Shure SCM268E, User Manual, Page: 5 / 28

5
Gain Control
Input Gain
The gain control knobs 1-4, located on the front panel, adjust the gain for
both microphone and auxiliary-level inputs of channels 1-4 (see Figure1).
For example, the channel 1 gain control is used for both the channel 1
microphone input (MIC LEVEL INPUT 1) and the channel 1 auxiliary level
input (AUX LEVEL INPUT 1). The auxiliary gain control knob (AUX IN)
affects only the auxiliary input (AUX IN).
Output Gain
The master output gain control knob (MASTER) adjusts gain to both the
XLR balanced output (MIC/LINE LEVEL) and the auxiliary level output
(AUX LEVEL).
Gain Control
Channel 1
Channel 2
Channel 3
Channel 4
Auxiliary Channel
Master Output
Figure 1
Output Level Meter
The six LEDs on the front panel labeled OUTPUT LEVEL METER illumi-
nate to reflect the peak level of the mixed output signal from the SCM268
(in reference to balanced line output) in dBu (0 dBu = 0.775 V).
Use the master gain control (MASTER) to adjust peak levels, as indicat-
ed by the LEDs. The red LED illuminates when the output is 2 dB below
clipping.
GREEN-nominal RED-Clip
Peak in dBL
Phantom Power
When the phantom power switch on the back panel is on (12V
PHANTOM-ON), the SCM268 provides 12 V of phantom power to each
XLR microphone input. The switch is recessed to prevent accidental en-
gagement. Most condenser microphones require phantom power. Use it
when connecting these types of microphones to the SCM268.
Phantom power does not affect the operation of balanced dynamic micro-
phones. With phantom power on, they can be connected to the SCM268
in combination with condenser microphones that do use it.
OFF ON
Phantom Power Switch
Output Level Switch
The output level switch on the back panel (MIC/LINE OUT) sets the level
of the balanced XLR output. When set to MIC, it reduces the output by
about 50 dB. Set the switch so that the output level matches the input
level of the device to which you are connecting the SCM268. The switch is
recessed to prevent accidental engagement.
The output level switch does not affect the auxiliary output (AUX OUT)
level.
LINE MIC
Output Level Switch
Connections
The following diagram illustrates a few of the many types of connections
possible with the SCM268. Note that nothing is connected to the channel
4 microphone input (MIC LEVEL INPUT 4). This is because channel 4 is
being used for the consumer-level equipment connected to the channel
4 auxiliary level input (AUX LEVEL INPUT 4). Connecting both auxiliary
level and microphone level inputs to a single channel is not recommended
because the SCM268 would not be able to independently mix the two
sources.
Â
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AUX IN CHANNEL 4 CHANNEL 3 CHANNEL 2 CHANNEL 1
CD Player
AM/FM Receiver
Tape Deck
VCR
Power Supply
Amplifier
Loudspeakers
70 V P.A.