Tech 21 Boost Chorus Bass

The Tech 21 Boost Chorus Bass is a chorus pedal built specifically for bass, released by Tech 21 on May 19, 2011 alongside a guitar version, the standard Boost Chorus¹. It is part of Tech 21's answer to a familiar problem: chorus pedals designed for guitar can make a bass sound seasick and wash out the low notes. Tech 21 says the Boost Chorus Bass "avoids seasick tones, and badgers, through a specially-tailored design" aimed at bass amps².

What sets it apart from most bass choruses is the Detune control. Where the standard Boost Chorus has a Pre-Delay control, the Bass version replaces it with Detune, which adjusts the pitch of the choral voices. Tech 21 describes the result as adding "sonic girth to create thick, lush, bass-perfect chorus"². Because Detune works independently of the modulation controls, you can use it as a thickener with the chorus motion turned completely off.

A bass chorus with boost and a Detune control

The pedal shares its control set with the standard Boost Chorus, including the Multi Voice switch, and differs mainly in having the Detune control in place of Pre-Delay². The core idea is that Speed and Depth add the modulation, and at their minimum positions your fundamental notes are preserved⁵. That matters for bass players who want chorus color without losing the note definition that holds a mix together.

The Detune control is the bass-specific twist. Premier Guitar's reviewer explained that "by introducing a Detune control that adjusts the secondary pitch of the signal, Tech 21's Bass Boost Chorus is able to" create a thicker chorus effect while preserving the fundamental characteristics of each note⁶. In practice, Detune shifts the pitch of the second voice up or down, so the effect can range from a subtle doubling to a wide, lush spread⁷.

The Multi Voice switch adds another layer. Engaging it brings in additional choral voicings for what Tech 21 calls an Ensemble-style effect⁷. No Treble's Kevin Johnson noted that the switch "provides additional choral voicings" alongside the Detune knob⁴.

Tech 21 also published a set of sample settings for the pedal, which gives a sense of the range it covers²:

• Cure Bass
• Hooky
• Squire Harmonized
• Bass Chorus, no modulation
• Jaco Fretless
• Vibrato Bass
• Triple Voice Bass
• Infinite Flange
• Bass Thickener
• Subtle, Shimmer and Randy Rhodes settings for guitar²

The "Bass Chorus, no modulation" setting is the Detune control doing its job on its own, and the "Infinite Flange" and "Bass Thickener" names show how far the voicings can be pushed²⁷⁴.

The controls

Tech 21 says no fewer than six controls let players dial in the tone, speed and depth of the effect³. Four of them are knobs, one is the Multi Voice switch, and the pedal also carries a silent-switching, custom footswitch actuator¹.

The Level control is where the "boost" in the name comes from. Chorus can make a signal feel quieter, and Tech 21 designed Level to add boost back in as needed⁷.

Power and connections

The Boost Chorus Bass runs on a 9V alkaline battery, which is not included, or on an optional DC power supply, Tech 21 Model #DC2¹. The same two options were listed in the original 2011 press release¹.

The pedal uses buffered bypass rather than true bypass¹. Tech 21's position is that buffered bypass "eliminates the shortcomings associated with 'true bypass' (pops and clicks, and high-end loss when multiple pedals are connected together), as well as signal loss associated with other types of switching circuits"⁷. Players who run long chains of true-bypass pedals may see the buffer as a benefit; players who want the pedal fully out of the chain when off should note it is not a true-bypass design.

One connection limitation worth knowing: the Boost Chorus line has no stereo output, as MusicRadar's Trevor Curwen noted in his review of the standard model⁸. If you need a stereo chorus for two amps or a stereo rig, this is not that pedal.

What reviewers said

Premier Guitar reviewed the Bass Boost Chorus and framed its verdict around the player it suits: the pedal is recommended if "you seek an intuitive, great-sounding chorus pedal for electric bass"⁶. The review highlighted the Detune control as the design choice that lets the pedal thicken a bass signal without sacrificing the fundamental of each note⁶.

No Treble's launch coverage emphasized the same point from a bass player's angle, reporting that the Detune knob "adds girth by adjusting the pitch of the second voice, even when the Speed and Depth co"ntrols are at minimum⁴.

Questions