/doubler and a tremolo. Universal Audio announced it in January 2021 as one of a trio of UAFX pedals, alongside the Golden Reverberator and Starlight Echo Station, marking the company's entry into the guitar pedal market12.
Three modulation effects in one pedal
The Astra offers three modulation types: Chorus Brigade, Flanger DBLR and Trem 65, each with secondary modes for Vibrato, Doubling and more2. Guitar World describes the set as a bucket brigade chorus based on the legendary CE-1, a bucket brigade flanger/phaser based on MXR's rackmount unit, and a vibrato based on classic vintage 60s Fender amps4. Delicious Audio's buying guide adds that a fourth mode is downloadable at registration, giving four modes with two variations each3.
The Chorus Brigade mode mirrors what Delicious Audio calls "the legendary first-ever BOSS chorus, the CE-1 Chorus Ensemble"3. Universal Audio introduced the chorus alongside the rest of its first UAFX trio, announced earlier in the year and launched back in January, with the Astra as the company's big sibling multi-modulation pedal in the range5.
The controls
The Astra's six knobs are arranged in two rows. The top row has controls for Speed, Depth and Intensity, and the bottom row for Shade, Shape and Mode1. There are also three mini-switches: one to choose the type of effect, one to Store the preset, and an A/B variation switch1.
| Control | Row | What it does |
|---|---|---|
| Speed | Top | Rate of the modulation effect1 |
| Depth | Top | Depth of the modulation effect1 |
| Intensity | Top | Intensity of the effect1 |
| Shade | Bottom | Shading control1 |
| Shape | Bottom | Shape control1 |
| Mode | Bottom | Mode control1 |
The two footswitches handle effect on/off and preset access, and the pedal's dual processors allow a saved preset to be switched over while the pedal is running on a different setting1.
Presets and the A/B switch
Saving a preset is done with the Store mini-switch. Gearnews's reviewer described the process: "I set the Speed again, and this time held the Store switch down a bit longer. A green light blinked over the Preset footswitch"1. Holding the Store switch down longer saves the setting, confirmed by that blinking green light1.
The A/B variation switch selects between the two variations of the chosen mode, and the effect-type switch moves between Chorus Brigade, Flanger DBLR and Trem 651.
The Astra needs a 9V DC 400mA supply, which is sold separately4. That current draw is high enough that a battery or a shared daisy-chain output is not the way to run it; plan a dedicated supply output.
What reviewers said
Gearnews's reviewer found the UAFX pedals easy to use and very intuitive, and said that when put up against other comparably priced units, the three pedals have a lot on offer1. On preset switching, the reviewer reported: "The switching was seamless and, with a little bit of fiddling, the sound was close enough for me"1.
Comparing the Astra with the NEO Instruments micro Vent 16, the same reviewer concluded that for a little extra coin the UA Astra offers more features and can be hooked up to a computer for even more options1. Guitar World's buying guide summed up the effects quality: "The quality of the effects, as you'd expect from UA, is simply stunning and we especially loved the chorus mode"4.
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Questions
What effects does the UAFX Astra have?
The Astra offers three modulation effects: Chorus Brigade, a bucket brigade chorus based on the BOSS CE-1; Flanger DBLR, a bucket brigade flanger and phaser based on MXR's rackmount unit; and Trem 65, a vibrato based on classic vintage 60s Fender amps. Each setting has secondary modes such as Vibrato and Doubling, and a fourth mode is downloadable at registration, giving four modes with two variations each.
Is the UAFX Astra stereo?
Yes, the Astra is stereo. It has two inputs and two outputs, plus a USB-C connection for hooking the pedal up to a computer for additional options.
Does the UAFX Astra come with a power supply?
No. The Astra requires a 9V DC 400mA power supply, which is sold separately. Because of the 400mA current draw, a standard daisy-chain supply shared with other pedals may not be suitable.
Can you save presets on the UAFX Astra?
Yes. You save a preset with the Store mini-switch: set the sound, then hold the Store switch down, and a green light blinks over the Preset footswitch to confirm the save. The pedal's dual processors let you switch to a saved preset while running the pedal on a different live setting.
What does the A/B switch do on the Astra?
The Astra has three mini-switches: one to choose the type of effect, one to Store the preset, and an A/B variation switch that selects between the two variations of the chosen mode.
What is the Brigade chorus mode based on?
The Chorus Brigade mode mirrors the BOSS CE-1 Chorus Ensemble, described by Delicious Audio as the legendary first-ever BOSS chorus. Universal Audio later released a dedicated compact pedal of the same effect, the UAFX Brigade Chorus.
Sources (5)
- Review: UAFX Golden Reverberator, Starlight Echo Station and Astra Modulation Machine, gearnews.com, 2021-04-04
- Universal Audio Announces UAFX Effects Pedals, Premier Guitar, 2021-01-27
- Best Pedals For Synths: Multi-Modulation Stompboxes, Reviewed, Delicious Audio, 2023-11-02
- Best modulation pedals: our pick of the best mod effects, Guitar World, 2023-06-02
- New Pedal: Universal Audio UAFX Brigade Chorus, Delicious Audio, 2023-11-06
