TECH 21, THE COMPANY
Tech 21 was formed by a guitarist possessing the unusual combination of a trained ear and
electronics expertise. In 1989, B. Andrew Barta made his invention commercially available to
players and studios around the world. His highly-acclaimed
SansAmp™ pioneered Tube
Amplifier Emulation in professional applications for recording direct and performing live, and
created an entirely new category of signal processing. There have since been many entries
into this niche, yet SansAmp continues to maintain its reputation as the industry standard.
With a full line of SansAmp models, Tech 21 also offers effect pedals and MIDI products, as
well as “traditional” style amplifiers for guitar and bass. Each product is thoughtfully and
respectfully designed by B. Andrew Barta himself with the player in mind. Our goal is to pro-
vide you with flexible, versatile tools to cultivate, control, refine and redefine your own indi-
vidual sound. Tech 21 takes great pride in delivering consistent quality sound, studio to studio,
club to club, arena to arena.
PRODUCT OVERVIEW
Derived from the careful study of ‘70s choruses, the Boost Chorus pedals combine studio-grade
performance with unique effect combinations to create thoroughly modern options. Each offers
an unusual amount of flexibility to achieve a variety of choral effects, including any array of
entertaining, yet cleverly useful, never-before-heard sounds.
The different designs address different and inherent needs of guitar and bass players. However,
either pedal can be used on either instrument, as well as any number of other instruments.
Experimentation is always encouraged!
The Boost Chorus features a Pre-Delay control, which alters the delay range of the chorus
effect. For the Bass Boost Chorus, we took a different approach. It features a Detune control
to adjust the pitch of the choral voicing, adding sonic girth to create thick, lush, bass-compati-
ble
chorus. While Speed and Depth controls add modulation, you can set them at minimum to
preserve the fundamentals. This avoids that queasy, seasick feeling typically associated with tra-
ditional chorus pedals when used on bass.
Both Boost Chorus pedals feature a Multi Voice switch, which increases dimension with addi-
tional choral voicings.
As with each Tech 21 product, the controls are designed to give you the flexibility to obtain
your desired sound. It is our hope that the Boost Chorus and Bass Boost Chorus will be use-
ful tools for stimulating your creativity and, ultimately, providing the inspiration to play your
best.
THE INS AND OUTS
1/4” INPUT:
1megOhm high impedance input, same as traditional tube amps. Also
switches battery power on/off. To avoid battery drain, unplug when unit is not in use.
1/4” OUTPUT:
1kOhm low impedance output drives long cables without loss of signal
integrity, even in bypass.
SIGNAL LEVEL TO INPUT/CONNECTIONS
The Boost Chorus pedals are designed to accommodate instrument level signals to the Input, such
as the output of a guitar/bass, distortion pedals, etc. For normal operation, signal level to Input
should be close to that of a standard electric guitar/ bass (approx -10dBm / 250mV). Line level sig-
nals will not damage the Boost Choruses, however the resulting sound may not be particularly
desirable.
GUIDE TO CONTROLS - Boost Chorus
PRE-DELAY
Sets the delay time of the chorus, ranging from 0-50 milliseconds, giving you a wide range of
flexibility. Below one o’clock emulates a 512-stage bucket brigade. Above one o’clock emu-
lates a 1024-stage bucket brigade and beyond.
0-10 = flanging/vintage chorus
(512-stage bucket brigade)
10-30 = ‘80s chorus
(1024-stage bucket brigade)
30-50 = doubling/slapback echo
(1024+-stage bucket brigade)
Multi Voice
Adds additional choral voicings. To engage, push the switch in. This creates 3 choral voices
with 90 degrees of separation that “chase” each other. Rather than hearing a typical sweep,
this gives you a more natural choral personality and is more compatible with distortion.
GUIDE TO CONTROLS - Bass Boost Chorus
DETUNE (Bass Boost Chorus)
Shifts the pitch of the choral voicing up or down. At unity (12 o’clock), there is no pitch
shifting. The Detune control enables you to have a chorus sound without any modulation
when Speed and Depth are at minimum. Note: This control functions differently depending
on the orientation of the Multi Voice switch:
In Single Voice mode: As you increase Detune, the pitch goes up/sharp. As you
decrease, the pitch goes down/flat.
In Multi Voice mode: Detune controls the pitch of 2 voices. As you increase Detune, one
voice goes up/sharp and one voice goes down/flat. As you decrease, one voice goes down/flat and
one voice goes down/flat in smaller increments.
Detune Setting Tip: for vintage chorus sounds, set Detune at 12 o’clock and use Speed
and Depth to add modulation.
GUIDE TO GENERAL CONTROLS
SPEED
Controls the speed of the modulation from .2 Hz to 10 Hz.
DEPTH
Controls the depth of the modulation. A minimum setting will give you a subtle effect. As
you increase, it will become more and more “wobbly.”
TONE
100% analog circuit. Affects the tone of the delayed signal only. Unity gain is at the indicator
arrow and will have no effect on the signal. Increasing the setting will give you a treble boost
for a snappy ’80s chorus sound. Decreasing the setting will give you a treble cut, yielding a
darker analog chorus sound.
MIX
100% analog circuit. Controls the ratio of direct and modulated signal. While most chorus
pedals provide a preset 50/50 mix ratio, the Tech 21 Mix control offers a sweep from 100%
dry to 100% wet for a vibrato effect. This gives you more flexibility when you want to run
through a parallel effects loop without annoying phase cancellation.
LEVEL / BOOST
100% analog circuit. Not commonly found on chorus pedals, this control adjusts the overall
output level to ensure against the typical drop in volume when the pedal is engaged. Increasing
from unity gain provides additional boost, up to 3dB or 9dB depending on your other settings.
Level tip: If you have a 100% wet signal going through a parallel effects loop, use the Level
to adjust the mix of dry and effected signal.
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