Speaker Outputs; Bridging Considerations - JL Audio JD 400/4 Owner's Manual

SPEAKER OUTPUTS

The JD400/4's speaker outputs are designed
to accept 16 AWG - 8 AWG wire. To connect the
speaker wires to the amplifier, first back out the
set screws on the top of the terminal block, using
the supplied 2.5 mm hex wrench. Strip 1/2 inch
(12 mm) of insulation from the end of each 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 place, tighten the set
screw firmly, taking care not to strip the head of
the screw.
Each pair of the JD400/4's channels is designed
to deliver power into speaker loads equal to or
greater than 2 ohms per channel when using
a "stereo" configuration and speaker loads
equal to or greater than 4 ohms per bridged
pair when using a "bridged" configuration.
Speaker loads below 2 ohms nominal per
channel (or 4 ohms bridged) are not
recommended and may cause the amplifier
to enter a protection mode.
10

BRIDGING CONSIDERATIONS

Bridging is the practice of combining the
output of two amplifier channels to drive a single
load. When bridged, each channel produces
signals of equal magnitude, but opposite polarity.
The combined output of the two channels
provides twice the output voltage available from
a single channel. The JD400/4 has been designed
for bridging of its channel pairs without the need
for input inversion adaptors.
To bridge a pair of channels, use the
"Left +" and "Right –" speaker connectors only
(the "Left –" and "Right +" remain unused).
When bridged, each channel will deliver
optimum power into a 4 ohm load.
!
I M P O R TA N T !
When a pair of the JD400/4's channels are
bridged, they will deliver 200W x 1 into a 4 ohm
load or 150W x 1 into an 8 ohm load. Operating
a pair of bridged channels into a load lower than
4 ohms is not recommended and will cause the
amplifier to enter into protection mode.
!
I M P O R TA N T !
Any bridged channel pair must be fed by both
Input Channels corresponding to it (Left and
Right). Failure to do so will result in significant
audible distortion.
When a pair of the JD400/4's channels are
operating in bridged mode, the output will be in
mono (only one channel). This mono channel
can contain right channel only information,
left channel only information or the sum of
the information from both the right and left
channels. In order to achieve one of these options,
configure the inputs to that pair of channels in
one of these two ways:
1) Left Channel Only or Right Channel Only
Information: If you wish to send a left-only
or right-only signal to a pair of the JD400/4's
channels, use a "Y-Adaptor" to split the single
channel signal into both left (CH. 1&3) and
JL Audio