Preamp Output - JL Audio MHD750/1 Owner's Manual

The amplifier will turn back on automatically
when voltage climbs back above 9 volts. This
shut-down and turn-on behavior may happen
in a rapid cycle when bass-heavy program
material causes a weak charging system to
momentarily dip too low. If this is happening
in your system, have your charging system
inspected to make sure it is working properly.
If no problem is found with the supply
voltage to the amplifier and you are
still seeing alternating Red and Green
on the "Status" LED, it is likely that the
amplifier is suffering from an internal
fault that requires factory service.
For more information on troubleshooting this
amplifier, refer to Appendix D (pages 18, 19).
serVicing Your Jl audio amPliFier
If your amplifier fails or malfunctions, please
return it to your authorized JL Audio dealer so
that it may be sent in to JL Audio for service.
There are no user serviceable parts or fuses inside
the amplifier. The unique nature of the circuitry
in the JL Audio amplifiers requires specifically
trained service personnel. Do not attempt
to service the amplifier yourself or through
unauthorized repair facilities. This will not only
void the warranty, but may result in the creation
of more problems within the amplifier.
If you have any questions about the installation or
setup of the amplifier not covered in this manual,
please contact your dealer or technical support.
Jl audio technical support:
(954) 443-1100
9:00 AM – 5:30 PM (Eastern Time Zone)
Monday - Friday
aPPendix a:
mHd750/1 specifications
Amplifier Topology: Class D, switching type with
patented Single-Cycle Control™ technology.
Power Supply: Pulse width modulation-regulated
switching power supply
Recommended Fuse Value / Type: 60A (AFS, AGU or
MaxiFuse™)
Rated Power:
750W RMS x 1 @ 1.5-4Ω (11V - 14.5V)
THD at Rated Power: <0.03% @ 4Ω
(Average at 1 kHz)
Signal to Noise Ratio (20 kHz Bandwidth):
Referred to Rated Power: 111 dBA
Referred to 1 Watt: 82.2 dBA
Frequency Response: 6 Hz - 8 kHz (+0, -1dB)
Damping Factor:
>500 @ 4Ω per ch. / 50 Hz
>250 @ 2Ω per ch. / 50 Hz
crossover Filter:
Filter Type: State-variable, 12 dB/octave Butterworth or
24 dB/octave Linkwitz-Riley
Filter Modes: Low-Pass or High-Pass, Defeatable.
Cutoff Freq. Range: Continuously variable, 50 - 500 Hz
input sections:
No. of Inputs: One Stereo Pair, sums to mono
Input Type: Differential-balanced with RCA jack inputs
Input Range: Switchable from 200mV - 2V RMS (Low)
to 800mV - 8V RMS (High)

Preamp output:

2-Channel, buffered pass-through type
chassis dimensions (lxwxH):
10.74 in. x 7.85 in. x 1.93 in. (273 mm x 199.5 mm x 49 mm)
Dimensions do not include connectors.
Due to ongoing product development, all specifications are subject to
change without notice.
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