GR BASS DUAL Series User manual

USERS MANUAL
DUAL

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USER MANUAL PURPOSE
This user manual is dedicated to the use of the bass am-
plifiers DUAL.
The manual includes the following information:
• General information (technical data and packaging);
• Description of the amplifier’s functions.
All the informations described on this user manual are
verified.
The manufacturer reserves the right to update or modify
their product without any notice.

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PACKAGING AND STORAGE
PACKAGING
MINI ONE is packed in a special cardboard box. The box
contains the amplifier, power supply cable and the user
manual.
TRASPORT
Please handle the box with care. A specific position du-
ring the transport is not required.
STORAGE
Please keep the amplifier in a dry and ventilated place.
Ideal storage conditions: temperature within -20C and
40C, Humidity 20% to 80%.
PRODUCT DISPOSAL
Please follow the disposal instruction issued by your lo-
cal council.
In accordance with European Directive 2002/96 / EC, all
electrical and electronic products should be disposed
by specific collection facilities appointed by the go-
vernment or the local authorities.
DECLARATION OF CONFORMITY
The product complies with the following European di-
rective:
2014/35 / EU - Electrical Safety
2014/30 / EU - Electromagnetic Compatibility
2011/65 / EU - Limited use of certain hazardous substan-
ces in electrical and electronic equipment
A full copy of the declaration of conformity is available
from the manufacturer.
The manufacturer is not responsible of any damage due
to an improper use of the product.

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DESCRIPTION
The GR-DUAL bass head offers the best compromise
between portability and versatility for the modern bass
player. This powerful amp holds two separate channels
(each with dedicated functionality), giving the possibility
to setup your rig in many different ways.
Ch1 and Ch2: Gain, 4 Band EQ, Deep Boost, Bright Bo-
ost, Line Out, DI and Master Volume.
extra on Ch1: Tuner, Pure Sound (by-pass of all EQ fun-
ctionality), Send/Return and Headphones.
extra on Ch2: Drive with low cut, drive modes and blend
function..
Main possible setups are:
A: Use the two different EQ settings with the same in-
strument (connected to Ch1 INPUT).
Using the CHANNEL SELECTOR on MIX it is possible to
mix the two settings into the same output or change
between the two (also possible by using the separately
sold pedal board).
B: Two different instruments (such as a bass and a dou-
ble bass or a keyboard) on two independent channels.
The dedicated DI OUT for each channel is an important
feature of our GR-DUAL:
• Ch1 and Ch2 DI can run separately, one for each indivi-
dual channel.
• Both channels could be mixed into one DI (out on Ch1).
Being able to manage two different sounds at once could
make huge difference in both live and studio situations.

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MAIN FEATURES
• 2 SPEAKON audio outputs (DUAL 1400: 1400W), 2 SPEA-
KON audio output (DUAL 800: 800W)
• XLR DI Independent out (Ch1, Ch2)
• DI volume (Ch1, Ch2)
• Anti-bump on DI out
• Pre/post Eq. DI (Ch1, Ch2)
• Ground Lift DI (Ch1, Ch2)
• Headphones Output
• Tuner Output
• Send-Return (Ch1)
• Aux-In
• Output 9V, 250 mA
• Output USB charger, 300mA
• Gain control (Ch1, Ch2)
• Channel selector
• Bass, Mid-Low, Mid-High and High equalization control
(Ch1, Ch2)
• Mid-Low frequencies switch (Ch1, Ch2)
• Mid-High frequencies switch (Ch1, Ch2)
• Deep boost (Ch1, Ch2)
• Bright boost (Ch1, Ch2)
• Pure Sound setting (Ch1)
• Mute
• Headphones volume
• Master Volume control
• VU-Meter
• Chromatic tuner
• “Studio” and “Live” fan mode operation
• OVERDRIVE
• Drive Low Cut filter
• Drive
• Blend
• Drive mod.

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TECHNICAL FEATURES DUAL 1400
• POWER RMS 1400W @ 4Ω
• DYNAMIC RANGE: 117dBA
• Parameters of nominal distortion output: a) TDH+N: -
0.005 % @ 1 W (4Ω, 1 kHz), 0.0008 % @ 50 W (4Ω, 100 Hz)
• Low output impedance: 6mW
• Total Efficiency: 84 % @ 1400W, 4Ω
TECHNICAL FEATURES DUAL 800
• POWER RMS 800W @ 4Ω
• DYNAMIC RANGE: 117dBA
• Parameters of nominal distortion output: a) TDH+N: -
0.005 % @ 1 W (4Ω, 1 kHz), 0.0008 % @ 50 W (4Ω, 100 Hz)
• Low output impedance: 6mW
• Total Efficiency: 84 % @ 800W, 4Ω

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a >
1 2 3 4 5 6
b >
8 10 11 1213
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15
16
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19 20
21 22 23 24
18 9
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CONTROLS DESCRIPTION
FRONT PANEL CONTROLS
1.a INPUT JACK Ch1
1.b INPUT JACK Ch2
Input jack for you bass. We suggest to use a good quality
cable, in order to obtain the best audio performance.
2. AUX-IN
3.5mm jack Auxiliar input to connect an external audio
device
3.a GAIN CONTROL KNOB Ch1
3.b GAIN CONTROL KNOB Ch2
Sets the input signal amount of the pre-amp
4.a BASS KNOB Ch1
4.b BASS KNOB Ch2
Increases or reduces the bass frequencies of the signal
5.a MID-Low KNOB Ch1
5.b MID-Low KNOB Ch2
Increases or reduces the mid-low frequencies of the
signal

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6.a MID-High KNOB Ch1
6.b MID-High KNOB Ch2
Increases or reduces mid-high frequencies of the signal
7.a HIGH KNOB Ch1
7.b HIGH KNOB Ch2
Increases or reduces the high frequencies of the signal
8.a DEEP BUTTON Ch1
8.b DEEP BUTTON Ch2
Gives a more deep sound
9.a BRIGHT BUTTON Ch1
9.b BRIGHT BUTTON Ch2
Gives a more bright sound
10.a MID-Low SWITCH Ch1
10.b MID-Low SWITCH Ch2
Use this switch to change the frequency of the mid-low
band from 185 Hz, 375 Hz and 800 Hz.
11.a MID-High SWITCH Ch1
11.b MID-High SWITCH Ch2
Use this switch to change the frequency of the mid-high
and from 600 Hz, 1200 Hz and 1800 Hz.
12. PURE SWITCH
Allows to bypass all the equalization filters of the pream-
plifier.
The pure-mode activation is signaled by the orange LED
on the top of the button.
13.a DI KNOB Ch1
13.b DI KNOB Ch2
Controls the DI volume
14. HEADPHONES KNOB
Controls the headphones volume
15. HEADPHONES OUTPUT
3.5mm plug for headphones
16.a MASTER KNOB (CH1)
Controls the overall volume of the channel 1 output
16.b MASTER KNOB CH2
Controls the overall volume of the channel 2 output
17. OPERATION LED
Green = normal operation.
Orange = high level of the input signal (clip).

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18. VU-METER - Chromatic tuner
24 LEDs bar that can be used as VU-METER, in order to 8
visualize the signal intensity, or as Chromatic tuner.
The six central LEDs, labeled by the letters B E A D G C,
are very important when the LEDs bar is used as chroma-
tic tuner. In fact they identify six different musical notes.
Each of these LEDs will light blue or red, depending on
whether you are playing a tuned or untuned note. In the
case of an untuned note, the red LEDs on the left or the
red LEDs on the right of the six central one, will red light
up indicating a waning or increasing note respectively.
The higher is the number of red LEDs on the more impor-
tant is the untuned condition.
19. LED BUTTON
By pressing this button you can: a-scroll through the four
VU-Meter display modes, b-select the mode tuner, c- turn
off the 24 LED bar.
The last selection made on this button is always memori-
zed.
On the DUAL 800 and DUAL 700x2 amplifiers, pressing
the LED button for about 8 seconds allows to select the
operation mode of the fans by switching from “LIVE” to
“STUDIO” and vice-versa; a brief flash of 24 LEDs visually
displays the selection change.
In “LIVE” mode the fans will activate when the amplifier
reaches a safe temperature threshold. In “STUDIO” mode,
the fans are normally turned off; however, after several
hours of use and under rather hard climatic conditions,
the fans may turn on. Every time the amplifier is switched
on, the operating mode is reset to “LIVE” mode.
20. MUTE BUTTON
Turn off the amplifier output. The activation of this mode
turns on the red LED on the left of the button. In this
mode the Tuner is always on, whatever LED-mode is on.
21. CutLOW
Cuts low-end frequencies(High-pass filter) before the
OVERDRIVE stage to make more clear and intelligible
distorted sound
22. DRIVE KNOB
Increases or reduces the amount of distortion.
23. BLEND KNOB
Select the clean/distorted ratio of the signal.

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24. DISTORTION MOD BUTTON
Select the type of distortion (soft/hard clipping).
REAR PANEL CONTROLS
AC POWER SOCKET (230V - 115V)
IEC plug for power supply connection . The power supply
self-recognation feature allows to power the GR-ONE with
a voltage of 230V or 115V. The supplied cable is equipped
with a ground wire. For safety and security reasons, never
unplug the ground wire from your equipments.
POWER ON/OFF SWITCH
Switch on and off the amplifier.
9 VDC Out
9V DC output to connect external equipment (we recom-
mend to connect 4-5 pedal effect maximum). The polarity
is center negative.
USB CHARGER Out
5V DC USB output to charge your phone or any USB devi-
ce. It delivers up to 300mA of current.
SEND
6.35mm jack plug to connect an external effect’s input

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RETURN
6.35mm jack plug to connect an external effect’s output
DI OUTPUT (Ch1, Ch2)
XLR plug.
The DI output is equipped with anti-bump, which allows
you to turn on and off GR-ONE even with the mixer line
still on, without causing the annoying and noisy bump.
GND LIFT BUTTON (Ch1, Ch2)
Isolates the DI output from the ground wire.
PRE-POST DI BUTTON (Ch1, Ch2)
Allows you to choose the type of signal to be sent to the
DI output DI: PRE EQ or POST EQ.
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SPEAKON OUTPUT
It is possible to use a 6.35 mm jack. We recommend to
use a 2 poles speakon connector. Never use a 6.35 jack
guitar cable to connect your amplifier to your speakers.

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LIMITED WARRANTY
The warranty covers a period of five years.
The warranty covers any defects in material or wor-
kmanship under normal use during the warranty period.
Any shipping cost to/from the repair service centre is the
customer’s responsibility.
In the event of an irreparable damage or repeated failure
of the same type, the manufacturer may replace the unit,
within the term of the original warranty.
The warranty does not cover parts which may result faulty
due to:
- Negligence or careless use
- Improper installation and maintenance
- Tampering made by unauthorized personnel
- Damages that might not be related to manufacturing
defects.
The manufacturer accepts no responsibility for any dama-
ge due to persons, animals or things, as consequence of
the failure to comply all the installation requirements and
/or use indicated in this user manual.

via Conchia 54T 70043 Monopoli (Ba)
tel.: [phone]
[email protected]om > www.grbass.com