BOSSCO EQ-20 Advanced EQ User manual

Thank you, and congratulations on your choice of BOSS EQ-20 Graphic Equalizer.
Before using this unit, carefully read the sections entitled: “USING THE UNIT SAFELY”
and “IMPORTANT NOTES” (p. 24–26; p. 2–3).
These sections provide important information concerning the proper operation of the unit.
Additionally, in order to feel assured that you have gained a good grasp of every feature
provided by your new unit, Owner’s manual should be read in its entirety. The manual should
be saved and kept on hand as a convenient reference.
Copyright © 2000 BOSS CORPORATION
All rights reserved. No part of this publication may
be reproduced in any form without the written
permission of BOSS CORPORATION.
Main Features
●
This is a 10-band graphic equalizer that lets you vary levels by +/-15 dB from 30 Hz to 12 kHz.
●
You can use pedal operations to switch between “MANUAL,” which offers equalization based
on the positions of the controls; and “MEMORY,” which can store nine different equalization
setups in memory. The superior functionality of the unit really becomes evident at those times
when you need to change settings instantly, such as for lead guitar, for cutting, or for booster.
● Features an LCD screen for graphic display of the equalization setups stored in “MEMORY.”
The screen has a handy backlit for use on stage and in dark locations.
● Supports guitar amp send/return (+4 dBu input and output). This makes preamp sound
correction possible.
● Uses a diecast body offering outstanding strength and durability.
● Can run on battery power (six AA type).

2
IMPORTANT NOTES
In addition to the items listed under “USING THE UNIT SAFELY” on page 24, please read
and observe the following:
Power Supply: Use of Batteries
301
• Do not use this unit on the same power circuit with any device that will generate line noise
(such as an electric motor or variable lighting system).
302
• The AC adaptor will begin to generate heat after long hours of consecutive use. This is
normal, and is not a cause for concern.
303a
• The use of an AC adaptor is recommended as the unit’s power consumption is relatively
high. Should you prefer to use batteries, please use the alkaline type.
304b
• Batteries should always be installed or replaced before connecting any other devices. This
way, you can prevent malfunction and/or damage to speakers or other devices.
306b
• Batteries are supplied with the unit. The life of these batteries may be limited, however,
since their primary purpose was to enable testing.
307
• Before connecting this unit to other devices, turn off the power to all units. This will help
prevent malfunctions and/or damage to speakers or other devices.
Placement
351
• Using the unit near power amplifiers (or other equipment containing large power trans-
formers) may induce hum. To alleviate the problem, change the orientation of this unit; or
move it farther away from the source of interference.
352
• This device may interfere with radio and television reception. Do not use this device in the
vicinity of such receivers.
355
• To avoid possible breakdown, do not use the unit in a wet area, such as an area exposed to
rain or other moisture.

3
IMPORTANT NOTES
Maintenance
401a
• For everyday cleaning wipe the unit with a soft, dry cloth or one that has been slightly
dampened with water. To remove stubborn dirt, use a cloth impregnated with a mild, non-
abrasive detergent. Afterwards, be sure to wipe the unit thoroughly with a soft, dry cloth.
402
• Never use benzine, thinners, alcohol or solvents of any kind, to avoid the possibility of
discoloration and/or deformation.
Additional Precautions
551
• Please be aware that the contents of memory can be irretrievably lost as a result of a
malfunction, or the improper operation of the unit. To protect yourself against the risk of
loosing important data, we recommend that you periodically save a backup copy of
important data you have stored in the unit’s memory on a paper.
552
• Unfortunately, it may be impossible to restore the contents of data that was stored in the
unit’s memory once it has been lost. Roland Corporation assumes no liability concerning
such loss of data.
553
• Use a reasonable amount of care when using the unit’s buttons, sliders, or other controls;
and when using its jacks and connectors. Rough handling can lead to malfunctions.
554
• Never strike or apply strong pressure to the display.
556
• When connecting / disconnecting all cables, grasp the connector itself—never pull on the
cable. This way you will avoid causing shorts, or damage to the cable’s internal elements.
558a
• To avoid disturbing your neighbors, try to keep the unit’s volume at reasonable levels. You
may prefer to use headphones, so you do not need to be concerned about those around you
(especially when it is late at night).
559a
• When you need to transport the unit, package it in the box (including padding) that it came
in, if possible. Otherwise, you will need to use equivalent packaging materials.

4
Installing Batteries
Insert the included batteries as shown in figure, being careful to orient the
batteries correctly.
* Make sure the “+” and “-” ends of the batteries are oriented correctly.
fig.00
When the batteries run down, the POWER indicator gets dim. If this happens,
replace with new batteries.
When replacing the batteries, use six AA type.
* Since the EQ-20’s current consumption is relatively high, we recommend the use of
alkaline batteries.
* Do not mix fresh batteries with used ones, or mix batteries of different types. Doing so
can result in fluid leakage.
* Battery life can vary depending on battery type.
Continuous usage time under battery power is about 12 hours with alkaline batteries and
about 3.5 hours with carbon batteries. (This may vary according to usage conditions.)

5
Making the Connections
Connecting to the Guitar/Bass Amplifier
* When the unit is running on battery power, the power comes on when you insert the
connector plug into the INPUT jack.
* Before connecting or disconnecting the cord, be sure to lower the volume on the amp.
* To prevent malfunction and/or damage to speakers or other devices, always turn down
the volume, and turn off the power on all devices before making any connections.
* If there are batteries in the unit while an AC adaptor is being used, normal operation will
continue should the line voltage be interrupted (power blackout or power cord disconnection).
* Once you've gotten hooked up correctly (p. 5–6), be sure to observe the following order
when switching on the power to your equipment. By turning on devices in the wrong
order, you risk causing malfunction and/or damage to speakers and other devices.
When powering up: Turn on the power to your guitar amp (or the like) last .
When powering down: Turn off the power to your guitar amp (or the like) first .
* Always make sure to have the volume level turned down before switching on power.
Even with the volume all the way down, you may still hear some sound when the
power is switched on, but this is normal, and does not indicate a malfunction.
* When operating on battery power only, the unit’s indicator will become dim when
battery power gets too low. Replace the battery as soon as possible.
Connecting to Normal Input on the Guitar/Bass Amp
fig.01
Electric
Guitar Electric Bass
or
AC Adaptor
PSA-series
(option)
Guitar Amplifier Bass Amplifier
or

6
Making the Connections
Connecting to SEND/RETURN on the Guitar Amp
The unit’s equalization effects are obtained after the preamp.
fig.02
* Match the send output level on the guitar amp and the level setting on the unit. If the
PEAK indicator lights up frequently, turn down the output on the guitar amp.
* When the guitar amp’s SEND/RETURN pedal is at +4 dBu, set the LEVEL switch on
the rear panel of the unit to +4 dBu.
Connecting to an MTR or Mixer
fig.03
Guitar Amplifier
RETURNSEND
Electric
Guitar
AC Adaptor
PSA-series
(option)
MixerMTR
Electric
Guitar Electric Bass
or
AC Adaptor
PSA-series
(option)

7
Operation
Pedal Operation
fig.04
When you switch on the power, the unit is set to the state it was in when
the power was last switched off (MANUAL/MEMORY, Memory Number).
Each press of the EFFECT ON/OFF
pedal switches effects on or off.
When effects are off, the sound
coming in through the INPUT jack is
output unchanged.
Each press of the MANUAL/
MEMORY pedal switches the
unit between “MANUAL”
and “MEMORY.”
This lights up
when set to
“MANUAL.”
This lights up
when effects
are on.
This lights up
when set to
“MEMORY.”

8
Operation
Panel Operation
When Set to “MANUAL”
fig.05
* If the PEAK indicator lights up frequently, switch the LEVEL switch on the rear panel
of the unit.
fig.06
Before you operate the LEVEL switch, be sure to turn down the volume on
all equipment to prevent malfunction or speaker damage.
When set to MANUAL, the backlit does not light up even when the
equalizer sliders, the LEVEL slider, or the EFFECT ON/OFF pedal are
operated.
LEVEL Slider
This corrects differences in
level when effects are on or off.
PEAK Indicator
Equalizer Sliders
The sliders (30, 60, 120, 200, 400, 800, 1.6 k, 3.2 k,
6.4 k, and 12.8 k [Hz]) adjust the sound quality.

9
Operation
When Set to “MEMORY”
fig.07
SELECT Button
Pressed to select a memory location (1 through 9).
Holding down the button makes the memory number
change automatically.
When the unit is shipped from the factory, equalization settings are stored
in memories 1 through 9. For information about the settings, refer to
“Factory Default Settings”(p. 17).

10
Operation
Storing Settings (Write Operation)
Even when you carry out a write operation while the MEMORY indicator is lighted
(“MEMORY”), settings made for “MANUAL” are not stored. Be sure to carry out
such operations when the MANUAL indicator is lighted (in the “MANUAL” mode).
Do not switch off the power while a write operation is in progress.
1. While at “MANUAL,”adjust the equalizer sliders and the level slider to obtain
the desired equalization.
fig.08
2. Press the LIGHT button and the SELECT button at the same time.
fig.09
The text “WRITE SURE?”flashes in the display, and the unit enters write
standby.
fig.10
* To cancel the write operation, press the MANUAL/MEMORY pedal.
Illuminated

11
Operation
3. Press the SELECT button to choose the number of the memory (1 through 9) to
store the settings.
To avoid deleting previously stored settings, check the display before
overwriting.
fig.11
4. Again press the LIGHT button and the SELECT button at the same time.
“OK”appears in the display and the write operation finishes.
fig.12
fig.13
* From step 2 and after, you cannot adjust the sound quality or volume level by moving
the sliders.
* If you want to change what is in memory, refer to “Changing What Is in Memory
Before Storing” (p. 12).
* If you want to return the settings to the factory defaults, refer to “Returning Settings
to Their Factory Defaults” (p. 16).

12
Operation
Changing What Is in Memory Before Storing
Do not switch off the power while a write operation is in progress.
1. Press the MANUAL/MEMORY pedal to change to the “MEMORY.”
fig.14
2. Press the SELECT button to choose the number of the memory you want to change.
* Holding down the SELECT button makes the memory number change automatically.
fig.15
3. Operate the equalizer sliders or the level slider to change the equalization.
The display shows the positions of the sliders stored in memory.
When you operate the sliders, the present positions (settings) flash until they
match the setup stored in memory.
Illuminated

13
Operation
fig.16
The unit enters a state where you can make changes from when the positions
of the sliders stored in memory and the present slider positions match, and the
sound quality and levels start to change.
* It only flashes once, even if you move more than one slider at the same time. Move the
sliders one at a time to make the settings.
fig.17
4. Press the LIGHT button and the SELECT button at the same time.
The text “WRITE SURE?”flashes in the display, and the unit enters write standby.
* To cancel the write operation, press the MANUAL/MEMORY pedal.
If only the SELECT button is pressed, the display changes to show the contents
of the next memory number, and the changes made in change 3 are canceled.
5. Press the SELECT button to choose the number of the memory (1 through 9) to
store the settings.
6. Again press the LIGHT button and the SELECT button at the same time.
“OK”appears in the display and the write operation finishes.
By changing the level of the setup in memory and writing it to a different memory, you
can create a booster, where the equalizer settings stay the same and the level is raised.
Flashing

14
Part Names and Functions
Front Panel
fig.18
Level Slider
This corrects differences in
level relative to whether effects
are on or off within a range of
plus or minus 15 dB.
PEAK Indicator
This lights up
when the signal
is at 6 dB before
clipping.
MANUAL
Indicator
This lights up
when set to
“MANUAL.”
MEMORY
Indicator
This lights up
when set to
“MEMORY.”
LIGHT Button
This turns the
display backlit on
and off.
SELECT Button
This changes the
memory number.
Hold down to
change rapidly.
Display
This displays the memory number (1 through 9)
and the settings in it.
This lights up when you turn on the
power or manipulate the memory
section, then goes dark about 20 seconds
after you stop operation. This is a
feature that helps save battery power. If
you want it illuminated constantly, press
the LIGHT button to make it light up.
* Please be aware that the batteries may run down
faster than normal.
Equalizer Sliders
Provide for adjustment at 30 Hz, 60 Hz,
120 Hz, 200 Hz, 400 Hz, 800 Hz, 1.6
kHz, 3.2 kHz, 6.4 kHz, and 12.8 kHz
within a range of plus or minus 15 dB.
EFFECT ON/OFF
Pedal
Each press of the
pedal switches the
effects on or off.
MANUAL/MEMORY Pedal
Each press of the pedal
switches between “MANUAL”
and “MEMORY.”
EFFECT ON/OFF
Indicator
This lights up when
effects are on.
POWER Indicator
This lights up when the
power is on. If this gets dim or
fails to light up when the unit
is running on battery power, it
means that the batteries are
depleted. Replace promptly
with fresh batteries.
“Installing Batteries”
(p.4)

15
Part Names and Functions
Rear Panel
fig.20
LEVEL Switch
This switch sets the input level to correspond to the
device connected to the INPUT jack.
GUITAR/BASS:
When using an electric guitar or bass guitar
GUITAR AMP SEND/RETURN:
When connected to send or return on a guitar
amp or the like, or when connected to a large-
volume output device
AC ADAPTOR Jack
This jack is for connecting an
AC adaptor (BOSS PSA-
series, sold separately).
Using an AC adaptor makes
possible long performances
with no worry about
batteries going dead.
INPUT Jack
This is the input jack for connecting to the output of
an electric guitar/bass or other instrument or effects
processor.
* The INPUT jack also doubles as the power switch when
the unit is running on battery power. The power comes
on when a plug is inserted into the INPUT jack, and
goes off when it is unplugged. Unplug any connected
cords when the unit is not in use.
OUTPUT Jack
This jack is for connection to
a guitar/bass amp, another
effects processor, mixer,
MTR, or the like.
“Making the Connections”(p. 5–6)

16
Returning Settings to Their Factory Defaults
You can return the settings in memories 1 through 9 to their factory defaults.
When this operation is carried out, everything that is now in memory is lost.
1. Switch off the power.
When running on battery power:
Disconnect the connection plug from the INPUT jack.
When running on power from an AC adaptor:
Disconnect the plug from the AC ADAPTOR jack.
2. While holding down the LIGHT button and the SELECT button, switch on the
power.
When running on battery power:
Insert the connection plug into the INPUT jack.
When running on power from an AC adaptor:
Insert the AC adaptor plug into the AC ADAPTOR jack.
When you release the button, “REST”appears on the display.
fig.21
* To cancel the operation, press the LIGHT button, the SELECT button, or the left or
right pedal.
3. Press the LIGHT button and the SELECT button at the same time.
“OK”appears in the display and the settings return to their factory defaults.
fig.22

17
Factory Default Settings
NUMBER 1
Guitar Clean Cutting
NUMBER 2
Mid Boost for the Lead
NUMBER 3
Slash/Metal
EQ-20 Electric Guitar Guitar Amp
CLEAN
EQ-20 OverDrive/
Distortion
Guitar Amplifier Electric Guitar
OverDrive/
Distortion
EQ-20 Guitar Amplifier Electric Guitar

18
Factory Default Settings
NUMBER 4
Acoustic
NUMBER 5
Jazz Guitar
NUMBER 6
Enhancer
NUMBER 7
For Slap Bass
NUMBER 8
For Standard Rock (for Bass)
NUMBER 9
Metal (for Bass)

19
Frequency Response
fig.23
LEVEL (dB)
+15
0
-15
30 60 120 200 400 800 1.6k 3.2k 6.4k 12.8k
FREQUENCY (Hz)

20
Sample Settings
Settings for Guitar
Booster
(connection order: EQ-20 ➔ OverDrive/Distortion)
Crunch Sound (connection order: OverDrive/Distortion ➔ EQ-20)
Pickup Simulation
(Single-coil ➔ Humbacking)
Pickup Simulation
(Humbacking ➔ Single-coil)