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MPC-X100 100 Hz Subwoofer Crossover
For JBL MPC and MPA amplifiers
Owner’s Manual and Installation Guide
I. Description
The MPC-X100 is a dual-channel 100 Hz crossover filter accessory for use with JBL MPC
and MPA power amplifiers.
The MPC-X100 is user configurable to fulfill these functions:
active crossoverChannel 1: 100 Hz low-pass; Channel 2: 100 Hz high-pass or full-range.
subsonic filterprogrammable; preset @ 20 Hz to protect against damage from infrasonic signals.
ultrasonic filte
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II. Installation CAUTION: The MPC-X100 contains active components which can be damaged by electro- static discharge (ESD). Be sure to practice standard ESD precautions, and always ground yourself and your workstation before handling exposed circuit cards. Installing the MPC-X100 requires PC board soldering skills. Only qualified service technicians should attempt it. Any authorized JBL service center can perform the installation. The MPC-X100 installs on the amplifier input board of any JBL MPA
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NOISE SHIELD NOISE SHIELD #4-40 NUT TAB CH. 1 GAIN CONTROL INPUT PANEL PCB Figure 3 Figure 4 8 If you need to make any adjustments to the MPC-X100 settings or if you need to record them, do so now, because the MPC-X100 will be inaccessible once the noise shield is installed and the input panel is re-installed into the amplifier chassis. See Section III, Programming the MPC-X100, below. 9 Using a ¼-inch (6.3 mm) nutdriver, remove the outer 4-40 nut from the stud in the panel mounting bracket, n
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Bridged Mode OperationWith the amplifier in bridged mono mode and driving a high- power subwoofer system, the MPC-X100 can be used as a subwoofer filter, taking full-range audio from Channel 1s input and sending on a 100 Hz low-pass signal to the amplifier circuitry. For correct operation, bypass Channel 2 on the MPC-X100 board and use only Channel 1s input and processing. Bypassing the filters To completely bypass the filter circuitry of a channel, set the jumpers on both Jx01 and Jx02 acros
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Inserting the resistor networkThe factory preset frequency is 20 kHz. If there is a resistor network already installed in the socket, carefully pull it straight out. Insert the pins of the new resistor network into the socket holes and carefully press the network into the socket. Be careful to avoid bending the pins of the resistor network. Orientation of the resistor network is unimportant, as long as all 8 pins are well seated in the socket. CD Horn Equalization (Boost)In addition to enablin
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Ultrasonic Filter Applications: An ultrasonic filter is useful for minimizing RF interference, oscillations, leakage or aliasing from digital devices, or other signals that are too high in pitch to hear but may wreak havoc in an amplifier system. Typical ultrasonic filters are set at 16 kHz or 20 kHz. Program settings: 1 Set J201 to enable the low-pass filter by placing jumper across pins 2 and 3. 2 No jumper on J203 unless you need CD horn equalization. 3 Insert proper resistor network in RN202
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Channel 2: 3 Set J202 to enable the Channel 2s 100 Hz high-pass filter by placing jumper across pins 2 and 3. 4 CD horn EQIf you need equalization for a constant-directivity horn, set a jumper on J203 for the amount of boost you need. If you do not want CD horn equalization, do not place any jumper on J203. 5 Ultrasonic filteringIf you need ultrasonic filtering, set a jumper on J201 across pins 2 and 3 to enable Channel 2s Low-pass filter and insert a resistor network into RN202 that corresp
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Appendix Identifying resistor networks Use this chart to identify the values of the resistor networks. See the tables on page 4 to find the correct values for the desired filter frequencies. RESISTANCE CODE 2.7K 272 3.9K 392 4.7K 472 5.6K 562 6.8K 682 Use only these three digits to 8.2K 822 determine resistance code. 10K 103 Disregard the other 12K 123 numerals and letters. 15K 153 18K 183 20K 203 22K 223 27K 273 33K 333 39K 393 47K 473 56K 563 68K 683 JBL Professional 8500 Balboa Boulevard, P
