JL Audio A1800 - Manual (Page 7)

APPENDIX B:
Precise Frequency Selection Chart
“FILTER FREQ” AMP FILTER
Detent Panel Actual
Number
Marking Freq.
Full counter-clockwise: 42
01 . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
02 . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
03 . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
04 . . . . . . . . . . . “40” . . . . . . . . . . . .42
05 . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
06 . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
07 . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
08 . . . . . . . . . . . “45” . . . . . . . . . . . .47
09 . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
10 . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
11. . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
12 . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
13 . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
14 . . . . . . . . . . . “55” . . . . . . . . . . . .57
15 . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
16 . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
17 . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
18 . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
19 . . . . . . . . . . . “65” . . . . . . . . . . . .67
20 . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
21 . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
22 . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
23 . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
24 . . . . . . . . . . . “80” . . . . . . . . . . . .83
25 . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
26 . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
27 . . . . . . . . . . . . . . . . . . . . . . . . . . . .96
28 . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
29 . . . . . . . . . . .“100” . . . . . . . . . . 108
30 . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
31 . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
32 . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
33 . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
34 . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
35 . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
36 . . . . . . . . . . .“200” . . . . . . . . . . 193
37 . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
38 . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
39 . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Full-clockwise: 198
JL AUDIO A1800 13
APPENDIX C:
A1800 Specifications
General Specifications:
Recommended Fuse Value: 80A
Recommended Fuse Type: AGU, AFS, ANL or MaxiFuse™
Input Sections:
No. of Inputs: One Stereo Pair
Input Type: Differential-balanced with RCA jack inputs
Input Range: Switchable from 200mV - 2V RMS to
800mV - 8V RMS
Amplifier Section:
Amplifier Topology: H-Bridge, Class D Mono
with patented discrete drive circuitry
Power Supply: Unregulated MOSFET switching type
Rated Power at 12.5 V with less than
0.08% THD+Noise (20-250 Hz):
480W RMS x 1 @ 4 ohms, 800W RMS x 1 @ 2 ohms
Rated Power @ 14.4V with less than
1% THD + Noise (20-250 Hz):
640W RMS x 1 @ 4 ohms, 1000W RMS x 1 @ 2 ohms
Signal to Noise Ratio: >95 dB referred to rated power
(A-weighted, 20 Hz - 20 kHz noise bandwidth)
Frequency Response: 10 - 250 Hz (+0, -1 dB)
Damping Factor: >500 @ 4 ohms/50 Hz, >250 @ 2
ohms/50 Hz
Amplifier Filter:
Amplifier Low-Pass Filter: State-variable, 12 dB/octave
Butterworth or 24 dB/octave Linkwitz-Riley with
continuously variable cutoff frequency selection
from 40 - 200 Hz. Defeatable.
Preamp Output:
Buffered pass-through type.
Dimensions(LxWxH):
15.75" x 9.25" x 2.50" (400mm x 235mm x 63.5mm)
12 JL AUDIO A1800
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 A1800).
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 A1800) at 3/4
source unit volume.
7) Connect the AC voltmeter to the speaker output
connectors of the amplifier. Make sure you test
the voltage at the correct connectors (+ and –).
8) Increase the “Input Sens.” control until the
target voltage is observed with the voltmeter.
9) Once you have adjusted the A1800 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. Impedance Target AC Voltage
4Ω 43.8 V
3Ω 42.0 V
2Ω 40.0 V
Due to ongoing product development, all specifications are subject to
change without notice.