Guyatone GST-UO5 Ultron

This pedal shows how versatile an envelope filter can be

Without a touch of wah, '70s porn soundtracks just wouldn't be the same. It doesn't matter how good/bad the action is, whack on a wah pedal fed by some Hendrix-style guitar and everything just seems to, er… slip into place, so to speak.

Wah has come a long way since those halcyon days of big moustaches and dubious plotlines and at first glance the Guyatone Ultron couldn't look further removed from those brick-like pedals of the '70s.

It's a lightweight but well-built beast that looks like it would be happier in the safe confines of a recording studio than onstage under a Converse trainer – those little panel switches and LED display should be treated with respect!

The Ultron's circuitry is based on the classic Mu-Tron III envelope filter of the 1970s and offers three main types of effects.

Two of them, as discussed in the pornographic opening paragraph, are wah effects – auto and manual. The remaining effect is an envelope filter controlled by the intensity of the input signal.

It's no surprise that Funk legend Bootsy Collins endorses the Ultron. Run any kind of bass signal through that envelope filter function and you'll see why the pioneering bassist describes the Ultron as "Da Bomb!" How's that for an endorsement?

Crashing back to Earth for a second, the cool thing about this pedal is that it combines the best bits of digital and analogue technology. It features a totally analogue audio path, which will please the vintage tone nuts, partnered with the functionality of digital.

So it's easy to adjust parameters quickly, and switching is silent enough to make the Ultron welcome in any recording studio. The front panel is intuitive, and if you're one of those people who hates reading operation manuals then you'll get a long way before you need to reach for the little book.

Sounds

The problem with many wah units these days, including guitar effects pedals, is that they sound so damned weedy – a wah should sound fat and juicy. The Guyatone folk have obviously given tone a great deal of thought because (with apologies to another Japanese manufacturer) the Ultron sounds totally boss.

Both the Auto-wah and envelope filter functions are self-contained effects, while the Manual-wah mode requires the use of an optional expression pedal (Guyatone recommends that you use only the Boss FV-5, £49).

Unsurprisingly for a product that pays tribute to the Mu-Tron III the Ultron's envelope filter excels when you play 'choppy' Funk riffs, making it perfect for rhythm guitar tracks, slap bass and the kind of keyboard parts that Stevie Wonder made his own on songs like Higher Ground.

I also love the Auto-wah and the way it complements the instrument's tone rather than smothering it.

The Guyatone Ultron is not intended for guitarists who want to emulate only Jimi Hendrix. Oh no. The Ultron is for those musicians – be they guitarists, keyboard players, bassists or producers– who want an array of top-class filter effects handy in an easy-to-use package.

MusicRadar Rating

4 / 5 stars
Pros

Meaty wah!

Cons

It's not cheap.

Verdict

You can't move for envelope filters these days, but few can boast the warmth that the Ultron delivers.

Available Inputs

1/4 Inch Jack

Available Outputs

2x1/4-inch jacks

Battery/Adaptor Type

DC adaptor

Depth (mm)

55

Description

Optical envelope filter.

Features

Notch, low-pass, band-pass, high-pass filter types. Oscillator waveforms: Triangle, sawtooth, reverse sawtooth, square 1, square 2, square 3.

Height (mm)

188

Weight (kg)

685

Width (mm)

120

Review Policy
All MusicRadar's reviews are by independent product specialists, who are not aligned to any gear manufacturer or retailer. Our experts also write for renowned magazines such as Guitarist, Total Guitar, Computer Music, Future Music and Rhythm. All are part of Future PLC, the biggest publisher of music making magazines in the world.