JL Audio J2320.4 - Manual (Page 7)

12 JL Audio 13
aPPendix b:
J2-320.4 specifications
general specifications:
Recommended Fuse Value: 60A
Recommended Fuse Type: AFS, AGU or MaxiFuse™ at
battery, 2 x 30A ATC fuses on amplifier chassis
input sections:
No. of Inputs: Two Stereo Pairs
Low-Level Inputs: Single-ended with RCA jack inputs
Low-Level Input Range: 200mV - 4V RMS
High-Level Inputs: Single-ended with molded connector
High-Level Input Range: 2V - 10V RMS
amplifier section:
Amplifier Topology: Class B with
complementary bi-polar output stage
Power Supply: PWM switching type, unregulated
Rated Power with less than 1% THD (14.4V supply):
Stereo, all channels driven:
60W RMS x 4 @ 4 ohms, 80W RMS x 4 @ 2 ohms
Bridged, all channels driven:
120W RMS x 2 @ 8 ohms, 160W RMS x 2 @ 4 ohms
Frequency Response: 10 Hz - 25 kHz +/- 0.5 dB
Crossover sections:
Filter Type: 12dB/octave Butterworth
with continuously variable low-pass cutoff frequency
selection from 40-150 Hz and high-pass cutoff frequency
selection from 60Hz - 1.2 kHz.
Configurable as Low-Pass or High-Pass. Defeatable.
Preamp output:
2-Channel, pass-through with unity gain, RCA-type jacks.
dimensions (lxwxH):
15.40" x 9.60" x 2.15" (391 mm x 244 mm x 55 mm)
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 connected, set the amplifier’s Remote Bass
Control at maximum (full clockwise).
3) 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) 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 amplifier 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.
Due to ongoing product development, all specifications are subject to
change without notice.
nom.
impedance
target aC voltage
stereo bridged
8Ω 15.5 V 31 V
6Ω 15.5 V 28 V
4Ω 15.5 V 25 V
3Ω 14 V not recommended
2Ω 12.5 V not recommended