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 recom- mended to remove the resistor chip. Pull the resistor chip from the socket as shown in the figure below.
6. Adjusting the Gain
Before operating the GTQ amplifiers, recheck all wiring connections to make sure they are correct and secure. Be sure that a fuse (not included) is installed in the +12V line near the battery. Reconnect the negative ground
• The setting of the gain controls on the |
GTQ amplifiers is important to ensure |
proper performance, low noise levels, and |
maximum reliability in the system. |
Using a high signal level from the source |
and a low gain setting on the amplifier |
will help keep background noise levels in |
the system low. |
7. Typical Applications
The following diagrams show the most common basic system configurations of the GTQ amps. One or more of these building blocks may be combined to form elaborate system designs.
The GTQ amps use the terminology “Group 1” and “Group 2” to indicate the two main signal paths within the amplifi- er. Each “group” may consist of a mono bridged signal or a stereo pair of L+R signals depending on the system configuration.
AIR FLOW
AIR FLOW
System 1
| . | CA |
|
| NORTHRIDGE,JBLPC00108800REV | ||
| JBLINC | GTS600 | A |
CROSSOVER | PASS |
|
|
LOW FILTERFREQUENCYSELECTIONMODULE |
| ||
| C10 |
|
|
| C13 |
|
|
| PASS |
|
|
| HIGH FILTERFREQUENCYSELECTIONMODULE |
|
|
4. Place the new module in the socket |
making sure all pins are lined up with the |
socket holes. Press the module firmly into |
• To adjust a system using a single GTQ |
amplifier, start with both of the amplifier |
gain controls fully counterclockwise. Set |
all bass/treble or equalizer controls to |
their centered or bypassed positions. |
While listening carefully to the system |
output, adjust the volume control of the |
radio/tape deck to the point where you |
first begin to hear audible distortion. |
Use caution: excessive distortion can |
damage loudspeakers. Reduce the level |
just to the point where the distortion goes |
Active 3-way using outboard tweeter amplifier
|
| Speaker | Preamp | Group |
|
|
| Output | Output | 2 |
|
| Mode | CrossoverCrossover | Input | ||
GR 1 | Stereo | Low | High | — | 5k** |
GR 2 | Stereo | Low | High | GR 2 | 80Hz** |
*A single (mono) subwoofer may be used by setting GR 2 mode to "L+R."
**The crossover frequencies listed are suggestions. Actual crossover points should be determined from loudspeaker requirements.
Input
Front
GR 1 | GR 2 | GR 2 | GR 1 |
Pre Out | Input | Pre Out | Input |
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
away. If this setting does not provide ade- |
quate volume levels, gradually increase |
(turn clockwise) the gain control for the |
main (usually front) speaker groups on |
the GTQ amplifier until the system plays |
as loud as necessary or when the first |
STEREO AMP
– +
L
+
R
–
GTQ AMP
GR 1 | GR 2 |
– | + | – | + | + | – | + | – |
L |
|
| R | L |
|
| R |
Upgrade Steps” sections.
signs of distortion are heard. |
Tweeters | Midbass | Subwoofers* |
8