Ground Zero GZRA 4HD User manual

RADIOACTIVE SERIES
4-CHANNEL
AMPLIFIER
GZRA 4HD
Owner´s Manual
Features
•High-performance class D amplifier
•2 ohms stable in stereo mode
•4 ohms stable in bridged mode
•High-level input with auto-on feature
•Adjustable wide band active crossover
•Adjustable input sensitivity
•Turn-on delay
•Thermal protection circuit

GROUND ZERO GZRA 4HD
RADIOACTIVE SERIES

GROUND ZERO GZRA 4HD
RADIOACTIVE SERIES
Mounting instructions
•As a precaution, it is recommended to disconnect the vehicles battery before mounting the amplifier.
Note: For new vehicles, disconnecting the battery might cause various errors in your vehicle´s electric
system that can be cleared only by authorized service partners of your vehicle´s manufacturer! Please
ask your service partner first before disconnecting the battery!
•The power supply wire (+12 V) has to be protected within max. 20 cm / 8” by a main fuse holder with
a fuse value matching the recommendation for your amplifier
Note: If there is more than one amplifier connected using this power wire, the main fuse value must be
equal to the sum of the recommended fuses of all connected devices. However, make sure the
diameter of your power wire will be enough for the required current!
•If necessary, replace a defective fuse by a fuse with identical quality and value
•Never drill holes to the vehicle´s gas tank, brake lines, to wirings or any other important vehicle parts!
•Never pass wires over sharp edges or vehicle parts due avoid any kind of damage
•Keep the wiring away from the antenna and electronic devices contributing to radio reception
•Lay the power supply wiring always separated from speaker wiring to avoid disturbance
•The amplifier contains a temperature protection circuit that turns the device off in case of overheating.
After a certain cooling time, it will turn on automatically. To avoid heat build-up, enough air supply for
cooling must be provided. Never cover the surface of the amplifier´s heatsink entirely
•The amplifier should NEVER be mounted onto a vibrating part or surface such as a subwoofer
enclosure. This might lead to malfunction due to loosened electrical parts inside the amplifier.
•Some amplifiers offer a high-level input option, however if a pre-amplified output (RCA) is available (at
the head unit), it is strongly recommended to make use of them.
Terms of warranty
The limited warranty for this product is covered by GROUND ZERO´s regional distribution partners and their
terms and conditions. For further information contact your local retailer or distributor.
Recommended wiring
Speaker wires
min 2.5 mm² / 13 AWG
Power supply wires
min 20 mm² / 4 AWG
GROUND ZERO products are engineered in Germany
GROUND ZERO – international sponsor

GROUND ZERO GZRA 4HD
RADIOACTIVE SERIES
Controls & Features
1
Power terminal
+12V To be connected to the positive terminal of the battery
REM To be connected to the remote output of the head unit*
(*not required in high-level input mode)
GND To be connected to the vehicle´s ground
(or directly to the negative terminal of the battery)
2
Fuse(s)
If necessary to replace a defective fuse, it´s strongly recommended to
use a fuse with identical value
3
Speaker terminal
To connect the speaker wires / min. 2 ohms stereo or 1 ohm bridged
4
Input mode switch
(RCA)
To select between 4 channel or only 2 channel input mode according
to the quantity of RCA wires available from the head unit
5
Line input (RCA)
Input sockets to connect RCA wires
Important note: High-level and RCA inputs should
never
be used
simultaneously! This may cause serious damage to the amplifier
6
High-level input
Head units without RCA pre-amplifier output signal can be connected
using the high-level input to connect the speaker output of the head
unit directly.
If used, the amplifier turns on automatically (auto-on feature)
The remote input of the power supply terminal remains unused
Important note: High-level and RCA inputs should
never
be used
simultaneously! This may cause serious damage to the amplifier
7
Sensitivity control
Controller to adjust the input sensitivity (CH 1/2 & CH 3/4)
8
Low pass filter
To adjust the required crossover point. Frequencies above the selected
crossover point will be filtered (40 Hz to 4000 Hz) (CH 1/2 & CH 3/4)
9
High pass filter
To adjust the required crossover point. Frequencies below the selected
crossover point will be filtered (40 Hz to 4000 Hz) (CH 1/2 & CH 3/4)
10
Status indication
POWER (green) ok (correct operation)
PROTECT (red) error (protection mode)

GROUND ZERO GZRA 4HD
RADIOACTIVE SERIES
4-channel mode RCA input wiring
4-channel mode high-level input wiring

GROUND ZERO GZRA 4HD
RADIOACTIVE SERIES
4-channel mode speaker wiring
2-channel mode (bridged) wiring

GROUND ZERO GZRA 4HD
RADIOACTIVE SERIES
Specifications
Model
GZRA 4HD
Amplifier type
4 channel class D
RMS Power @ 4 Ω
CEA Standard CEA-2006-A
4x 175 W (1% THD+N)
RMS Power @ 2 Ω
CEA Standard CEA-2006-A
4x 275 W (1% THD+N)
RMS Power @ 4
Ω
in bridged mode
CEA Standard CEA-2006-A
2x 550 W (1% THD+N)
2x 700 W (10% THD+N)
Low pass filter
40 Hz – 4000 Hz (12 dB/oct)
High pass filter
40 Hz – 4000 Hz (12 dB/oct)
Frequency response
10 Hz – 25 kHz
Signal to noise ratio (SNR)
-102.3 dB
Total harmonic distortion (THD+N)
< 0.1%
Damping factor
> 200
Input sensitivity
200 mV – 5.3 V
Fuse(s)
3x 35 A
Recommended main fuse
100 A
Dimensions
w x h x l (heatsink / overall)
186 x 52 x 229/268 mm
Dimensions
w x h x l (heatsink / overall)
7.32 x 2.05 x 9.02/10.55“
Trouble shooting guide
Symptoms
Check / Cause
Action
No audible sound Does the POW LED turn to green?
Check protection fuse(s) of the amplifier (harness)
Check remote wire connection (RCA input mode)
Check +12 Volt power supply wire connection
Check ground wire connection
Did the PROTECT LED turned to red?
Check for speaker short or amplifier overheating
Device does not
turn on
Power supply of the amplifier?
Check power wire or connections
Remote wire powered? (RCA input
mode)
Check remote wire connection to the head unit
No sound on one
channel
Speaker wiring undamaged?
Check for short circuit or open connections
Input signal on each RCA lead?
Reverse left and right RCA inputs to check the
audio input signal
Device turns off at
medium / high
volume
Load impedance of each speaker
correct?
Check if each speaker load impedance matches
the technical specifications of the amplifier
Status LED turned
on red
Temperature protection circuit active
Decrease head unit’s volume / wait for cooling
Speaker wires short / speaker
damaged
Check speaker / wires and insulate if necessary

GROUND ZERO GZRA 4HD
RADIOACTIVE SERIES
Listening to music can be emotional, impressive, relaxing or enjoyable. At that, it doesn´t really
matter what kind of music is the personal favorite, whether it´s Instrumental, Jazz, Electro,
Latin, Classic, Rock or any other music direction. However, audio reproduction quality at each
desired volume is elementary. Some music styles require higher levels while others prefer the
soft tones.
GROUND ZERO considers all the different wishes of customers during the development of
new products. Along with this, the target is to create the most realistic sound, to transfer the
soul of the music and the intention of the performer. Summarized to one phrase: RESPECT THE
MUSIC!
Ground Zero GmbH
Erlenweg 25, 85658 Egmating, Germany
Tel. [phone] Fax -8310
www.ground-zero-audio.com