GT-50 5-Channel, High-Current/High-Power Amplifier Table of Contents Parts List Features and Specifications Control Functions Control functions (cont.) Control functions (cont.) 3 3 4 5 6 Mechanical Functions Control cover removal and reinstallation Multi-position mounting feet Mechanical functions (cont.) Vents Amplifier linking Wire connection Fuses 6 6 6 7 7 7 7 7 General Installation Precautions Before you install Battery and charging system Wire routing 8 8 8 8 Installation--Amplifier Mounting Choose the mounting location Installation--amplifier mounting (cont.) Passenger and trunk compartment mounting 9 9 10 10 Installation--Fuses and Wiring Amplifier fuses Wire gauge Installation--fuses and wiring (cont.) Power/B+ and power/ground connection Remote input connection Speaker output connection Installation--fuses and wiring (cont.) Mono subwoofer operation 10 10 10 11 11 11 11 12 12 Setup Tuning--Full-Range Speakers Music Front, rear, and subwoofer sensitivity controls Front, rear, and subwoofer crossover controls Setup tuning--full-range speakers (cont.) Head unit Volume Front and rear input sensitivity control Front and rear crossover controls Setup tuning--full-range speakers (cont.) Front and rear Q-factor adjustments Rear input sensitivity and crossover controls 12 12 12 12 13 13 13 13 13 14 14 14 Setup Tuning--Subwoofers Subwoofer level control Subwoofer mode switch Setup tuning--subwoofers (cont.) Head unit Volume Subwoofer sensitivity control Subwoofer crossover control Phase 14 14 14 15 15 15 15 15 15 System Examples Amplifier Troubleshooting Guide Contact and Warranty Information 2 16,17 18 19 Parts List Included Hardware (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 Features and Specifications GT-50 Features 5-Channel, High-Current Amplifier 2 Mono Operation Advanced Cooling Allows Varied Mounting Positions Adjustable Feet for Varied Mounting Surfaces Security Cover Protects Control Settings Power Increase with Input Voltage Rise Continuously Variable Crossovers and Q-factor Settings Selectable Highpass Front and Rear Channels Discrete Subwoofer Channel Inputs Selectable 24dB or 12dB Subwoofer Lowpass Setting Optional Remote Subwoofer Level Control Enhanced Switching Assignments GT-50 Specifications 14.4VDC Power Multi-Channel Power @ 4 Multi-Channel Power @ 2 Mixed Op. Power @ 4, 2 12.6VDC power Multi-Channel Power @ 4 Multi-Channel Power @ 2 Mixed Op. Power @ 4, 2 Frequency Response (-3dB) Signal-to-Noise Ratio (A Weighted) Dimensions 4x55W, 1x250W 4x85W, 1x350W 4x55W, 1x400W 4x45W, 1x190W 4x65W, 1x250W 4x45W, 1x300 10Hz­95kHz >100dB 21/4x215/8x8 7/8" (57 x 548 x 225mm) 3 Control Functions 4 OFF H I G H PA S S ON STEREO 7 MONO L+R REAR INPUT OFF 4 ON H I G H PAS S STEREO 10 FRO NT + REAR M O NO L OFF 11 ON S U B WO O F E R L E V E L 9 N O N P R I N TA B L E A R E A L OW PA S S O F F 1 2 d B 24dB FUSE 3 x 30A 350 200 Hz 350 200 Hz 350 200 Hz 20 0.2 IN P U T S E N S ITIV I T Y 20 1.2 0.95 Q/HP INPUT SENSITIVITY 50 1.2 0.95 Q/HP INP UT SENSITIVITY L R L R B+ B+ G ND G ND 0.2 2.6 V 0.2 2.6 V 2.6 V 5 R E M OT E 0.7 R E M OT E 5 0.7 RE M OTE SUBWO O FER LEVEL 5 FRO NT S P E AKE R O UTPUT REAR SPEAKER OUTPUT S U B WO O F E R O U T P U T P OW E R P OW E R 3 5 3 5 3 STATUS F RO N T SPEA K ER O U T PU T R EA R SPEA K ER O U T PU T SU B WO O F ER O U T PU T B+ POWER POWER B+ GND GND L ON SAFE R L R 1 2 12 6 2 8 2 11 1 FRONT RCA Inputs RCA cables marked "FRONT" from head unit or from other line level device should be connected here. Use both inputs (L & R) for stereo. 1 2 2 FRONT, REAR, and SUBWOOFER Remote Inputs 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. The remote inputs are all in parallel. Only one is to be used. Use any one of the three remote inputs to turn the amplifier on. Do not connect external 12-volt accessories to these inputs. 3 FRONT, REAR, and SUBWOOFER Input Sensitivity Controls Turn control clockwise to increase the amplifier sensitivity to incoming signals. Turn control counterclockwise to decrease the amplifier sensitivity. 4 FRONT and REAR Highpass Crossover Controls To use 12dB/octave crossover, move 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.) OFF HIGHPASS ON 350 200 Hz 20 4 Control Functions (cont.) 5 FRONT and REAR "Q" Controls "Q" Control is active when the highpass crossover is engaged and is centered on the selected crossover point. The range of operation is 0.7­1.2. dB Q +1.6dB 0dB -3dB .707 .95 1.2 t (tuned crossover frequency) 7 6 8 2 6 REAR RCA Inputs RCA cables marked "REAR" from head unit or other line level device should be connected here. Use both inputs (L & R) for stereo. 7 REAR Input Switch In the left (STEREO L-R) position, the L & R inputs go to the REAR L & R channels of the amplifier. In the right (FRONT L-R) position, the inputs are derived from the FRONT channels and sent to the REAR L & R channels of the amplifier. STEREO REAR INPUT FRON T 8 SUBWOOFER RCA Inputs RCA cables marked "subwoofer" from head unit or other line level device should be connected here. Use both inputs (L & R) for dual subwoofer output from head unit. Use left (L) input only when single subwoofer output is to be connected. 7 8 8 2 9 Lowpass Slope and Crossover Controls Select appropriate crossover slope of 12 or 24dB/octave by moving LOWPASS SLOPE switch. Lowpass crossover frequencies are adjustable from 50Hz to 350Hz by rotary control. O FF ON LOWPASS OFF 12dB 24dB SUBWOOFER LEVEL 350 200 Hz 50 10 SUBWOOFER Mode Switch Move switch to left position (MONO L-R) when used with L & R subwoofer RCA outputs. Move switch to middle position (L-MONO) when used with single subwoofer RCA outputs. Move switch to right position (NON-FADING MONO) when subwoofer signal is to be derived from front and rear channels. MONO L M ONO NON-FADI NG M ONO 5 Control Functions (cont.) 11 Subwoofer Level Control and Port Switch should be set to "OFF" when control circuit is not installed, (see optional "subwoofer level control" owner's manual). cover panel 12 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." Mechanical Functions Recessed RCA Inputs The input jacks are recessed into the body of the amplifier to provide clearance in tight mounting locations. 1 inch 1 inch 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. 6 Mechanical Functions (cont.) 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 Amplifier Linking The design of the side panels enables multiple amplifiers to be used together without additional hardware. GT-50 GT-20 Wire Connection Amplifier accepts stripped wire directly into the terminal blocks. Speaker outputs accept 8-gauge, and the DC power and ground accept 4-gauge. Tighten with supplied hex wrenches. Fuses Amplifier accepts standard AT-style automotive blade fuses. FUSE 3 x 30A 7 General Installation Precautions 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 attempted. 8 Installation--Amplifier Mounting 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! WARNING! Before driving the mounting screws through any surface, be sure of what is behind that surface. Check for gas tank, brake lines, and any vehicle wiring harness. 13mm (1/2") 225mm (87/8") N O N P R I N TA B L E A R E A OFF HIGHPASS ON STEREO REAR INPUT MONO L+R HIGHPASS OFF ON STEREO MONO L F RONT + REAR SUBWOOFER LEVEL OFF 1 2 d B 2 4 dB OFF ON LOW PAS S FUS E 3 x 3 0 A 350 200 Hz 350 200 Hz 350 200 Hz 20 0.2 INPUT SENSITIVITY 20 1.2 0.95 Q/HP INPUT SENSIT IVIT Y 50 1.2 0.95 Q/HP INPUT S E NS ITIV ITY L R L R B+ B+ G ND G ND 0.2 2.6 V 0.2 2.6 V 2.6 V 5 REMOTE 0.7 REMOT E 5 0.7 REMOT E SUBWOOFER LEVEL 5 FRONT SPEAKER OUTPUT RE AR S P E AKE R O UTP UT SUBWOOFER OUTPUT POWER POWER GT-50 STATUS F RO N T SPEA K ER O U T PU T R EA R SPEA K ER O U T PU T SUBWOOFER OUTPUT B+ P OW E R P OW E R B+ GND GND L ON SAFE R L R 57mm (21/4") 548mm (215/8") 9 Installation--Amplifier Mounting (cont.) Passenger and Trunk Compartment Mounting If the amplifier is mounted under a seat, be sure that the vents do not become blocked. Do not allow seat padding or other obstructive material to press down on the amplifier. All Boston GT amplifiers have top panel controls. If the amplifier is mounted under a seat, position the amplifier so the cover panel can be removed with the seat forward or back to allow adjustment of the audio settings. 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, doublestick tape, or by wedging into position. Amplifier should be mounted using the movable mounting feet and the provided mounting screws. Installation--Fuses and Wiring Amplifier Fuses Although the amplifier has internal fuses, additional fusing should be provided at 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 fuses of the amplifier if only the 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. FUSE 3 x 30A Wire Gauge The amplifier accepts up to 4-gauge stripped wire at the DC power and ground input terminals, and 4-gauge is recommended. Wire runs should be kept to the minimum practical length. 10 Installation--Fuses and Wiring (cont.) Power/B+ and Power/GND Connection Strip approximately 5/8" (16mm) of insulation. The positive (+) power wire is installed into the amplifier terminal marked "B+." 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 B+ and GND terminals with the supplied 3mm hex wrench to secure the wire into the terminals. If the power wire must be routed through a drilled or e ...