Standby Mode; Hpa2 Tm Stereo Headphone Jacks; Volume Control - Benchmark DAC1 USB Instruction Manual

Standby Mode

The DAC1 USB features an automatic
standby mode that eliminates the need to
turn the converter on and off. Standby
Mode starts 15 seconds after a digital source
device is turned off, disconnected, or contains
errors that prevent D/A conversion. All status
LED's are off while in Standby Mode.
While in Standby Mode, the DAC1 USB
continues to monitor the selected digital input
and will immediately resume normal
operation when an error-free signal is
restored.
TM
HPA2 Stereo Headphone
Jacks
There are two stereo headphone jacks. The
left-hand jack is equipped with a switch that
mutes the XLR and RCA analog outputs when
a headphone plug is inserted. The right-hand
jack has no switch. This gives the user the
option of muting the analog outputs when
using headphones. Internal jumpers are
available to disable the headphone switch.
TIP: Use the left-hand jack when you
want to mute your playback system and
just listen to headphones. Use the right-
hand jack when you need to keep all
outputs active.
The dual jacks also allow two listeners to
monitor and compare notes on what is heard.
We recommend using identical headphones
because headphone sensitivities can differ
significantly. The Volume Control adjusts
the level at both jacks.
Because of the variations in headphone
sensitivity, the DAC1 USB features two gain
ranges for the headphone outputs. Our
DAC1 USB
Instruction Manual
experience with the classic DAC1 showed us
that most users cannot use the full output of
the HPA2™. These users benefit from a
reduced maximum gain. Internal jumpers
reduce the input to the HPA2™ by 10 dB and
place the Volume Control near 12 O'clock at
a comfortable listening level with most
headphones. These jumpers are factory
installed, but can be removed if a user needs
more output. Removing the jumpers
increases the gain to a level that is equal to
that of the classic DAC1.
TIP: For optimal L/R balance, the
headphone gain jumpers should be set
so that comfortable listening levels occur
when the 'Volume Control' is set above
th
the 10 detent.
Instructions for setting the headphone gain
range and headphone mute switch are
detailed in the 'Internal Settings' section of
this manual.

Volume Control

The front-panel Volume Control is a 41-
detent potentiometer (see 'Volume Control
Curve' in the 'Performance Graphs' section of
this manual).
The Volume Control always controls the
output level of the headphone jacks. It can
also be used to control the output levels of
the balanced XLR and unbalanced RCA analog
outputs when the rear-panel Output Level
Switch is set to Variable.
The XLR outputs have jumper-enabled pads
that can be used to optimize the gain
structure of the playback system.
TIP: For optimal L/R balance, and
minimal noise, the XLR gain jumpers
should be set so that comfortable
listening levels occur when the 'Volume
Control' is set above the 10
Instructions for setting the XLR pads are
detailed in the 'Internal Settings' section of
this manual. The DAC1 USB is shipped with
the XLR attenuation set to -20 dB.
Revision D
th
detent.
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