Benchmark Media Systems, Inc.
Page 7 of 39
REAR PANEL:
OUTPUT LEVEL SWITCH – Three Position Toggle:
Calibrated
(UP)
– Analog output levels are controlled by 10-turn rear-panel trim controls
Off
(CENTER)
– Analog outputs are muted, headphone outputs remain active
Variable
(DOWN)
– Analog output levels are controlled by front-panel gain control
The
Output Level
switch does not affect the operation of the headphone jacks (the headphone outputs are never
disabled and the headphone level is always controlled from the front panel).
CALIBRATION POTENTIOMETERS:
The calibration potentiometers are 10-turn trimmers and are accessible through the rear panel using a small
screwdriver. These trimmers provide a 2 dB per rotation adjustment with a total control range of + 9 to +29 dBu at
0 dBFS (full-scale digital input). Factory calibration has been set so that the output level at the balanced XLR
connectors is +4 dBu @ -0 dBFS (+4 dBu when the digital input signal is at -0 dBFS, and -16 dBu at -20 dBFS).
This is lower than the most common reference level for studio applications, but is appropriate for most powered
monitors.
The factory-preset levels may be increased by 5 dB or decreased by 15 dB in order to conform
to other studio reference levels. This range of levels is also well suited for direct connection to the balanced line-
level inputs on most power amplifiers. Most professional equipment will work well at these levels.
Note:
The
Calibration Potentiometers
have no effect on the output levels when this switch is set to
Variable
.
Caution:
Most powered studio monitors require signal levels that are much lower than standard studio levels. All
DAC1 converters produced after 12/01/02 are equipped with internal jumper-selected 10, 20, and 30 dB
attenuators. DAC1 converters produced prior to 12/01/02 were shipped with external 20 dB attenuator cables.
Most powered monitors will require 20 dB attenuation when connected directly to the DAC1 XLR outputs.
Caution:
Do not set the ‘Output Level Switch’ to ‘Calibrated’ if you
are directly driving a power amplifier or powered
speakers. The ‘Calibrated’ setting produces an output that
is near full-volume and may damage your speakers.
If directly connecting the DAC1 to a power amplifier or powered speakers, it is highly
recommended to start in “variable” mode with the volume knob at ‘full-off’ (7 o’ clock),
then slowly increase to a comfortable level.
