Strymon UltraViolet: A Classic Effect Gets a Modern Upgrade

Few effects are as closely tied to an era of rock music as the Uni-Vibe, the whooshing, buoyant effect that defined the sound of late-1960s psychedelic rock and into the darker and experimental 1970s. The original, lightbulb-equipped Uni-Vibe by Shin Ei was a go-to stompbox for Jimi Hendrix, David Gilmour, Robin Trower, and countless other guitarists of the era—which is why they’re a four-figure Holy Grail for pedal collectors today.

For the rest of us who want an authentic Uni-Vibe sound without breaking the bank, Strymon has released the UltraViolet Vintage Vibe, the most accurate recreation of the iconic vibe sound yet. This pedal is far from just the old circuit in a new box because it also has some much-welcomed updates and features for easier handling and even more sonic possibilities.

Let’s dive into the UltraViolet and discover the many otherworldly sounds it has in store. But first, check out this demo video from Vintage King's own Kevin Schuck!

What’s a Uni-Vibe?

First things first, what exactly is a Uni-Vibe? If you’ve heard one before, then you’ll know that it’s an odd duck in the pantheon of guitar effects (which is why it’s so loved).

The original Uni-Vibe unit was developed in the 1960s by audio engineer Fumio Mieda and was first manufactured by the Japanese company Shin Ei. The company initially marketed the pedal as a stage-friendly, speaker-free emulation of a Leslie-style rotary speaker, and while it didn’t really accomplish that goal, it did have a sound all its own: A whooshing, cascading, bubbling oscillation that was perfect for the emerging Summer of Love. It was this first version of the Uni-Vibe that Jimi Hendrix used onstage at Woodstock, a moment that defined the late-1960s rock sound and the Uni-Vibe’s place in that canon.

Contrary to popular belief, the Uni-Vibe isn’t exactly a phaser (a la an MXR Phase 90), but is pretty much its own category of effect—a vibe, if you will. Vibe pedals (like the UltraViolet) can make a good phaser, but that is just one of the many sounds they can produce. The source of the Uni-Vibe's mojo is its internal lightbulb, which creates that lethargic push and characteristic swoosh sensation.

However, similar to early-age guitar pickups, there were slight sonic differences even between Uni-Vibes of the same era and origin. In reality, the golden-age Uni-Vibe “sound” was actually a collection of wildly varying tone profiles. That’s where the UltraViolet comes in, as it’s designed to capture not just an approximate Uni-Vibe sound, but all types of potential Uni-Vibe sounds from that treasured era (and then some).

The Strymon UltraViolet

While there’s no lightbulb in the circuit, the UltraViolet is equipped with a brand-new vibe algorithm that captures all of the quirks, responsiveness, and interplay between components that made the original Uni-Vibes so unique. It’s probably the most accurate vibe sound you’ll find in a pedal of this size (and price tag), but it also packs plenty of original tones as well thanks to its expanded controls.

Blend and Bias

The most unique new controls on the UltraViolet are the Blend and Bias controls, which unlock a wide range of variations on the vibe sound. The Blend switch changes up the wet-dry ratio for dramatic shifts in your tone without fiddling with multiple knobs, giving you three different shades of vibe at the flip of a switch.

Chorus: A 50/50 mix for whooshy, trippy tones that are perfect for the classic 60s Uni-Vibe sound.
Blend: A more subtle 70% dry, 30% wet mix designed specifically for the UltraViolet, this mode is a great base to construct square-wave tremolo, rotary speaker-style warble, and more.
Vibrato: This 100% wet mix is a frequency-dependent phase vibrato that’s particularly responsive to the Bias and Intensity controls.

Speaking of, the Bias switch sets the center frequency for the all-important LFO sweep. This is where the lightbulb comes into play on the original Uni-Vibe circuit: The LFO sends a constantly varying voltage to the bulb, causing it to repeatedly change brightness. That change then affects light-dependent resistors, which then impact the phasing filters, which finally results in the titular “vibe.”

As we mentioned earlier, the early Uni-Vibe pedals had a wide array of tonal differences, the common cause being the bulbs’ max brightness—brighter bulbs made for smoother shapes and more emphasis on the high end, while dimmer ones resulted in darker, jagged tones. Which variation you got back in the day was a lottery, but thankfully, the UltraViolet’s Bias switch lets you choose between three versions on the fly:

Low: brings out the pedal’s more mellow, pulsating characteristics that are ideal for tremolo-forward effects.
Mid: Right in the sweet spot for classic, Hendrix-esque tones that we know and love.
High: Creates a smoother shape and wider frequency sweep that will sound familiar to Pink Floyd fans.

These two switches interact well with one another to bring out a massive range of sonic outcomes outside of the typical vibe sound, like classic phaser, pulsing trem, subtle rotary warble, and more.

Intensity and Volume

The UltraViolet also features the traditional Uni-Vibe control scheme: Speed, Intensity (aka Depth), and Volume. But even these typical features have some tweaks for greater control and versatility.

The Volume knob gives your signal up to a 4db boost when the pedal’s activated, which makes for a chunky, solo-friendly boost on its own. Just switch to Vibrato mode and bring the Intensity knob to zero for a straight-ahead, edge-of-breakup tone. In fact, the rolled-off Intensity knob also has another use other than muting the vibe: In Chorus or Blend mode with Intensity at zero, the pedal transforms into a subtle yet off-kilter phase EQ effect, with the Bias acting as a dark/bright switch.

In general, the Intensity knob sports an expanded control range at lower speeds, fixing the original Uni-Vibe circuit’s well-known quirk of automatically increasing the LFO amplitude at higher speeds. This small change evens out the effect’s range for a more consistent sweep from one end of the knob to the other and makes for more available sonic options at lower speeds.

I/O Routing and MIDI Options

Rounding out UltraViolet’s impressive features list is everything happening on top. The High impedance, ultra-low-noise input is equipped with a JFET preamp, which ensures maximum touch sensitivity and responsiveness once you stomp the pedal on (and it’s true bypass when off, by the way).

Speaking of the jacks, don’t be fooled by the standard-looking I/O jacks. Grab some TRS cables and flip the I/O mode selector from Mono to Stereo to create ping-ponging waves, immersive whooshing, head-spinning trem, and more. If you don’t have TRS cables handy, then set the mode selector in the middle position for Mono-In/Stereo-Out mode.

Finally, there’s the MIDI of it all: The UltraViolet supports MIDI implementation with 300 presets available right out of the box, making it a seamless addition to your MIDI rig or pedalboard. With the EXP/MIDI jack or the USB-C input, you can remotely change or automate the pedal’s settings via an external controller or DAW for maximum efficiency in your creative workflow. For a more old-school setup, you can also hook up an expression pedal for controlling the speed setting or an extra footswitch for tap tempo or preset recall.

If you’re interested in purchasing the new UltraViolet vintage vibe, or any other pedals from Strymon, contact a Vintage King Audio Consultant via email or by phone at 866.644.0160.