Ground Zero GZDSP 4.80AMP User manual

DSP-SERIES
AMPLIFIER
MANUAL
GZDSP 4.80AMP
Feature list
•4-channel amplifier with integrated 8-channel signal processor (DSP)
•High efficient 2 Ohm stable class D amplifier
•6-channel line input (RCA)
•6-channel high-level input (with auto-on function)
•AUX input (3.5 mm socket)
•TOSLINK input (sampling rate up to 24-bit/96kHz)
•Plug for optional interface (wireless music streaming)
•4-channel line output (RCA)
•8-channel signal processor (DSP) - Cirrus Logic single core 32-bit/192 kHz
•Realtime setup of DSP functions (via PC)
•Simple handling, one-page graphical user interface (Windows compatible)
•Channel separated parametric equalizer (6x 31 band / 2x 11band)
•Channel separated time alignment (0-15 ms / 0-510 cm)
•Adjustable crossover (HPF / LPF / BPF - 20 Hz to 20 kHz)
•Selectable crossover slope (6 to 48 dB/Oct)
•Selectable phase shift for each channel (0˚ or 180°)
•Memory for 10 user presets (selectable with optional remote control)
•Two optional remote-control units available (GZDSP Remote or GZDSP Touch-Remote)
to adjust main and subwoofer level, select the presets and input mode
•LED power and status indicator (protection circuit)
•Power on delay
•High temperature / short circuit / overload protection circuit)

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Package contents
•1 x GZDSP 4.80AMP amplifier
•1 x USB cable (A- to Mini-B connector) 5m
•1 x 4-channel line output harness
•1 x 6-channel high-level input harness
•1 x CD-ROM incl. PC software and driver package (for Windows)
•1 x Owner´s manual (German and English)
•1 x Fastening Kit
Optionally available:
•Remote-control unit GZDSP Remote with LED display incl. connection wire
•Remote-control unit GZDSP Touch-Remote with color LCD display incl. connection wire
•Interface GZDSP BT-Box for wireless music streaming (incl. connecting cable)
Table of content
Important safety notes and installation instructions
3
Audio connections (input)
4
Audio connections (output)
5
High-level input harness
5
PC software installation
6
Connecting the unit with a Windows PC
6
USB port selection
7
Wrong COM port error message
8
Software user interface
9
Channel selection
10
Channel matrix
11
Channel configuration (level adjustment and time alignment)
12
Application example (time alignment)
13
Adjustment of the crossover
14
Frequency chart and equalizer
15
File dropdown menu
16
Preset memory saving and loading
16
Application examples of the GZDSP 4.80AMP 17
Technical specifications
18
Error diagnosis
19
Warranty conditions
20

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Recommended wiring
GZDSP 4.80AMP
Speaker wires
min 1.5 mm² / 15 AWG
Power supply wires
min 20.0 mm² / 4 AWG
High-level input wires
min 1.00 mm² / 18 AW
Remote Leitung
min 0.50 mm² / 20 AW
Mounting instructions
•As a precaution, it is recommended to disconnect the vehicles battery before mounting (also note the vehicles manual!)
•The power supply wire (+12 V) has to be protected within max. 20 cm / 8” by a main fuse holder with matching fuse value
(Main fuse value has to be equal to the sum of values of the fuses of each connected device)
•If necessary, replace a defective fuse with the identical value only
•Never drill a hole to the vehicles gas tank or brake lines, to wirings or any other important vehicle part!
•Never pass wires over sharp edges or vehicle parts
•Keep the wiring away from the antenna and electronic devices contributing to radio reception
•Lay the power supply wiring always separated from speaker wiring
•The amplifier contains a temperature protection circuit that turns the device off in case of overheating. After a cooling time,
it will turn on again automatically. To avoid heat buildup, sufficient air supply for cooling must be provided. Never cover the
surface of the heatsink entirely.
•The amplifier should not be mounted on a heavily vibrating part or surface (e.g. subwoofer enclosure)
•If a pre-amplified output (RCA) is available (at the head unit), it is recommended to use it for input wiring
Required parts and tools for the installation
•screwdriver
•electric drill - 3 mm / 0.12“ carbide drill bit
•recommende power wiring
Selecting a mounting position
Select a suitable location that is convenient for mounting, is accessible for wiring and has an ample room for air circulation and cooling.
The unit must not be covered or mounted close to heat emitting objects. Because of the high operation temperature (up to 80°C), it is
important to ensure sufficient distance to any heat-sensitive object. Especially the distance between GZDSP 4.80AMP and any plastic part or
electronic component should be at least 3 cm (1.18”).
Mounting the Unit
You may use the unit as a template to mark the mounting holes, then remove it and drill the marked holes. Finally mount the unit with the
mounting screws.
Caution
Choose a mounting position where all electric wires are protected from being damaged by sharp edges, heat or other conditions. +12 Volt
DC electrical connections must be fused on the battery side. Make sure your head-unit and all other devices will remain turned off while
connecting parts of the system. If it is necessary to replace the fuse(s), make sure to use only an equivalent one. Using inferior fuses may
cause serious damage to your unit, wiring or even your cars electric. Any kind of damage traced back on disregard of these notes will not
be covered by the warranty!
WARNING!
High powered audio systems in a vehicle can generate "Live Concert" levels of sound pressure. Continued exposure
to excessively high-volume sound levels may cause hearing loss or damage. Also, operation of a motor vehicle while
listening to audio equipment at high volume levels may impair your ability to hear external sounds such as horns,
warning signals or emergency vehicles! This may lead to potential traffic hazards. In the interest of safety, consumer
electronics recommends listening at lower volume levels while driving.

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Audio connections (input)
1
OPTICAL INPUT
socket
(TOSLINK)
To connect a digital audio source using the optical signal (SPDIF / stereo PCM)
Attention: If the digital audio source has no level control, we strongly recommend using one of the
available remote-control units. Otherwise the audio reproduction will be applied at max level!
2
REMOTE CONTROL
socket
To connect one of the optionally available remote-control units
GZDSP Remote
or
GZDSP Touch-Remote
3
Line Input SUB
Connect the subwoofer line out of the head-unit (if available)
4
Line Input REAR
Connect the rear line output of the head-unit (if available)
5
Line Input FRONT
Connect the front line output of the head-unit (if available)
6
PC CONNECT
(MINI USB socket)
and
status indicator
To adjust the audio setting the unit must be connected to a PC using the included USB cable
(compatible Windows PC with installed DSP software from the CD). The PC can be disconnected
when the adjustment is done. The USB cable should not be extended to ensure an accurate
communication between the DSP unit and the PC. The indicator next to the MINI USB socket will
turn blue as soon as the connection has been established.
7
LINE OUT
To connect the included 4-channel RCA line out harness delivering the audio signal of channel
E/F and G/H for further amplifiers. The signal can be set using the PC software.
8
HIGH LEVEL INPUT
The High-Level Input must be used if there´s no pre-amplified output at the head-unit, nor offering
a SP/DIF signal. In this case the head-unit speaker output wires must be connected to the high-
level input harness. By using the high-level input, the DSP unit will turn on automatically
recognizing the DC level. It´s not necessary to connect the Remote-In wire to the power terminal.
Caution:
The high-level input and the line input(s) cannot be used simultaneously. This may lead
to malfunction and cause serious damage to the DSP unit.
9
AUX INPUT
The 3.5 mm socket can be connected to an additional source unit. AUX can be selected as audio
source using the PC software or one of the available remote-control units.
10
PC Link switch
To establish a wired connection to the PC, the switch must be in „USB” position. The “BT” position
is without function.
11
BT BOX socket
To connect the wireless audio interface GZDSP BT-Box or the remote-control unit
GZDSP Touch-Remote
– both are available optionally.

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Power input & speaker output connections
1
POWER INPUT
+12V
Positive terminal (battery)
GND Ground terminal
REM Remote input (in RCA mode)
or
Remote output (in high-level mode)
Never connect the remote output wire of a source unit in high-level mode to the remote terminal!
In high-level mode, the switched voltage at the terminal can be used to turn on additional
amplifiers. The current of the remote terminal is limited to
130 mA
. In case of using several units
with a common current exceeding the limitation, an additional relay is required.
2
FUSE
Defective fuses must be replaced by fuses with identical values
3
Status indicator
POWER
green/ok (regular operation mode)
PROTECT red/error (protection mode)
4
SPEAKER OUTPUT
Channel A/B/C/D speaker terminal
High-level input harness
ATTENTION!
Please note that the GZDSP 4.80AMP cannot be used in vehicles with a factory active system installed. That might lead
to serious defects of the amplifier as well as of the vehicle´s electronic system. In case of uncertainty contact your car
audio dealer or the car´s manufacturer.

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Installing the PC software
To install and use the PC software, a Windows™ XP (SP3) operating system (or later) with a USB port is required. The
installation will need about 25 MB free memory space. We recommend using a laptop for easier handling. Insert the
enclosed CD-ROM into the CD drive of your PC. If there is no CD drive available, the software can be downloaded
from the following link: www.ground-zero-audio.com
Run the setup.exe file. The installation wizard will install the software for the DSP as usual. We recommend creating a
desktop icon. The drivers will be installed automatically during the DSP software installation. The PC requires a restart
after the installation of the software
Important note for 64-bit operating systems:
It might be necessary to install the 64-bit driver manually. The driver can be found on the CD-ROM or:
www.ground-zero-audio.com
Software update:
It´s strongly recommended running always the latest DSP software. The actual version can be downloaded here:
www.ground-zero-audio.com
Connecting the DSP to the PC
Note about the USB connection:
The included USB cable should not be extended to avoid any kind of malfunction of the communication between the
DSP unit and the PC. The LED next to the USB port on the unit will light up blue as soon as the GZDSP 4.80AMP has
established a connection to the PC.

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Demo Mode (Offline Mode):
It´s possible to use the software in offline mode without having the GZDSP 4.80AMP connected to the PC to become
familiar with most of the features and to create sample setups.
USB port selection
In order to configure the DSP,
the GZDSP 4.80AMP must be connected
to a PC with the DSP software installed
using the included USB wire.
The head unit and the DSP unit must be
turned on before opening the software.
The DSP software starts by double-click
the desktop icon.
The start screen appears and
GZDSP 4.80AMP should be selected as
device (Select Device).
The latest software version can be
downloaded from this page:
www.ground-zero-audio.com
After having the DSP unit selected at the
Select Device
menu,
the
RS232 Setting
window will appear.
Usually the correct COM port will be selected automatically. The port number
may vary depending on the computer´s environment. It can be selected
manually using the dropdown menu.
Note:
The COM port will be assigned automatically by the Windows operating
system. Please note that this should be one of the ports COM1 to COM9. In
case of any problem, please follow the instructions on the next page.
A click on the
Connect
button will start the automatic connection process of
the GZDSP 4.80AMP to the PC.
Next click on
Click here to test
connects the unit to the PC.
A number of automatic tests will be initiated now and each of them marked as
OK
after successful examination.
Finally, a click on
[OK] Click here to start
will open the user interface of the
DSP software.

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Wrong COM-Port error message
If this message will appear, the operating system
assigned the wrong COM port or it was not possible
to assign one of the COM1 to COM9 ports due to
environmental issues of the PC. The COM port
assignment may be checked with the operating
system´s device manager.
In this case the correct COM port is number 3
Close the pop-up window by clicking
OK
. Now it is
possible to select the correct COM port at the Select
COM window.
Important note:
If the assigned COM port will be COM10 or even
higher one of the unused COM ports 1 to 9 has to be
deleted in order to change the previously automatically
assigned COM port for the
USB-SERIAL CH340
device.
Subsequently, the COM port can be selected in the
properties
of the
USB-SERIAL CH340
device (right click
on the device at the device manager).

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1
2
3
4
5
6
7
8
9
1
Software user interface
SOURCE
Input selection
MAIN
- RCA line
or
high-level input
AUX
- 3.5 mm input socket
SPDIF
- Optical input (TOSLINK socket)
Main volume control
Gain
- Main volume (-40dB to +12dB)
Caution:
The controls must be used carefully to avoid damaging the speakers.

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2
CH SETTING
Channel selection
Clicking the -Icon will link the relevant pair of channels allowing function
adjustments simultaneously (Crossover / Slope / Equalizer) for both channels.
Simultaneous adjustment of channel A and B
Independent adjustment of channel A and B
Clicking will copy the current adjustment of the left channel to the right channel.
Clicking will copy the current adjustment of the right channel to the left channel.
Clicking the -Icon will invert the left and right inputs.
Warning
Trying to synchronize (link) two channels, which have already been adjusted separately, will cause
a pop-up warning.
Confirming this with OK will reset all channel wise done previous adjustments. This cannot be
revoke. Therefore, either a separate adjustment is recommended or alternatively the copy-
functions or can be used.

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3
CHANNEL MATRIX
Configuration of in- and outputs
Input
– Assignment of the corresponding input channel to the respective
output A – H.
The following input options are available:
Channel A/B: F-L (Front-L) and F-R (Front-R)
Channel C/D/E/F: F-L (Front-L) and F-R (Front-R)
or R-L (Rear-L) and R-R (Rear-R)
Channel G/H: F-L (Front-L) and F-R (Front-R)
or R-L (Rear-L) and R-R (Rear-R)
or F-L+R (sum of Front-L and Front-R)
or R-L+R (sum of Rear-L and Rear-R)
or F+R-L (sum of Front-L and Rear-L)
or F+R-R (sum of Front-R and Rear-R)
SUB-L and SUB-R
SUB-L+R (sum of SUB-L and SUB-R)
Output
:
Clicking the corresponding channel will allow adjustments of crossover,
slope and equalizer functions. Same as CH Setting (2) function.
The mentioned information to channel A, B, C and D refer to the speaker
output of the GZDSP 4.80AMP. The signal of channel E, F, G and H will
be available at the RCA line output (via line out harness).
Speaker Type
: Pre-selection of the connected speakers.
3 different options can be chosen.
OFF – Channel deactivated
Fullrange – All filters deactivated! (individually selectable)
Tweeter (A/B) – Highpass filter preset 3000 Hz (12 dB/oct)
Midrange (C/D) – Bandpass filter preset 250 / 3000 Hz (12 dB/oct)
Kickwoofer (E/F) – Bandpass filter preset 80 / 250 Hz (12 dB/oct)
Subwoofer (G/H) – Bandpass filter preset 20 / 80 Hz (12 dB/oct)
Input-MIX –
Input summing of filtered signals
This setup should be chosen if the head unit has filtered (HPF/LPF/BPF) speaker output channels.
All 6 high level input channels will be summed to a full-range audio signal.
Outputs A+C+E+G receive a summed audio signal from the input channels FL+RL
Outputs B+D+F+H receive a summed audio signal from the input channels FR+RR
We recommend connecting the input channels as follows
Front left and Front right: Highpass filtered audio signal
Rear left and Rear right: Bandpass filtered audio signal

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4
5
GAIN & DELAY
SPEAKER DISTANCE
Channel configuration (level adjustments and time alignment)
Select:
Marking the channel as
Select
ed allows grouping the respective
channels together for combined adjustments of
Gain
and
Delay
.
Gain:
To adjust the output level of the respective channel
Delay(ms)
:
To adjust the time alignment of the respective channel.
Will be displayed in milliseconds.
Warning:
It is recommended to fill in the measured distances of the
speakers to the listening position first
(5)
and realize detailed
fine-tuning later at the
Delay(ms)
Phase
– 0 / 180° Phase inversion of the respective channel
– Mute of the respective channel
Speaker distance entry
Before realizing the detailed tuning of each speaker´s time
alignment
(Gain & Delay)
, the measured distances of all
connected speakers should be added to this graphic.
The exact distance between listening position (head) and the
cone center of each speaker must be measured.
The explanation of a correct implementation on the
following page can be used as an application example.

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Application example (time alignment)
All measured distances (cm) must be added to the
according fields of the graphic
Clicking the button will cause the calculation of the
respective time alignment in milliseconds and transfer
the data to the
Delay
list
Further detailed adjustments can be edited to either
the time alignment list (ms) or to the speaker distance
window (cm)
The Reset button will delete all settings of the time
alignment function. Other DSP settings remain

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6
7
SLOPE
CROSSOVER
Adjustment of the crossover
Important:
Before choosing the filter, a
Speaker Type
must be defined in window 3.
When the setup consists of a front system connected to channel A/B and
a rear speaker system connected to channel C/D, the
Fullrange
entry
should be selected. According to the speakers and listeners request a
high pass filter (HP) can be activated at the
Slope
window.
High pass (
HP
) / Bandpass (
BP
) and low pass (
LP
) can be chosen at the
Slope
window for the selected channel(s).
A slope of 6 to 48 dB/oct can be selected at the drop down menu.
Note:
The higher the selected value the steeper the slope starting at the
crossover frequency.
Adjusting the cutoff frequency
The filters can be adjusted continuously from 20 – 20000 Hz.
The controls can only be used if a filter (Slope/6) has been selected first.
Note
:
If a filter has been selected, it is possible to adjust the crossover
frequency directly with the cursor at the frequency chart (8). Click and
hold the red (HPF) or blue (LPF) dot with the cursor and move it to the
desired point on the frequency chart.
Hint:
Instead of using the crossover control, it is possible to adjust the
crossover point by typing the required value directly into the box above
and confirm with >ENTER< or by using the up/down cursor buttons.

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8
9
FREQUENCY DIAGRAM
EQUALIZER
Function of the frequency diagram
The frequency chart displays the adjustments of the 31-band equalizer (9) and the setting of the
crossover (7) for every output channel or a pair of output channels.
Furthermore, the curves can be adjusted individually using the mouse (drag&drop).
Adjusting the parametric 31-band equalizer
The output channels A to F can be equalized by adjusting 31 frequency bands (20 - 20000 Hz) using
the controls (-18 to +12dB) individually. The subwoofer output channels G/H offer 11 bands (20 - 200
Hz) to adjust the audio signal.
Each frequency can be adjusted individually in 1-Hz steps in the F(Hz) window.
Additionally, it is possible to change the filter Q (bandwidth/slope) by typing the required value directly
into the box below each band control (0,5/narrow - 9,0/wide) or by using the up/down cursor buttons.
Furthermore, the curves can be adjusted individually in window 8 using the mouse (drag&drop).
The EQ-function can be deactivated with the button without resetting the EQ-setup.
Using the button will cause a full reset of the EQ-setup to factory setting. (Other adjustments are
not affected).

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FILE dropdown menu
*Important: The 10 presets can be used if the optional remote control GZDSP Remote or GZDSP Touch-Remote is
connected. Without the remote-control unit, it is only possible to use and edit the last preset that has been saved.
Preset memory saving and loading
*Note: All presets must be covered in numerical order (Pos 1>Pos 2>Pos 3>…) without skipping a position, otherwise
it will not be possible to access all presets with the remote control.
PC Contrl
Opens the „Select COM“ window (page 9)
Open
Opens a setup file that has been saved previously to the PC memory
or an external drive
Save
Saves the current setup as a file to the PC with unmodified filename. If
no filename has been selected yet, the dialogue will ask for the input.
Save as
Saves a setup file with a certain filename.
Factory setting
Sets the unit to default settings
Class-D AMP Setting
No function
Write to Device*
Saves the current setting to the preset memory of the GZDSP 4.80AMP
unit. At the following window, the preset number can be selected.
Read from Device*
Opens one of the available presets from the memory of the
GZDSP 4.80AMP. The preset can be selected from the following
window. The blue frame indicates the actually selected preset number.
Exit
Closes the DSP software
Open the dropdown menu at
Select Save Place
and choose one of the
preset positions. Confirm by clicking
Save
Open the dropdown menu at
Select Read Place
and choose one of the
preset positions. Confirm by clicking
Read

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Application examples
GZDSP 4.80AMP offers various system configurations. Here is a description of the two most common applications:
Front and rear speaker system
+ subwoofer (e.g. active sub)
2-way front system (active) +
+ subwoofer (e.g. active sub)
Channel
A/B
Front system at speaker output
High pass filter
HP: 50 – 80 Hz
Tweeter at speaker output
High pass filter
HP: 2500 – 4500 Hz
C/D
Rear system at speaker output
High pass filter
HP: 50 – 120 Hz
Midwoofer at speaker output
Bandpass filter
HP: 50 – 80 Hz
LP: 2500 – 4500 Hz
E /F
-
-
G/H
Subwoofer
Bandpass filter
HP: 10 – 30 Hz
LP: 50 – 80 Hz
Subwoofer
Bandpass filter
HP: 10 – 30 Hz
LP: 50 – 80 Hz
Note: The final crossover points depend on the speaker’s capacity that have been installed. The technical specifications
of the speakers will supply more information about possible applications and suggested crossover points.
Above, these are just noncommittal examples. Ground Zero will not be legally responsible for any kind of damage of
speakers or other components caused by wrong settings.

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Technical Specifications
Model
GZDSP 4.80AMP
Type
4-channel amplifier with integrated signal processor (DSP)
Frequency range
20 Hz – 20 KHz
(-3 dB)
RMS Power @ 4 Ω
CEA Standard CEA-2006-A
4 x 80 W (1% THD+N)
RMS Power @ 2
Ω
CEA Standard CEA-2006-A
4 x 130 W (1% THD+N)
Processor
Cirrus Logic single core 32 bit, 8-channel, 192 kHz
Sensitivity
High level input: 2 – 15 V RMS
AUX input: 0.6 – 5 V RMS
Input resitsance
>47 kΩ (low level input)
Output
4-channel speaker output
4-channel line output (RCA)
Input
6-channel high level input
AUX (3.5 mm socket)
Digital input: TOSLINK optical max. 24bit/96 kHz (PCM stereo)
Remote out
max. 130mA
Recommended fuse
2 x 30 A
Dimensions
Heatsink only
W x H x L
185 x 39 x 181 mm
7.28“ x 1.54“x 7.13“
Dimensions
Whole unit
W x H x L
185 x 42 x 215 mm
7.28“ x 1.77“x 8.46“
Software compatibility
Microsoft Windows™ XP SP3, Vista, 7, 8, 8.1,10
Preset
10 x individually adjustable / selectable using the optionally available
remote control unit GZDSP Remote or GZDSP Touch-Remote
Gain range
-40 to +12dB
Equalizer
6 x 31 bands at output A - F (20 – 20000Hz), -18 bis +12dB, Q 0.5 - 9
2 x 11 bands at output G&H (20 – 200Hz), -18 bis +12dB, Q 0.5 - 9
Tiome alignment
0 – 15 ms / 0 – 502 cm per channel
Crossover
6 / 12 / 18 / 24 / 30 / 36 / 42 / 48 dB/oct (BPF / LPF / HPF Butterworth)
20 – 20000 Hz
Phase shift
0° / 180° per channel
Optionally available
Remote control units
GZDSP Remote
or
GZDSP Touch-Remote
(main level, subwoofer level, source selection and preset selection)

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Error diagnosis
Error
Control
Help / Solution
No function PWR LED on?
check the fuse(s)
check the remote wire (not required in high-level mode)
check the auto-on switch position (in high-level mode)
check the +12 Volt connection and wire
check the ground connection and wire
No sound
(PWR LED on)
no setup selected
select the setup using the DSP software
signal wire no contact or broken
check the contact or replace the wire
no audio signal from the head-unit
check the audio output signal of the head-unit
non-operational further amplifier
check the remote wire connection (if used)
check the further amplifier´s power supply
non-operational source is selected
check the source unit
MUTE function activated (software)
check the setup using the DSP software
level at optional remote control is too low
check the setting at the remote control
Single channels
with no function
signal wire has no contact or it´s broken
check the contacts or replace the wire
no audio signal from the head-unit
check the audio output signal of the head-unit
balance or fader control of the head-unit is
not in the center position
check the setting of the head-unit
wrong setup of input and output mode
check the setup using the DSP software
gain (level) is too low, or the MUTE function
is activated in the DSP setup
check the setup using the DSP software
Impure sound,
incorrect stereo
reproduction
inverted phase of one (or more) speakers
check the polarity of the speaker connection
check the polarity of the high-level input
check the PHASE setting
check the TIME ALIGNMENT adjustment
Distorted sound
quality
speaker overload
reduce the volume level
check the high-pass filter and the slope of the filter
DSP input override (distortion)
select the correct input mode
pay attention to the input sensitivity of the unit
head-unit output override (distortion)
reduce the volume level of the head-unit
set the sound controls of the head-unit to center position
-deactivate the LOUDNESS function of the head-unit
amplifier override (clipping)
max output power of the GZDSP 4.80AMP exceeded.
reduce the level to avoid damaging the amplifier or the speakers
Increased
noise level
gain (level) is too high
reduce the gain (level) using the DSP software
head-unit creates noise(s)
select a superior quality head-unit
use the optical output (if available)
let the audio store or manufacturer check the head-unit
Car specific
interferences
audible
diverse power supplies or ground connection
the head-unit, GZDSP 4.80AMP and each further amplifier
should be wired up to a common ground, as well as a common
+12 Volt terminal
signal wire has no contact or it´s broken
check the contacts or replace the wire
defective head-unit
let the audio store or manufacturer check the head-unit
defective amplifier
let the audio store or manufacturer check the amplifier
this or further amplifier(s) mounted near
automotive control units
choose a mounting position far away from automotive units
OEM head-unit´s analog output connected
(although car supports MOST connection)
use the MOST audio signal of the OEM head-unit*
*Note:
To use the digital MOST audio signal of the OEM head-unit as source, an optional MOST to SP/DIF signal converter is
requested. Connect the SP/DIF signal directly to the digital input of the GZDSP 4.80AMP using TOSLINK connectors.

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Terms of warranty
The limited warranty for this product is covered by Ground Zero´s local distribution partners and their
terms and conditions. For further information contact your local retailer or distributor.
Ground Zero GmbH
Erlenweg 25, 85658 Egmating, Germany
Tel. [phone] Fax -8310
www.ground-zero-audio.com