The Thermion Black Sun Analog Rotophaser is an analog pedal from Thermion that sets out to cover two related sounds in one box: the classic rotary speaker effect and the phaser. Thermion describes it as "the analog rotophaser capable of recreating the most classic rotary speaker sound," and Pedal of the Day, reviewing it in May 2021, heard a pedal that "combines classic rotary speaker sounds with experimental phaser options"12. If you have ever wanted a Leslie-style swirl or a deep, unusual phaser on a pedalboard, this is the category of pedal built for it, and it sits alongside other modulation effects such as chorus pedals and phaser pedals.
Where the rotophaser comes from
The rotary speaker sound goes back to cabinets like the Leslie, whose spinning speaker produces a swirling, Doppler-shifted tone. Pedal of the Day notes that players classically looked to units like a Fender Vibratone, the MTI Rotophaser and, of course, the Leslie rotating speaker cabinets for this sound, and that the Black Sun combines all that with those vintage units in a pedalboard-friendly enclosure2.
The Black Sun sits at a crossing point of two threads in modulation design: effects that chase the sound of a rotating speaker, and the phaser. Thermion's rotophaser brings both together in one pedal, and the sections below look at what that means for how it works and how it is controlled.
Delicious Audio's Christopher Scapelliti, covering the pedal in January 2019, wrote that it "might be the most detailed mono rotary speaker effect this side of lugging an actual Leslie to your next gig"3.
The controls
The Black Sun gives you what Thermion calls "total control over the oscillator," and the control set reflects that. The tempo controls set the two speeds and how the pedal moves between them, while the oscillator controls shape the character of the modulation itself1.
| Control | What it does |
|---|---|
| Speed G/R | Sets the green and red oscillation speeds, the pedal's two speeds1 |
| Shift G/R | Sets the green and red transition times1 |
| Multiplier | Sets a figure multiplier for the oscillation rate1 |
| Waveform | Oscillator control for the modulation waveform1 |
| Cycle | Oscillator control for the duty cycle1 |
| Depth | Oscillator control for the modulation depth1 |
| Two-band EQ | For dialing in the right tonal overtones to your sound2 |
The footswitch side carries the two speed modes. In Tap tempo mode, you tap the desired rotation speed; in Speed mode, the pedal shifts between the green and red oscillation speeds1. Because the two speeds are configurable and instantly switchable, you can set up, for example, a slow swirl and a fast one and move between them mid-song.
The Multiplier, Waveform, Cycle and Depth controls go beyond what a standard phaser offers. Pedal of the Day described them as controls that "open up the sonic playground for you to run through and experiment"2, which is worth knowing if you want a set-and-forget phaser: this one invites deeper tweaking.
What reviewers said
Pedal of the Day's verdict, from its May 2021 feature: "A versatile, exclusive effect with unique tone, the Black Sun combines classic rotary speaker sounds with experimental phaser options"2. The same review called the pedal "wonderfully modulated and full of surprises"2.
Videos
Thermion
TheGuitarGeek
Pedal of the Day
Questions
Does the Thermion Black Sun have tap tempo?
Yes. The Black Sun has a tap tempo mode where you tap the desired rotation speed, alongside a Speed mode that shifts between the green and red oscillation speeds. Pedal of the Day, reviewing the pedal in May 2021, noted that with two configurable and instantly switchable speeds plus tap tempo, there was not a lot the pedal would not do.
Is the Thermion Black Sun analog?
Yes. Thermion describes the Black Sun as the analog rotophaser, and the pedal's full name, the Thermion Black Sun Analog Rotophaser, carries the same designation. It is a stompbox-format pedal rather than a rack unit or digital multi-effect.
What is the Note Multiplier on the Thermion Black Sun?
The Note Multiplier is a tempo control that sets a figure multiplier for the oscillation rate. Together with the Speed G/R and Shift G/R controls, it shapes how fast the modulation runs and how the pedal moves between its two speeds. Pedal of the Day counted it, with Waveform, Cycle and Depth, among the controls that open up the pedal for experimentation.
How many speeds does the Thermion Black Sun have?
Two. The pedal stores a green oscillation speed and a red oscillation speed, set with the Speed G/R control, and can shift between them instantly. The Shift G/R control sets the green and red transition times, so you can shape how the pedal moves from one speed to the other.
What is the difference between a rotary speaker effect and a phaser?
A rotary speaker effect imitates the sound of a spinning speaker cabinet, such as a Leslie, while a phaser creates its sweeping, filtered character with an all-pass filter circuit. The two are related: according to Delicious Audio, a lot of modulation pedals were born out of not entirely successful attempts at simulating the effect created by a rotary speaker, with the phaser launched by the Maestro Phaser in the early 1970s. The Black Sun is built to do both.
Sources (3)
- Black Sun, Thermion (thermion.eu)
- Thermion Black Sun Analog Rotophaser, Pedal of the Day, 2021-05-25
- Thermion Black Sun Rotary, Delicious Audio, 2019-01-23
