Boston Acoustics GT-28, GT-24 User Manual
GT-28
2-Channel, High-Current/High-Power Amplifiers
GT-24
2
Table of Contents
Parts List 3
Features and Specifications 3
Control Functions 4
Control functions (cont.) 5
Mechanical Functions 6
Recessed RCA inputs 6
Control cover removal and reinstallation 6
Multi-position mounting feet 6
Vents (side and rear) 6
Mechanical functions (cont.) 7
Amplifier linking 7
Wire connection 7
Fuses 7
General Installation Precautions 8
Before you install 8
Battery and charging system 8
Wire routing 8
Installation—Amplifier Mounting 9
Choose the mounting location 9
Height, width, and depth diagrams 9
Installation—amplifier mounting (cont.) 10
Passenger & trunk compartment mounting 10
Installation—Fuses and Wiring 10
Amplifier fuses 10
Wire gauge 10
Installation—fuses and wiring (cont.) 11
Power/B+ and power/ground (GND) connection 11
Remote input connection 11
Speaker output connection 11
Installation—fuses and wiring (cont.) 12
Mono subwoofer operation 12
Setup Tuning—Full-Range Speakers 12
Music 12
Sensitivity controls 12
Highpass and lowpass crossover controls 12
Setup tuning—full-range speakers (cont.) 13
Head unit 13
Volume 13
Input sensitivity control 13
Crossover controls 13
Setup tuning—full-range speakers (cont.) 14
“Q” control 14
Setup Tuning—Rear Fill Speakers 14
Setup Tuning—Subwoofers 14
Input switch 14
Setup tuning—subwoofers (cont.) 15
Head unit 15
Volume 15
Input sensitivity control 15
Lowpass crossover control 15
Phase 15
System Examples 16,17
Amplifier Troubleshooting Guide 18
Contact and Warranty Information 19
Included Hardware: GT-28 & GT-24
(1) owner’s manual
(1) female quick-connect terminal for remote input
(1) 2mm hex wrench (for speaker input)
(1) 3mm hex wrench (for power input)
(6) mounting screws
3
Parts List
Te chnical Specifications
GT-28 GT-24
14.4VDC Power
@ 4 Ohms 2x250W 2x175W
@ 2 Ohms 2x450W 2x275W
@ 4 Ohms (mono) 1x900W 1x550W
@ 2 Ohms (mono) 1x1350W 1x900W
12.6VDC Power
@ 4 Ohms 2x200W 2x120W
@ 2 Ohms 2x350W 2x200W
@ 4 Ohms (mono) 1x700W 1x440W
@ 2 Ohms (mono) 1x1100W 1x750W
Frequency Response (-3dB) 10Hz–95kHz 10Hz–95kHz
Signal-to-Noise Ratio (A Weighted) >100dB >100dB
Dimensions (HxWxD) 21/
4x21
5
/
8x8
7
/
8” (57x548x225mm) 2
1
/
4x18x8
7
/
8” (57x458x225mm)
GT-28 and GT-24 Features
2-Channel, High-Current Amplifier
2Ω Mono Operation
Power Increase with Input Voltage Rise
Advanced Cooling Allows Varied Mounting Positions
Adjustable Feet for Varied Mounting Surfaces
24dB or 12dB Octave Lowpass Setting
Continuously Variable Crossover and Q-factor Settings
Selectable Highpass, Lowpass, and Bandpass Settings
Bandpass Configurable for Midbass or Subwoofer
Te rminals Accept Bare, Heavy-Gauge Wire
Screw-Down Security Cover Protects Tuning Controls
Optional Remote Subwoofer Level Control
Features and Specifications
4
Control Functions
RCA Inputs
RCA cables from head unit or from other line level device should be connected
here. Use both inputs (L and R) for stereo; use “L” input for mono.
Remote Input
Use the supplied FEMALE quick-connector to connect the REMOTE trigger lead
from the head unit to the amplifier. Amplifier turns “ON” when head unit is turned
“ON.” One FEMALE .210" connector is supplied with amplifier.
Input Switch
In the left position, the L and R inputs go to the L and R channels of the amplifier. In the right position, the input is for mono operation.
Input Sensitivity Control
Tu rn control clockwise to increase the amplifier sensitivity to incoming signals. Turn
control counterclockwise to decrease the amplifier sensitivity.
Highpass Crossover Controls
To use 12dB/octave crossover, move HIGHPASS switch to right-hand position.
Highpass crossover frequency is adjustable from 20Hz to 350Hz by rotary control.
(Moving switch to left-hand position will bypass crossover functions.)
1
2
1
2
3
4
5
4
8
6
7
5
3
2
1
GT-28 Top Panel Shown
GT-28 Front Panel Shown
9
10
9
MONO
STEREO
OFF
INPUT
SUBWOOFER LEVEL
L
INPUT SUBWOOFER LEVEL
REMOTE
ON
LOWPASS SLOPE
12dB
ST
INPUT SENSITIVITY 2.6
OFF
LOWPASS
12dB
24dB
MONO
200
ON
OFF ON
HIGHPASS
350
350
185
Hz
Hz
50
20
0.2
1.2
0.95
Q/HP
5
0.7
MONO
L
SPEAKER OUTPUT
R
B+ B+
12.6–14.4VDC
FUSE 4 x 25A
GND
GROUND
GND
STATUS
ON
SAFE
MONO
L R
12.6–14.4VDC
B+ B+
GROUND
GND
STEREO
GND
MONO
INPUT
L
INPUT SENSITIVITY 2.6
OFF ON
HIGHPASS
185
0.2
5
350
Hz
20
Lowpass Crossover Controls
To use lowpass crossover move LOWPASS switch to righthand position. Lowpass
crossover frequency is adjustable from 50Hz to 350Hz by rotary control. (Moving
switch to left-hand position will bypass crossover functions.)
Lowpass Slope
Select appropriate crossover slope of 12 or 24dB/octave by moving LOWPASS
SLOPE switch.
“Q” Control
The “Q” Control is active when the highpass crossover is engaged and is centered on the selected crossover point. The range of operation is 0.7–1.2.
Subwoofer Level Control Port
SUBWOOFER LEVEL switch should be set to “OFF” when control circuit is not
installed, (see optional Subwoofer Level Control owners manual).
Status LED Indicators
GREEN indicates the normal operating condition; the amplifier is “ON.” GREEN
and RED together are normal when the amplifier is first turned “ON”; RED will
turn off after a few seconds. When both GREEN and RED remain on, the amplifier is in thermal shutdown condition. RED only indicates a fault condition, “SAFE.”
5
Control Functions (cont.)
6
7
8
9
LOWPASS SLOPE
12dB
24dB
MONO
12dB
ST
10
+1.6dB
0dB
-3dB
dB
Q
OFF
200
ON
LOWPASS
350
Hz
50
1.2.95.707
(tuned crossover frequency)
t
6
Mechanical Functions
Recessed RCA Inputs
The input jacks are recessed into the body of the amplifier to provide clearance in tight mounting locations.
Control Cover Removal and Reinstallation
The cover panel is secured with two (2) captive coin-slotted screws. Coin-slotted screws allow a coin edge to be used as a screwdriver to remove the panel.
Multi-Position Mounting Feet
The mounting feet are designed to slide in both directions to clear installation obstructions on the mounting surface.
WARNING! Before driving the 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.
Vents (Side and Rear)
The cooling vents must be kept clear of obstructions once the amplifier is
installed. Failure to do this could lead to premature thermal shutdown or amplifier failure.
upper side vent
lower side vent
1 inch 1 inch
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