JBL GTH400-20107 manual Custom Chip Construction, Resistor 500,000 Value Frequency in Hz Ohms

GTH400-20107 06/03/98 15:49 Side 13

Custom Chip Construction

Regardless of whether you build or buy it, the necessary resistor network has the following configuration:

•Each resistor in the package has the same value.

•If you know the crossover frequency you want, you can calculate the resistor value necessary by solving the following equation:

Resistor			2,500,000
Value	=
		Frequency in Hz
in ohms

•Use the following equation if you have a resistor pack of a known value, and want to find its crossover frequency:

Frequency	=	2,500,000
in Hz		Resistor Value
		in ohms

•To build chips from discrete resistors, solder the resistors to a standard 14- pin “DIP Header” according to the diagram. If a DIP Header is not available, you may bend the leads of

1⁄4 -watt resistors 90 degrees, trim them to 1⁄8"-length, and insert them directly into the chip sockets.

To change the crossover frequency change the resistor network as follows:

1.Remove the screws from the bottom panel as shown below.

2.Select which resistor module, high pass or low pass, that you wish to change.

3.A chip puller, which can be obtained from any electronics store, is recommended to remove the resistor chip. Pull the resistor chip from the socket as shown in the figure below.

.	CA
NORTHRIDGE,PC00108800
JBL INC	GTS600	A
JBL	REV

4.Place the new module in the socket making sure all pins are lined up with the socket holes. Press the module firmly into the socket.

5.Replace the bottom lid.

For further information on how to use the speaker output and preamp output crossovers for system building see the “Typical Applications” and “Add-On and Upgrade Steps” sections.

Remote Chassis Installation

The wired remote of the GTH400 can be installed either in dash or under dash.

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