User manual JBL GTS50

[. . . ] Installation and Use Refer to the "Crossover Frequency Adjustments" and "Speaker Level Input Impedance Adjustments" sections of this manual to see if you will need to make alterations to their factory settings. If you are not using the built-in crossover, or the speaker level inputs, you may skip this step. Note: If the vehicle's radio features a code type security system, make certain you know the code before disconnecting the battery!Run a minimum AWG #8 power cable complete with a 40 amp fuse (not included) for the GTS300 or an AWG #6 or AWG #4 cable with an 80 amp fuse for the GTS50 directly from the positive + 12V battery terminal to the disired amplifier location. [. . . ] See the "Adjusting the Gain" section for tips on proper setup. Preamp-Output Crossover Switch ­ This switch controls the built-in crossover that is directed to the preamp-output connectors. Set this switch to "Low-Pass" to activate the lowpass filter on the preamp output (for subwoofer use). Set the switch to "High-Pass" to activate the high-pass filter for use with satellite speakers. Speaker Output Crossover Switch ­ This switch controls the built-in crossover that is connected to the power amplifier circuitry. Set this switch to "Low Pass" to activate the low pass filter on the amplifier (for subwoofer use). Set the switch to "High Pass" to activate the high pass filter for use with satellite speakers. Input Mode Selector ­ This switch is used to set the input mode for both preamp and speaker-level inputs. Set this switch to Stereo for normal operation using both left and right inputs. Set this switch to R to drive both the left and right output channels with only a single input on the right channel. Set this switch to "L+R" to sum the left and right inputs for a mono output on both amplifier channels. On some older, or lowerpriced head units, this load will not facilitate proper fader operation. To provide for this, we have provided the ability to change the input impedance of the speakerlevel inputs to 15 ohms. This is accomplished by connecting the jumpers as shown in the diagram below. JUMPER SELECTOR SELECT 100K OR 15 OHMS Crossover Frequency Adjustments The GTS300 and GTS50 amplifiers include built-in frequency selectable crossovers. One crossover is connected in series with the amplifier circuitry and the other crossover is connected to the preamp level output jacks. These crossovers can be set in either the "flat" (full bandwidth operation), Low Pass (Subwoofer operation), or High Pass (satellite operation). · The crossover frequencies are set by "chips" inside the amplifier. These "chips" are simply a set of resistors, connected across the pins and molded into a single package. The crossover frequencies may be changed to any value desired by changing the resistor network. JBL has "chips" available in the popular values listed in the table below. If none of these suit your system, you may pruchase compatible resistor networks from a local electronics store, or you may build you own custom values from discrete resistors mounted on a 14-pin "DIP Header" using the instructions which follow. · If the head unit has 4 channels of builtin amplification and/or an electronic fader control, you should leave the jumpers in the factory set position. · If the head unit has 2 channels of amplification, with a speakerlevel fader, the jumpers should be set to the 15-ohm position. [. . . ] · Incorrectly connected or shorted speaker wires; check for shorts in wiring. · Defective or disconnected audio cables; check for continuity and replace if necessary. · Incorrect Gain Adjustment; verify that the amplifier gain controls are not turned completely down. If they are, sound output level may be very low and may give the impression that the system) or part of the system) is dead. Power light is on, but no sound is heard from some or all of the speakers · Defective head unit or signal processor; check each component for proper wiring and operation. 12 · Defective GTS300 or GTS50; If there is audio signal present at the input of the amplifier and there is no output, the GTS300 or GTS50 may be defective. [. . . ]