Crest Audio X 18R, Owner'S Manual, Page: 31 / 56

Stereo Input Channel
2
Rear Panel Features
+48 V On
+48 volts DC is applied equally (thru current-limiting resistors) to pins 2 and 3 on
both the L & R mic-input XLR connectors. This feature is used with condenser micro-
phones and active direct boxes that require an external DC voltage (phantom
power) in order to operate. For dynamic or ribbon mics, phantom voltage is not
required and should be switched OFF.
NOTE 1: Operating this switch (On or Off) causes large voltage swings to occur
at the input of the mic preamp. Care should be taken to insure that the channel is
muted or the main faders are pulled down to prevent this POP from getting to
someone’s ears.
XLR (Mic) Input Jack
These balanced, female XLRs accept a low-impedance microphone signal or a line-level
signal depending on the position of the LINE INPUT switch on the front panel.
Pin-2 is Positive Input, Pin-3 is Negative Input, Pin-1 is Chassis Ground.
Input impedance is 4K balanced.
Line Input Jack
Line-level signals, balanced or unbalanced, may be brought into the input channel
through these 1/4” TRS jacks. The LINE switch (front panel) must be pressed for this
jack to be active. The XLR jacks are normaled to the switching contacts of these jacks. If
nothing is plugged into the jack, a padded XLR signal is available to the channel when
the LINE switch is depressed. This allows the LINE switch to perform a dual function:
XLR pad if nothing is plugged into the Line jack, or XLR(Mic)/Line input selection if the
jack is being used.
Tip is Positive Input, Ring is Negative Input, Sleeve is Chassis Ground.
Input impedance is 20K balanced.
p. 31