User manual BOSTON ACOUSTICS GT50

[. . . ] 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 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. [. . . ] 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. When using two (2) subwoofers, each subwoofer should be a minimum 4-ohm [or higher] impedance, (see System B, page 17). Subwoofer impedance must not fall below 2 ohms when in MONO mode. SU B WO O FER O U TPU T Setup Tuning--Full-Range 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) FRONT, REAR, and SUBWOOFER Sensitivity Controls Turn controls all the way counterclockwise (minimum position). In this position, the amplifier will be less sensitive to the input signal from the head unit. 3) FRONT, REAR, and SUBWOOFER Crossover Controls Crossovers should be turned off during this phase of set-up. Move the HIGHPASS and FILTER switches to the "OFF" position--with these settings, full-range signal is sent to the FRONT & REAR speaker outputs. OFF OFF HIGHPASS ON ON L OW PA SS O F F 12d B 24d B SU B WO OF ER L EVEL 350 200 Hz 350 200 Hz 20 50 FRONT and REAR crossover controls 12 SUBWOOFER crossover control Setup Tuning--Full-Range Speakers (cont. ) 4) Head Unit The head unit should have all controls such as bass, treble, balance, and fader set to the flat or centered position. 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 GREEN status LED is lit 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. ) WARNING!A distorted signal from the head unit sent to the amplifier can cause loudspeaker failure at higher listening levels! 6) FRONT and REAR Input Sensitivity Controls Slowly rotate control clockwise until maximum undistorted playing level is heard from the speakers. If detected, rotate FRONT Input Sensitivity counterclockwise until it is eliminated. 7) FRONT and REAR Crossover Controls To achieve higher undistorted playing levels from the front speakers, the FRONT crossover must be engaged. Slowly rotate FRONT input sensitivity control clockwise until maximum undistorted playing level is heard from the speakers. If detected, rotate FRONT input sensitivity control counterclockwise until it is eliminated. Slowly rotate FRONT 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 FRONT input sensitivity control counterclockwise until it is eliminated and/or rotate the FRONT highpass crossover control clockwise to raise the crossover point. OFF H I G H PA S S ON 350 200 Hz 20 13 Setup Tuning--Full-Range Speakers (cont. ) 8) FRONT and REAR "Q" Controls Once the FRONT highpass crossover point has been determined, use the FRONT "Q" control to increase the bass information centered around the crossover point. Setting the front "Q" control is done in conjunction with setting the levels on the input sensitivity and highpass crossover frequency controls. You may find while setting the "Q" that bottoming may be detected in the front speakers; lowering the "Q" input sensitivity or raising the highpass crossover point will eliminate this. [. . . ] Your responsibilities are to use the system according to the instructions supplied, to provide safe and secure transportation to an authorized Boston Acoustics service representative, and to present proof of purchase in the form of your sales slip when requesting service. Excluded from this warranty is damage that results from abuse, misuse, accidents, shipping, or repairs or modifications by anyone other than an authorized Boston Acoustics service representative. This warranty is void if the serial number has been removed or defaced. This warranty gives you specific legal rights, and you may also have other rights that vary from state to state. If Service Seems Necessary First, contact the dealer from whom you purchased the amplifier. [. . . ]