6
| JL Audio - XD300/1v2 Owner’s Manual
TURN-ON OPTIONS
The XD300/1v2 can be switched on and off
using one of three methods, determined by the
position of the amplifier’s “Turn-On Mode”
switch. Please read these options and decide
which is best suited for your specific system.
1) +12V remote turn-on lead
2) Signal-sensing turn-on circuit.
3) DC offset-sensing turn-on circuit
+12 V Remote Turn-On: This is the preferred
method for turning the amplifier on/off. The
amplifier will turn on when +12 V is present at
its “Remote” input and turn off when +12 V is
switched off. This +12 V remote turn-on signal
is typically controlled by a source unit’s remote
turn-on wire. The XD300/1v2’s “Remote” turn-
on connector will accept 18 AWG – 12 AWG
wire. To connect the remote turn-on wire to
the amplifier, first back out the set screw on the
top of the terminal block, using the supplied 2.5
mm hex wrench. Strip 1/2 inch (12mm) of wire
and insert the bare wire into the terminal block,
seating it firmly so that no bare wire is exposed.
While holding the wire in the terminal, tighten
the set screw firmly, taking care not to strip the
head of the screw and making sure that the wire
is firmly gripped by the set screw.
If a source unit does not have a dedicated
remote turn-on output, consider one of the
following alternative turn-on options:
These methods are useful when a conventional
+12 V remote turn-on signal is not available in a
system. These allow you to operate the amplifier
without having to locate a remote turn-on lead at
the source unit, which can be very useful when
interfacing the amplifier with OEM (factory)
audio systems that do not use conven12 V
turn-on leads.
Depending on the characteristics of the audio
signal, one of the following methods may work
better than the other. We recommend trying DC
Offset-Sensing first as it does not require a long
delay to turn the system off after the signal is
shut off.
DC Offset-Sensing: The amplifier will turn on
and off by detecting the presence of a very small
DC signal (offset) that is typical in the audio
output of most OEM (factory) source units and
amplifiers. The amplifier will turn on and off in
reaction to the presence or absence of this DC
Offset. The sensitivity of this circuit is designed
for high-level (speaker level) signals, not for low-
level (preamp level) signals. The circuit senses
the left-channel signal only.
Signal-Sensing: The amplifier will turn on
and off by detecting the presence of a full-range
audio signal at its left-channel input. After
approximately 30 seconds, the amplifier will shut
off. The sensitivity of this circuit is designed for
high-level (speaker level) signals, not for low-level
(preamp level) signals. The circuit is tuned to
react to signals at mid-range frequencies. This
prevents false switching from signals created by
moving loudspeakers that are in parallel with the
amplifier’s input signal.
In signal sensing and DC offset sensing
applications, the amplifier’s “Remote” turn-on
terminal becomes a remote turn-on output.
This allows the XD300/1v2 to turn on other
amplifiers in the audio system that do not have
signal sensing or DC offset sensing. Of course,
the XD300/1v2 must be the first amplifier in the
signal path for this to function properly.
INPUT SECTION
The XD300/1v2 employs a differential-
balanced input topology that provides the user
with a high degree of input flexibility, while
retaining superior noise rejection. This type of
circuit also allows the XD300/1v2 to accept high-
voltage inputs from factory source unit outputs
without excessive distortion or noise problems.
