The Astrospurt is a phaser pedal from KMA Machines, a company based in Germany. It is a four-stage JFET phaser, meaning its phase shifting is done in four stages using JFET transistors, the approach used in many classic phaser designs. The pedal on this page is a revamped version of the original Astrospurt, which KMA Machines introduced in 2014; the new version was sent to Pedal of the Day for review in January 20211. Guitar.com, in an interview with KMA's Enrico Preuss, described it as "a four-stage JFET phaser"2.
Pedal of the Day summed it up as "a wild phaser pedal," writing that "the Astrospurt covers all the spacey, dizzy, wobbly sounds you could possibly want…and then some"1. If you are new to the effect, phasers sweep a notch filter through your signal to create that familiar swooshing movement; our Phaser Pedals page covers the type in general.
Controls
The Astrospurt's control set goes beyond the speed and depth knobs of a basic phaser, adding a level boost, a wet/dry blend and a noise element you switch in when you want it1.
| Control | What it does |
|---|---|
| Spurt | Sets the phase range, from long and swooshy to fast and choppy, with all points in between |
| Depth | Controls how deep and present the phase sound is |
| Emph | Adds elements of semi-controlled noise into the mix, active only when the toggle below it is switched on |
| Signal | Sets your effect level boost |
| Mix | Blends your wet and dry signals |
A lone toggle switch below the Emph control activates the Emph effect1.
The Emph noise element only sounds when the toggle switch below the Emph control is engaged, so it is off by default1.
What reviewers said
Pedal of the Day's 2021 review found the pedal easy to live with: "Easy to use but also incredibly versatile," with the reviewer noting it worked "great on its own or teamed with a fuzz or distortion pedal, covering all modulation needs overall"1. That pairing matters in practice: a phaser placed before a fuzz or distortion pedal reacts differently than one placed after, and the Mix control gives you a way to keep the phased signal from overwhelming your drive tones.
Where it sits in KMA's range
The Astrospurt is the compact four-stage entry in KMA Machines' phaser line. The maker also builds the larger KMA Machines Horizont JFET Stereo Phaser, a stereo phaser with more routing options, and the original Astrospurt Phaser from 2014 that this pedal revises1.
Videos
KMA Machines
The Pedal Zone
Reverb
Questions
What does the Emph control do on the Astrospurt?
Emph adds elements of semi-controlled noise into the mix, according to Pedal of the Day. It only comes into play when you flip the lone toggle switch below the Emph control, so the noise element is something you bring in deliberately rather than something always running under the phase sound.
Is the KMA Astrospurt a four-stage phaser?
Yes. Guitar.com described the Astrospurt as a four-stage JFET phaser, and the pedal's full name carries that designation. It is a revamped version of the original Astrospurt phaser that KMA Machines introduced in 2014.
What does the Spurt knob control?
Spurt sets the phase range, which Pedal of the Day describes as going from long and swooshy to fast and choppy, with all points in between. In practice it is the control that takes you from slow, sweeping phase moves to quick, rhythmic ones.
Does the Astrospurt have a mix control?
Yes. Alongside Signal, which sets your effect level boost, the Astrospurt has a Mix control that blends your wet and dry signals. That lets you set how much of the phased sound sits against your clean tone rather than replacing it.
Sources (2)
- KMA Machines Astrospurt 4-Stage JFET Phaser, Pedal of the Day, 2021-01-04
- Interview: Enrico Preuss of KMA Audio Machines, guitar.com, 2019-03-11
