Music & Entertainment

How to Use Chorus Pedals in Guitar Playing With Tom Morello

Written by MasterClass

Mar 28, 2019 • 4 min read

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Tom Morello Teaches Electric Guitar

In the early days of the electric guitar, there was only one way to affect its sound: turn up the volume on the amplifier until it started distorting. Later, amplifiers added effects like EQ, reverb, and tremolo—the latter of which is sometimes incorrectly labeled as “vibrato.”

True vibrato involves slightly changing the pitch of a sounded note. This was best captured using rotating speakers, like those manufactured by the Leslie corporation. Out of the vibrato effect came the chorus effect.


What Is the Chorus Effect in Guitar Playing?

A chorus effect is produced via an audio process wherein a sound is re-sampled just milliseconds after the initial note is played. These sounds, vibrating ever so slightly out of sync with one another, create a textured effect and the illusion that a “chorus” of instruments is playing, rather than just one.

What Is a Chorus Amplifier?

A chorus amplifier is an amplifier that includes a built-in chorus effect that a player may choose to engage (although it’s also possible to play with the effect turned off). A number of amplifiers feature a built-in chorus effect, including the Fender Princeton Chorus and the Peavey Stereo Chorus. But by far the most legendary chorus amplifier is the Roland Jazz Chorus series, which covers a number of solid state amplifiers of varying sizes.

The Roland Jazz Chorus features a toggle switch between a chorus effect and a vibrato effect (recall that they operate on similar principles). These amplifiers were massively popular in the late 1970s and ’80s rock scene, with famous practitioners including Andy Summers of The Police, Robert Smith of The Cure, and Steve Hackett of Genesis.

What Is A Chorus Pedal?

Today’s guitar player is most likely to encounter a chorus effect via a stompbox chorus pedal. These bottle up the magic of the large and heavy Roland Jazz Chorus amp into a compact, lightweight stompbox to put on your pedal board. There are many different models available—some are digital chorus pedals and some are analog chorus pedals.

A Brief History of Chorus Pedals

The first mass market chorus pedal was the CE-1 by BOSS, a legendary Japanese manufacturer of stompboxes that is now owned by Roland, creators of the Jazz Chorus amp. BOSS now offers a CE-2 pedal and it only has two controls:

  • Rate, which controls how “close together” or “spaced out” the guitars of the fake ensemble will sound.
  • Depth, which controls the intensity of the effect.

BOSS chorus pedals can be heard on all sorts of ‘80s new wave and ‘90s funk.

Where to Place a Chorus Pedal In Your Effect Chain

Chorus is a modulation effect, and as such, it should be placed fairly late in your pedal chain. It should come after a wah pedal, compression pedal, overdrive pedal, and distortion pedal, but before your delay pedal, tremolo pedal, or reverb pedal. Because chorus and vibrato are nearly the same effect, they can go in either order when placed next to each other.

Some chorus pedals include a mild buffer to boost the level of a guitar’s audio signal, and other such pedals are “true bypass,” which means no such buffer is present. A true bypass tuner may be appropriate if there are very few pedals in your signal chain. But players with a lot of pedals will likely benefit from a mild buffer; without such buffers, there will be a noticeable drop in volume by the time the audio signal reaches the amp.

tom morello playing his acoustic guitar


Tom Morello’s Tips for Using Your Chorus Effects Pedal

Tom Morello, whose guitar playing has been heard via Rage Against the Machine, Audioslave, The Nightwatchman, Bruce Springsteen, and more, offers these tips for playing with a chorus pedal:

  • Most chorus pedals have knobs for depth (controls depth of modulation) and rate (controls the speed of the modulation). Play with these two effects to add color or all-out weirdness.
  • Rate and depth set to halfway provide the characteristic chorus sound—perfect for dreamy chords and sparkling picking parts.
  • Enhance lead tone: Michael Angelo Batio is known for using a small amount of chorus in his lead tone to thicken it up and add color.
  • This can be done by turning down the effect level control (if your pedal has one), or by turning down the rate and depth controls.
  • Depending on your chorus pedal, turning the rate up about halfway and depth about 3⁄4 of the way will produce a semi-effective Leslie rotating speaker effect. Depending on your chorus pedal’s depth and rate control range, if you turn these controls all the way up, you will pass the “Leslie Effect” and move into warbling madness.
  • Experiment with depth control set to 0 and rate set to 10, and vice versa.

The Best Chorus Pedals On the Market Today

The Electro-Harmonix Small Clone is a popular competitor to the Boss CE. It also contains a Rate knob, with a smaller switch for Depth. To hear the Small Clone in action, check out Kurt Cobain’s guitar solo on “Smells Like Teen Spirit.”

TC Electronic is a Danish company famous for its digital stompbox pedals. The TC Electronic Corona chorus pedal (named for the site of the original Fender factory) is highly customizable. In addition to Rate and Depth, it features a Tone knob and a knob for overall “FX Level”—allowing the player to also dial in some dry guitar signal to mix with the chorus effect.

For those with a slightly larger budget, high-end pedal maker Strymon offers a combo chorus/vibrato unit—much like the combo effect on the original Roland Jazz Chorus. The Strymon pedal, called the Ola dBucket features five control knobs, three filtering modes, and the option to use chorus, vibrato, or a mixture of both.

If you can push your budget even further, Strymon also makes an incredibly powerful modulation pedal called the Mobius. The Mobius can produce over a dozen effects — chorus, vibrato, rotary speaker simulation, and much more—and it features both stereo inputs and stereo outputs.

Learn more about using chorus pedal—and other pedal—effects from Tom Morello here.