Redefining the humble tremolo... In purple! Words by Steve Henderson.

Rocker pedals have been done, that’s for sure, and all manner of sound effects have been given the ‘variable real-time control’ treatment. The first two were the venerable wah pedal – way back in ’66 by the Thomas Organ Company – and the must‑have‑for‑every-guitarist volume pedal; DeArmond was producing those in the ‘40s.

Tremolo, too, has been a go-to effect for a long, long time – mostly for organ players, but guitarists soon enough adopted it just in time for the surf music scare of the early ‘60s. So, what sets Ernie Ball’s Expression Tremolo rocker pedal apart from the crowd?

Well, to start with, it’s purple. That alone makes it an eye-catcher, but the Expression Tremolo also has small footprint, so it won’t take up much more real estate that a normal stomp box. In fact, it’s only about 50 percent larger than a Boss compact pedal.

Next, like all EB pedals, it’s built superbly – it’s made from aircraft‑grade aluminium, and bulletproof like no other brand (look at all the players still using their original Ernie Ball volume pedals after 40 years). Also, the treadle action feels smooth, controlled and expressive, with just the right amount of resistance to make the player work a little. Best of all, the tremolo effect is well thought out, with options that deliver some unique sounds along with the classics.

The really unique feature of the Expression Tremolo is that it can be used as a normal stomp box – the treadle acts like a normal on/off switch – or as a rocker pedal. Because of this, you don’t actually need to rock the treadle to produce a trem effect. Set the wave form dial to the required shape (I initially chose a classic sine wave), and with the treadle pushed all the way forward, adjust the depth and rate to suit.

The Expression Tremolo produces a rich, almost three-dimensional trem effect, without thinning out the bottom end. Now, push the end of the Depth knob (an LED lights up) and this assigns that particular parameter to the treadle – which is now an expression pedal rather than just an on/off switch. The depth value is now adjustable, in real-time, from zero to whatever.

Now turn off the Depth knob switch and do the same with the Rate knob – use it either as a fixed control or as a completely variable parameter. This means that pushing the treadle forward increases the speed of the trem effect – very useful as an expressive device.

Can you have both parameters controlled by the treadle at the same time? Absolutely, and this blends from no effects at all to an extreme chopper. The ‘combined parameter’ effect sounds super cool throughout the sweep and never thins out, gets mushy or creates any kind of harmonic clash. It remains defined and purposeful.

There’s a built-in bonus in the form of a sweet spring reverb effect, just to put a little extra grease on the tracks. It’s a simple one-knob device that operates with the treadle, but not by itself. It’s a warm tone that adds an extra depth to the sound, rather than the shimmer that you might find in, say, a plate reverb effect. It’s a great sound, but it could have had a switch to either assign it to the treadle or have it as an independent, always-on sound. The reason for this observation is simple: reverb is an environment more than an actual effect, and this doesn’t change from song to song.

As for the trem effect options, the Expression Tremolo offers some pretty cool sounds. The ‘Ramp Up’ and ‘Ramp Down’ options are really interesting. If you’re after something a touch unusual – something with a unique vibe, but not completely weirded out – this may be just the ticket.

The ‘Sine’ and ‘Square’ waves are standard fare on most Tremolo pedals, but the ‘Harmonic’ option is a seriously useful, rich, chorus-y sine wave shape that can sound extreme, or even better, can back off to a more subtle and expressive sweep. This sounds great in conjunction with the built-in reverb.

The mechanics of the Expression Tremolo rocker function are solid and reliable, supported by 40 years of Ernie Ball rocker pedal experience. The Expression Tremolo is a road-ready tremolo unit that produces a refined, harmonically rich sound – perfect for the stage (compact and reliable) or studio (super-quiet).

It has all the control that you need, and doesn’t clip off the high treble of low bass. It has more of a hi-fi-quality sound, rather than the slightly fuzzy Fender amp trem, which means it won’t impact on your basic amp tone. In fact, testing it with a variety of amps demonstrated its ‘transparency’ in that each amp’s inherent character remained the core of the guitar‑amp partnership, with the Expression Tremolo adding its Hendrix-approved texture without being the complete centre of attention.

And, it’s worth experimenting with signal chain placement: I alternated an old Boss DS-1 before and after the Expression Tremolo for a variety of tones that were all useful and fun to mess with.

The purple livery is certainly distinctive – nobody will confuse this with their Ernie Ball Volume Pedal. All in all, the Expression Tremolo is a worthy addition to the venerable Ernie Ball line, and a useful addition to any professional musician’s pedalboard. Plus, it’s an absolute hoot to use.

• ​Multiple selectable waveforms
• ​Treadle-controlled rate and depth
• ​Built-in spring reverb
• ​Super solid build values
• ​LED indicators

•​ Great fun to play
•​ Professional craftsmanship
•​ Great range of sound options

•​ I wish the Reverb would stay on

CMC Music

Ph: (02) 9905 2511