GTA
High Performance
5 Channel Amplifier
Introduction
Thank you for choosing Boston Acoustics and congratulations, you’ve made the right choice. You’re now equipped for the open road. Your high performance GTA amplifiers are engineered to perform and built to last.
These products represent the pinnacle of performance and innovation that
Boston Acoustics is famous for. We hope you enjoy your amplifier and the road ahead.
Technical Specifications:
Front & Rear Channels
Rated Power (CEA-2006-A):
@ 4-Ohm (Stereo):
@ 2-Ohm (Stereo):
@ 4-Ohm (Mono):
@ 2-Ohm (Mono):
Impedance Stability:
Frequency Response (-3dB):
Signal-to-Noise Ratio:
(A Weighted)
THD+N:
Highpass Crossover:
Frequency Range:
Slope (dB Per Octave):
Lowpass Crossover:
Frequency Range:
Slope (dB Per Octave):
Signal Voltage Input Range:
Low Level (RCA) Input:
Speaker Level Input:
Fuse Amp Rating (ATC):
Dimensions:
Width:
Height:
Depth:
70 Watts x 4
125 Watts x 4
250 Watts x 2
N/A
2 Ω St / 4Ω Mono
10Hz–50kHz
>90dB
1%
50Hz - 200Hz
12dB
50Hz - 200Hz
12dB
200mv - 5v
400mv - 10v
3 x 25 Amp
21 1 ⁄
4
” (538mm)
2 3 ⁄
8
” (60mm)
8 3 ⁄
8
” (211mm)
Subwoofer Channel
N/A
N/A
250 Watts x 1
400 Watts x 1
2 Ω
10Hz–150Hz
>90dB
1%
10Hz - 50Hz
12dB
50Hz - 150Hz
12dB
Parts List:
Owners Manual:
2mm Hex Wrench:
3mm Hex Wrench:
4mm Hex Wrench:
Speaker Level Input Cable:
Mounting Screws:
Replacement Fuses (ATC):
2 x 1 x 1 x 1 x 1 x 1 x 4 x 3 (25 amp)
Connections and Controls
1 2 3 4 5 1 2 3 4 5 2 1 4 6 7 8 9 10 11 12 13 14 u RCA Input (Left and Right)Speaker Level Input v Speaker Level Input w Crosssover Filter Switch (HP / Off / LP) x Gain (250mv to 5.0v - continuously variable) y Crossover Frequency Adjustment (50Hz to 200Hz - continuously variable) z Q-Tune
™ “Q” Adjustment (0.707 to 1.6 - cont. variable)
{ Lowpass Crossover Adjustment (50Hz to 150Hz - cont. variable))
| Q-Tune
™ Highpass (Subsonic) Adjustment (10Hz to 50Hz - cont. variable)
} GTA-RSL Port (Remote Gain)
~ Speaker Output Block (Front and Rear Speakers)
Speaker Output Block (Subwoofer)
13 14 15
Power Block (12v / Remote / Ground)
13 14 15
Status LED
The Boston Logo will illuminate “Blue” under normal operating conditions.
The LED will illuminate “Red” during start-up and under fault conditions. If the
LED is still red after start-up, please refer to troubleshooting on page 10.
Speaker Level Input Cable
GTA amplifiers offer a dedicated speaker level input for ease installation into factory systems when an RCA (low level) signal is not available. Wiring code for the cable is industry standard;
White Solid = Left Positive White w/ Black Stripe = Left Negative
Gray Solid = Right Positive Gray w/ Black Stripe = Right Negative
Warning: Do not connect both Speaker Level and RCAs into the amplifier at the same time as damage to the amplifier may occur.
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Installation - General
WARNING! Before driving the amplifier mounting screws through any surface, be sure of what is behind that surface. Check for the gas tank, brake lines, and any vehicle wiring harness. Never run wires outside or under the vehicle or where they could become broken or interfere with the safe operation of the vehicle.
Before You Install
Before you install the unit, disconnect the negative (–) battery cable in the engine compartment of the vehicle. Doing so will prevent damage to both the electrical system of the vehicle and the amplifier during installation.
Battery and Charging System
In order for the amplifier to function correctly, the electrical system of the vehicle should be professionally checked for overall electrical capacity. When used, the amplifier will increase the demand on the battery and alternator.
Therefore, both should be thoroughly evaluated before installing the amplifier to ensure they are in normal operating condition and able to handle the increased demand the amplifier will present to the vehicle’s electrical system.
Wire Routing
Do not run the power wire near any low-level signals or audio cables such as the RCAs from the head unit. Noise can be introduced into the amplifier when this occurs. It is helpful to diagram the wire layout first before any installation is initiated.
Choose the Mounting Location
Plan your installation so that the amplifier is mounted where adequate ventilation is available. Never mount an amplifier in the engine compartment of a vehicle!
Passenger and Trunk Compartment Mounting
If the amplifier is mounted under a seat, be sure that there is adequate space around the amplifier once installed, 1” (25mm) recommended minimum. Do not allow seat padding or other obstructive material to press down on the amplifier.
When mounting in a trunk, choose a location that will be protected from sliding cargo or other materials. Mount the amplifier to solid surfaces only. Do not mount to plastic trim panels. Do not mount the amplifier with Velcro, double-stick tape, or by wedging into position. Amplifier should be mounted using the screw mounts in the endpanels and with the provided mounting screws.
Cooling
Position the amplifier so that there is adequate space around the amplifier once installed, 1” (25mm) recommended minimum.
4
Installation - Wiring
Amplifier Fuses
Although the amplifier has internal fuses, additional fuse protection should be installed as close as possible to the battery on the positive (+) power wire going to the amplifier. An inline fuse should be installed at no more than 18" (46cm) on the positive (+) power wire. The rating of the inline fuse should equal the value of the internal fuse of the amplifier if only the single amplifier is connected to this wire. If other devices are connected to this wire, the fuse value should be of sufficient capacity to handle the demand.
Wire Gauge
The amplifier accepts up to 4-gauge stripped wire at the DC power and ground input terminals, and 4-gauge is recommended as a minimum. Wire runs should be kept to the minimum practical length.
Power 12v and Ground (GND) Connection
Strip approximately 5/8” (16mm) of insulation. The positive (+) power wire is installed into the amplifier terminal marked “12v”. The negative (–) wire is installed into the terminal marked “GND”. The ground wire should be as short as possible and connected directly to the chassis of the vehicle. Make sure that the chassis connection point is free of rust, grease, dirt, paint, and other materials that may insulate the ground wire from making proper connection.
Tighten the 12v and GND terminals with the supplied 4mm hex wrench to secure the wire into the terminals. If the power wire must be routed through a drilled or existing hole, use a nylon panel grommet to prevent the insulation from fraying. Failure to do so could lead to an electrical short if the wire insulation is worn through and the power wire is shorted to ground.
Remote Input Connection
Connect the REMOTE trigger lead from the head unit to the amplifier using the
3mm hex wrench to tighten the connector on the power block of the amplifier.
(refer to the diagram on page 3).
Speaker Output Connection
Prepare each wire by stripping approximately 5 ⁄
8
” (16mm) of insulation. The positive (+) speaker wires are installed into the amplifier terminal marked “SPEAK-
ER OUTPUT” / “+” (refer to the diagram on page 3). The negative (–) speaker wires are installed into the amplifier terminal marked “SPEAKER OUTPUT” /
“-”. Tighten the “SPEAKER OUTPUT”, “+”, and “-” terminals with the supplied
2mm and 3mm hex wrenches to secure the wires into the terminals. If the speaker wires must be routed through a drilled or existing hole, use a nylon panel grommet to prevent fraying the wire insulation. Failure to do so could lead to an electrical short if the wire insulation is worn through and the speaker wires are shorted to ground.
WARNING! Front and Rear Speakers impedance must not fall below 2-ohms
Stereo / 4-ohms Mono. Subwoofer impedance must not fall below 2-ohms.
5
Tuning The Amplifier - Front And Rear Speakers
1) Music
The material chosen for head unit/amplifier system setup must be both clear in recording quality and dynamic in amplitude. Many audiophile “test” discs have musical tracks with both of these characteristics and should be used.
2) Input Sensitivity Control (Gain)
Turn control all the way counterclockwise (minimum position). In this position, the amplifier will be less sensitive to the input signal from the head unit (refer to the diagram on page 3).
3) Crossover Control
Crossovers should be turned “OFF” during this phase of setup . Move the X-OVER switch to the “OFF” position (refer to the diagram on page 3), with these settings, full-range signal is sent to the speaker outputs. If over-excursion is detected from speakers, move the switch to “HP” and slowly rotate clockwise until over-excursion is eliminated.
4) Head Unit
The head unit should have all controls such as bass, treble, balance, and fader set to the flat or centered position. The volume control should be at the minimum setting.
If the head unit has any equalization or bass management features such as boost, they should be defeated at this time. Turn head unit on, and verify that the BLUE status LED is illuminated on the amplifier.
5) Volume
With the chosen musical track playing, turn the head unit volume control up until the maximum level of undistorted signal is heard from the speakers. (For most head units, this will be near the end of the volume control range.)
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Configuration and Connection Diagram:
Front & Rear Speakers - 80Hz Highpass
Subwoofer - 80Hz Lowpass, 35Hz Highpass, and Q of 1.2
Tuning The Amplifier - Front And Rear Speakers
WARNING! A distorted signal from the head unit sent to the amplifier can cause loudspeaker failure at higher listening levels.
6) Input Sensitivity Control (Gain)
Slowly rotate the control clockwise (refer to the diagram on page 3) until maximum undistorted playing level is heard from the speakers. Listen closely for bottoming from the speakers. If detected, rotate the input sensitivity control counterclockwise until it is eliminated.
7) Crossover Controls
To achieve higher undistorted playing levels from the front or rear speakers, the
Highpass crossover must be engaged. Rotate the crossover control fully clockwise
(refer to the diagram on page 3). The highpass crossover point is now set at
200Hz. Q-Tune should be set to off.
Slowly rotate the input sensitivity control clockwise until maximum undistorted playing level is heard from the speakers. Listen closely for bottoming from the speakers. If detected, rotate the input sensitivity control counterclockwise until it is eliminated. Slowly rotate the highpass crossover control counterclockwise while listening for bottoming. You are lowering the crossover point, which means that more bass signal is being sent to the speakers. If bottoming is detected, rotate the input sensitivity control counterclockwise until it is eliminated and/or rotate the
Highpass crossover control clockwise to raise the crossover point.
Connection Diagram: akers - 80Hz Highpass s 35Hz Highpass, and Q of 1.2
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Tuning The Amplifier - Subwoofer(s)
1) Head Unit
The head unit should have all controls such as bass, treble, balance, and fader set to the flat or centered position. The volume control should be at the minimum setting. If the head unit has any equalization or bass management features such as boost, they should be deactivated at this time. Turn head unit on, and verify that the Blue status LED (logo) is illuminated on the amplifier.
2) Volume
With the chosen musical track playing, turn the head unit volume control up until the maximum level of undistorted signal is heard from the speakers. For most head units, this will be at the end of the volume control range.
WARNING! A distorted signal from the head unit sent to the amplifier can cause speaker failure at higher listening levels.
3) Input Sensitivity Control (Gain)
Turn control (refer to the diagram on page 3) all the way counterclockwise
(minimum position). In this position, the amplifier will be less sensitive to the input signal from the head unit. Slowly rotate this control clockwise until maximum undistorted playing level is heard from the subwoofer(s). Listen closely for faults such as bottoming from the subwoofer(s). If fault is detected, rotate input sensitivity control counterclockwise until fault is eliminated. At this point, the maximum undistorted subwoofer playing level has been defined.
8
Configuration and Connection Diagram:
Front & Rear Speakers - 80Hz Highpass
Subwoofer - 80Hz Lowpass, 35Hz Highpass, and Q of 1.2
Tuning The Amplifier - Subwoofer(s)
4) Lowpass Crossover Control
Experiment with the crossover point settings while the subwoofer is active.
A higher setting will increase the perceived output, and a lower setting will make the bass response more omnidirectional. Since the Lowpass cannot be disengaged, set to 15Hz if using an outboard processor or electronic crossover on the headunit.
5) Q-Tune ™ Control
Once the highpass crossover point has been determined, use the Q-Tune™ control
(refer to the diagram on page 3) to increase the bass information centered around the highpass crossover point.
Setting the Q-Tune™ control is done in conjunction with setting the levels on the input sensitivity and highpass crossover (subsonic) frequency controls. You may find while setting the Q-Tune™ that over-excursion may be detected in the subwoofer (s); lowering the Q-Tune™ input sensitivity or raising the highpass crossover point will eliminate this. Minor adjustments to each setting are required to fine-tune the system.
Setting the Q-Tune™ is a subtle process. It is recommended that the Q-Tune™ setting be left in the 0.7 position and adjusted only after the input sensitivity and highpass crossover ranges are known. Small adjustments to the Q-Tune™ setting are all that are required to fine-tune the system.
6) GTA-RSL Subwoofer Output Control
The optional remote level control (GTA-RSL) gives you independent level adjustment of the subwoofer’s output level beyond the standard system volume control. Please refer to the GTA-RSL’s manual for installation instruction. The GTA-RSL is available separately, please consult your authorized Boston Acoustics dealer.
Connection Diagram: akers - 80Hz Highpass s 35Hz Highpass, and Q of 1.2
9
Amplifier Troubleshooting Guide
Status LEDs on Amplifier not Lit—Head Unit (Source) Turned “ON”
Verify Remote turn-on wire from source to amplifier has proper voltage
Power (B+) connections at amplifier, terminal blocks, and battery are secure
Ground (GND) connections at amplifier and vehicle chassis are secure
Battery B+ fuse and amplifier fuse are OK
B+ at battery and B+ at amplifier have proper voltage
Status LEDs Lit, no Output from Speakers—Speakers in Normal Operating Condition
Verify High-level cables from speaker(s) to amplifier are securely connected
RCA or Speaker Level Input from amplifier to source are securely connected
Sensitivity adjustment on amplifier is correctly adjusted
Engine Noise from Speaker(s)
Turn source “OFF” and disconnect RCA cables at amplifier
If noise stops, check equipment and cables leading to amplifier
Verify RCA cables are of good quality with no breakage to internal shields
RCA cables from source to amplifier are not run alongside power
Amplifier Output Distorted—Music not Recorded with Intentional Distortion
Verify Source output to amplifier is not distorted
Amplifier input sensitivity is correctly adjusted
Amplifier Shutting Down, RED LED Lit—Amplifier in Thermal Protection Mode
Verify Amplifier is mounted with adequate space around heatsink
Amplifier is not mounted under carpet
Speakers meet correct impedance for application (mono or stereo hookup)
Amplifier not Turning “ON”, RED LED Lit—Amplifier not Connected to a Shorted Speaker
Verify Speaker crossover is not defective
High-level cables from speaker to amplifier are not shorted
Amplifier not Turning “ON”, RED LED Lit—Speakers, Crossovers, and Cable OK
Internal fuse needs to be replaced
Verify Replace fuse with fuse of same value
Amplifier not Turning “ON”, RED LED Lit—Speakers, Crossovers, and Cable OK
Amplifier requires service
If Service Seems Necessary:
First, contact the dealer from whom you purchased the product, or contact us via email at:
USA and Canada: [email protected]
Europe: [email protected]
Japan: [email protected]
Asia/Pacific countries: [email protected]
We will promptly advise you of what action to take.
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Boston Acoustics, Inc. 300 Jubilee Drive, Peabody, MA 01960 USA
T: 978.538.5000 F: 978.538.5100 W: bostonacoustics.com/car
Boston, B/A ellipse symbol, Boston Acoustics, and the Boston Acoustics logo are registered trademarks and Q-Tune is a trademark of Boston Acoustics, Inc.
Specifications are subject to change without notice. © 2010 Boston Acoustics, Inc. All rights reserved. Covered by patents issued and/or pending. 142-003890-0
