JL Audio G4500 owner manual Appendix a, Necessary Equipment, Nine-Step Procedure, Input Sections

Appendix A:

Input Sensitivity Level Setting Following the directions below will allow the

installer to adjust the input sensitivity of each amplifier channel pair simply and easily in just a few minutes using equipment which is commonly available in installation bays.

Necessary Equipment

•Digital AC Voltmeter

•CD with a sine-wave test tone recorded at

0 dB reference level in the frequency range to be amplified for that set of channels

(50 Hz for subwoofer channels, 1 kHz for a midrange application). Do not use attenuated test tones (-10 dB, -20 dB, etc.).

The Nine-Step Procedure

1)Disconnect the speaker(s) from the amplifier’s speaker output connectors.

2)Turn off all processing (bass/treble, loudness, EQ, etc.) on the source unit, processors (if used) and amplifier. Set fader control to center position and subwoofer level control to 3/4 of maximum (if used to feed the G4500).

3)Switch the “Input Voltage” switch to “Low” and turn the “Input Sens.” control all the way down.

4)Set the source unit volume to 3/4 of full volume. This will allow for reasonable gain overlap with moderate clipping at full volume.

5)Using the chart on this page, determine the target voltage for input sensitivity adjustment according to the nominal impedance of the speaker system connected to the amplifier outputs.

6)Verify that you have disconnected the speakers before proceeding. Play a track with an appropriate sine wave (within the frequency range to be amplified by the G4500) at 3/4 source unit volume.

7)Connect the AC voltmeter to the speaker output connectors of the amplifier. If the channel pair is operating in stereo, it is only necessary to measure one channel. If bridged, make sure you test the voltage at the correct connectors (L+ and R–).

8)Increase the “Input Sens.” control until the target voltage is observed with the voltmeter.

9)Once you have adjusted the G4500 to its maximum low-distortion output level, reconnect the speaker(s). The “Input Sens.” controls can now be adjusted downward if the amplifier requires attenuation to achieve the desired system balance.

Do not increase any “Input Sens.” setting for any amplifier channel or channel pair in the system beyond the maximum level established during this procedure. Doing so will result in audible distortion and possible speaker damage.

It will be necessary to re-adjust the “Input Sens.” for the affected channels if any equalizer boost is activated after setting the

“Input Sens.” with this procedure. This applies to any EQ boost circuit, including source unit tone controls or EQ circuits. EQ cuts will not require re-adjustment.

Nom.	Target AC Voltage
Impedance	Stereo	Bridged
8Ω	17..8 V	26..8 V
6Ω	17..8 V	25..6 V
4Ω	17..8 V	24..6 V
3Ω	17..3 V	not recommended
2Ω	15..8 V	not recommended

Appendix B: 

Precise Frequency Selection Chart

“Filter FREQ” AMP Filter

Detent Panel Actual

Number Marking Freq.

Full counter-clockwise: 53

01 .	. . . . . . . . . . . . . . . . .	53
02 .	. . . . . . “50”	.53. . . .
03 .	. . . . . . . . . . . . . . . . .	53
04 .	. . . . . . . . . . . . . . . . .	54
05 .	. . . . . . . . . . . . . . . . .	54
06 .	. . . . . . . . . . . . . . . . .	55
07 .	. . . . . . . . . . . . . . . . .	55
08 .	. . . . . . “55”	.56. . . .
09 .	. . . . . . . . . . . . . . . . .	56
10 .	. . . . . . . . . . . . . . . . .	57
11 .	. . . . . . . . . . . . . . . . .	58
12 .	. . . . . . . . . . . . . . . . .	59
13 .	. . . . . . . . . . . . . . . . .	62
14 .	. . . . . . “60”	.65. . . .
15 .	. . . . . . . . . . . . . . . . .	65
16 .	. . . . . . . . . . . . . . . . .	66
17 .	. . . . . . . . . . . . . . . . .	70
18 .	. . . . . . . . . . . . . . . . .	73
19 .	. . . . . . . . . . . . . . . . .	77
20 .	. . . . . . “80”	.81. . . .
21 .	. . . . . . . . . . . . . . . . .	84
22 .	. . . . . . . . . . . . . . . . .	88
23 .	. . . . . . . . . . . . . . . . .	94
24 .	. . . . . . . . . . . . . . . . .	101
25 .	. . . . . . . . . . . . . . . . .	104
26 .	. . . . . .“120”. . . . . . . . . 115. . . .
27 .	. . . . . . . . . . . . . . . . .	118
28 .	. . . . . . . . . . . . . . . . .	128
29 .	. . . . . . . . . . . . . . . . .	137
30 .	. . . . . . . . . . . . . . . . .	146
31 .	. . . . . . . . . . . . . . . . .	164
32 .	. . . . . .“150”. . . . . . . . . 177. . . .
33 .	. . . . . . . . . . . . . . . . .	193
34 .	. . . . . . . . . . . . . . . . .	197
35 .	. . . . . . . . . . . . . . . . .	209
36 .	. . . . . . . . . . . . . . . . .	213
37 .	. . . . . . . . . . . . . . . . .	216
38 .	. . . . . .“200”. . . . . . . . . 218. . . .
39 .	. . . . . . . . . . . . . . . . .	225
	Full-clockwise: 225

Appendix C:

G4500 Specifications

General Specifications:

Recommended Fuse Value: 50A

Recommended Fuse Type: AFS, AGU or MaxiFuse™

Input Sections:

No. of Inputs: Two Stereo Pairs

Input Type: Differential-balanced with RCA jack inputs

Input Range: Switchable from 200mV - 2V RMS to 800mV - 8V RMS

Amplifier Section:

Amplifier Topology: Class A/B with patented Absolute Symmetry™ dual N-Channel MOSFET output design Power Supply: Unregulated MOSFET switching type Rated Power at 14.4V with less than

1% THD+Noise (20Hz - 20 kHz) Stereo, all channels driven:

80W RMS x 4 @ 4 ohms, 125W RMS x 4 @ 2 ohms Bridged, all channels driven:

160W RMS x 2 @ 8 ohms, 250W RMS x 2 @ 4 ohms Rated Power @ 12.5V with less than

1% THD + Noise (20Hz - 20 kHz) Stereo, all channels driven:

60W RMS x 4 @ 4 ohms, 90W RMS x 4 @ 2 ohms Rated Power Bridged, all channels driven:

120W RMS x 2 @ 8 ohms, 180W RMS x 2 @ 4 ohms Signal to Noise Ratio: >104 dB referred to rated power (A-weighted, 20 Hz-20 kHz noise bandwidth) Frequency Response: 10 Hz - 25 kHz (+0, -1dB) Damping Factor: >200 @ 4 ohms per ch../50 Hz, >100 @ 2 ohms per ch.. /50 Hz

Slew Rate: ± 22V/µs

Amplifier Filter:

Filter Type: State-variable, 12dB/octave Butterworth with continuously variable cutoff frequency selection from 50-200 Hz..

Configurable as Low-Pass or High-Pass.. Defeatable..

Preamp Output:

Pass-through type, buffered..

Switch-selectable to pass signal from CH 1&2 inputs only or from all four inputs (summed)..

Dimensions(LxWxH):

13.8" x 9.25" x 2.50" (350mm x 235mm x 63.5mm)

Due to ongoing product development, all specifications are subject to change without notice..

14 JL AUDIO G4500 JL AUDIO G4500 15