Signal Levels; Chassis Grounding - Art Model 442 User Manual

Balanced output requires using Pin 2 of the XLR or the tip of the 1/4" TRS as output Hi (+) and using
pin 3 of the XLR or the ring of the 1/4" TRS as Lo (-). It does not require pin 1 or signal ground. The
signal exists differentially between the two balanced leads. Ground is used only for shielding to
prevent potential hum. Paralleling inputs and outputs may be accomplished by using any of the three
connectors. Note: 1/4" TRS are normally used.

SIGNAL LEVELS

Signal levels from -10 dBu to +4 dBu are considered normal and 20dB of headroom exists above
these levels. Do not connect microphones directly to the equalizer. Microphones require a preamp.

CHASSIS GROUNDING

The Model 442 and 452 Equalizers are equipped with a rear panel Ground Lift switch. After setting up
your system, if the system exhibits excessive hum or buzzing, the problem may be a ground incom-
patibility between your equalizer and other equipment in the same system. There are several combi-
nations that can be attempted. NOTE: ALWAYS TURN YOUR AMPLIFIERS DOWN BEFORE
CHANGING GROUNDS. Try different combinations of lifting grounds on units that are supplied with
ground lift switches or make sure all chassis are connected to earth ground, either through the AC
Power cord ground or by the front panel rack mount screws.
OPERATING INSTRUCTIONS
Before starting to equalize your sound system there is some information you should know and proce-
dures you should follow. Your equalizer is equipped with a bypass switch. The bypass switch, when
activated, lights the LED and cancels all equalization settings while allowing signal to flow through the
unit at unity gain.
Also included is a range selection switch with LED indicators, 6dB =green, 12dB= yellow. In addition
to the range selection switch there is a level control potentiometer. The level control operates be-
tween off and +6dB. Note: If there is too much gain your equalizer has a red LED Clip indicator. The
Clip LED illuminates when signals reach 5dB prior to clipping. If this situation occurs and the overload
LED flashes occasionally, this is okay. However, if the overload LED is steadily on, you must readjust
the level control.
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