Studio Technologies 68A 2001 - Manual (Page 14)

Issue 1, March 2001 Model 68A/69A User Guide
Page 14 Studio Technologies, Inc.
for Surround
receive units set for 220/240V. Before
connecting the Model 68A to AC mains
power, check that it is configured to match
the local mains voltage. Look on the back
panel (adjacent to the power entry connec-
tor) for the factory-configured voltage.
Note that an incorrect configuration could
prevent operation, or cause damage to the
unit. Should it be necessary to change the
unit’s operating voltage it must be per-
formed only at the factory or by an autho-
rized service technician.
The Model 68A uses an IEC-standard
connector to mate with the AC mains
cord. The wire colors in the AC mains
cord should conform to the internationally
recognized CEE color code and must
be wired accordingly:
Connection Wire Color
Neutral (N) Light Blue
Line (L) Brown
Protective Earth (E) Green/Yellow
Safety Warning: The Model 68A does
not contain an AC mains disconnect
switch. As such, the AC mains cord
plug serves as the disconnection
device. Safety considerations require
that the plug and associated outlet be
easily accessible to allow rapid discon-
nection of AC mains power should it
prove necessary.
As soon as AC mains power is applied,
the Model 68A’s power present LED
will light. The Model 69A will go through
a power-up sequence, lighting each LED
in secession. The data active LED on
the Model 68A will briefly light upon
completion of the Model 69A’s power-up
sequence.
Configuration
After the physical installation has been
completed, several configuration issues
must be addressed. On the Model 68A the
surround and stereo inputs must be cali-
brated using the trim potentiometers. The
operating parameters of the system should
be set using the Model 69A Control
Console’s configuration mode.
Level Calibration
Sixteen 15-turn trim potentiometers are
located on the front panel of the Model
68A Central Controller. Taking time to
carefully adjust the trim pots will ensure
that accurate monitoring can take place.
Each trim pot allows input signals with a
nominal level of –12dBV to +6dBu to be
utilized. With care, it’s easy to calibrate
the surround and stereo inputs to within
one-quarter of a dB of the desired value.
The monitor outputs are used as the
measuring point when adjusting the trim
pots. A laboratory-grade audio level meter,
or equivalent, is required for accurate
calibration. In addition, the audio sources
connected to the inputs must be able to
generate continuous audio signals at their
nominal operating level.
Procedure
This procedure will calibrate the surround
and stereo input channels. The trim pots
will be adjusted in groups corresponding
to their associated input sources.
1. Begin by turning the audio amplifiers
or amplified speakers to their off state.
This will protect the loudspeakers and
the operator’s ears from possible
damage.