The Uni-Vibe effect is something of a mystery, in the sense that everybody’s heard it but hardly anybody seems to be sure what it actually is. What we do know is that this throbbingly phasey modulation effect, first concocted by Shin-ei in Japan over half a century ago, is a bit of a classic.

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ThorpyFX chief Adrian Thorpe is the latest builder to have a crack at updating the formula, in the shape of the ER-2 – named after a high-altitude research aircraft (rock ‘n’ roll!), and promising “Uni-Vibe perfection” but with added flexibility.

Some Uni-Vibe pedals – notably the underrated Voodoo Lab Micro Vibe – make do with just two knobs; others – like the not-exactly-underpriced Cornerstone Aquarium – give you all sorts of variables to play around with. The ER-2 sits somewhere in the middle, expanding the basic control set of speed and intensity with a mysterious knob marked ‘offset’ and another for output level. As a bonus, the usual ‘vibrato/chorus’ toggle has become a second footswitch.

This being a Thorpy, the high-walled aluminium enclosure is tough enough to survive being dropped from a cruising ER-2 and the internal construction appears to be of equally high quality. It is, of course, a true optical vibe, creating its modulation with a pulsating bulb surrounded by four light-dependent resistors.

In Use

My usual procedure when testing a pedal of this type is to give the vibrato mode a quick spin then flip immediately to chorus, which is where the ‘real’ Uni-Vibe tones live. But in this case I’m finding that difficult – because the first mode is way more addictive than it has any right to be.

It’s normal that this effect should be a little more complex than pure up-and-down pitch vibrato; but there’s an extra richness to this pulsating wobble that, at faster settings with the intensity set down around nine o’clock, is strikingly pretty. Who needs chorus mode anyway?

What you do get when you hit the left-hand footswitch is a straight-up Uni-Vibe, nailing that uniquely chewy swirl without any obvious coloration to the overall EQ balance. With a warmer-voiced amp you might notice a slight thinning-out of the low end in this mode; that makes the ER-2’s clean vibe tones a little less cuddly than some, but can give pleasing bite to an otherwise woolly fuzz. Feel free to test this with a Jimi-style mangling of The Star-Spangled Banner.

That offset knob changes the way the bulb ramps up; the effect is minimal except at slower speeds, where you can hear a difference in the shape of the modulation: at minimum it arcs around smoothly like a phaser; at maximum it throbs with a quirky asymmetry. If you’re familiar with the Dawner Prince Viberator and its shape control, this is the same kind of deal.

Things can get motorboaty if you push the intensity past noon, but it’s such a powerful effect even at much lower settings that this is hardly likely to be an issue. It’s not cheap, but the ER-2 is good vibes all the way.

$323/£305, thorpyfx.com

Like this? Try these

• Cornerstone Aquarium £445
• Dawner Prince Viberator £255
• EarthQuaker Devices The Depths V2 £229