4
tem is noise free.
Mono Operation
The CR12 can also be operated in mono by switching the mode switch to mono and connecting the input
signal to either the A or B input jack. This signal will be sent to both amplifiers. Each amplifier’s audio
level will be controlled by its corresponding gain control. You can use the remaining input jacks to “loop
through” to another amplifier or a piece of sound equipment.
Stereo Operation
The CR12 may be operated in stereo by switching the mode switch to stereo and connecting the “Left /
Right” stereo input signal to the A and B input jacks. Each gain control will adjust the audio level for its
corresponding amplifier channel. The input jacks for each channel are wired in parallel so that the unused
connector can be used to send the input signal to another amplifier or piece of sound equipment.
Bridged Operation
The CR12 may be operated in bridged mode by switching the mode switch to bridge and connecting the
input signal to either the A or B input jack. Channel A’s gain control is used to adjust the audio signal
level. The loudspeaker load is connected across the two red binding posts with the positive lead of the
loudspeaker wire connected to the red channel A binding post.
Outputs
Two types of output connectors are on the output of the CR12. Heavy-duty binding posts accept a banana
plug, forked-lug or bare wire connections. When the amplifier is used in stereo (or mono mode), connect
the loudspeaker to the red and black binding posts. With the positive wire, from the loudspeaker, connect-
ing to the red binding post, and the negative wire to the black binding post. For bridged mode operation,
the speaker load is connected across the two red binding posts with the positive lead of the speaker wire
connected to the red channel (A) binding post. The diagrams on the sidebar show the different loudspeak-
er wiring configurations. The other connector is a ¼ inch phone jack for quick setups and teardowns. Use
a mono ¼ inch phone plug with the tip of the plug wired to the positive connector and the sleeve of the
phone plug wired to the negative connector of the loudspeaker.
Each channel of the CR12 delivers up to 575 watts per channel into a 4-ohm loudspeaker. Wiring two 8-
ohm speakers to one channel will look like a 4-ohm loudspeaker to the amplifier and each 8-ohm loud-
speaker will receive 287 watts. In bridge mode the CR12 drives up to 1150 watts into an 8-ohm loudspeaker.
Gain Controls
The CR12’s gain controls are located on the back of the amplifier. This
prevents tampering with the gain controls when the amplifier is rack
mounted. The gain controls are calibrated in dB (decibels), corresponding
to the audio voltage present at the speaker output jacks. Where many
amplifiers are used in an installation, the gain controls scaled in dB allow
the user to precisely set the audio output level of one CR12 amplifier
channel relative to the other CR12 amplifier channels. This only works if
the amplifiers are receiving the same amplitude of input audio signal. The
0 db, or “full” position, of the gain control refers to 48 volts RMS (which
equals 575 watts into 4-ohms) on the output of the amplifier when a 1.4 volt RMS voltage is present at the
input jacks. Placing the gain control in the –3dB position with 1.4 volt RMS voltage present at the input
jacks will result in a 34 volt signal (which equals 288 watts into 4-ohms) at the speaker output.
Speaker
Configurations
