Manual

USBPre 2 User Guide and Technical Information
14
Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.
Outputs and Monitoring
Headphone Output
The USBPre 2 has a high current headphone amplifier for monitoring analog input audio, computer
audio, or a mix of both. The Headphone Volume Control adjusts the level of the signal to the head-
phones. The Headphone Volume Control knob and the Output Gain Control knob can be swapped
with the back panel DIP Switches. See DIP Switch Options.
Caution: The USBPre 2 is capable of driving headphones to dangerously high levels. Be aware of head-
phone level controls at all times.
Use the Monitor Mix Control on the front panel to adjust the mix between direct audio from the in-
puts (fully counter-clockwise) and output audio from the computer (fully clockwise). The signal for
input audio is derived from the inputs before analog-to-digital conversion.
Headphone Mono mode sums the input signals from both inputs into a mono mix for the head-
phones. To toggle Headphone Mono mode, push the Headphone Mono button on the front panel.
The Headphone Mono LED will illuminate when Headphone Mono mode is active. Optionally, the
stereo signal from the computer can also be summed when Headphone Mono mode is engaged. See
DIP Switch Options.
Main Outputs
Signal level at the balanced XLR outputs and unbalanced AUX outputs is adjusted with the Output
Gain Control. The signal source for the outputs is the output audio from the computer. This source
can be changed to the same source as the headphone output with the back panel DIP Switches. The
balanced XLR outputs are set to line level by default and can be set to mic level with the back panel
DIP switches. See DIP Switch Options.
The Windows Volume Control (controlled with the “speaker” icon in the system tray) and the Mac
volume control affect the level of the computer’s output audio before it reaches the USBPre. It is gener-
ally best practice to set the volume control to 100% and make adjustments to the output level with the
USBPre 2’s Output Gain Control.
Digital Outputs
When the USBPre 2 is used as a computer audio interface, the sample rate of the digital outputs
(Coaxial S/PDIF and optical TOSLINK) is determined by the application settings on the computer. In
Stand-alone mode, the sample rate is determined by the position of the back panel DIP switches.
Optical (TOSLINK) outputs are inoperable at 192 kHz sample rate.
Metering
The USBPre 2 features a 23-segment, 2 channel LED meter. The meter displays both the peak level
of source audio and average (VU) levels simultaneously. 0 dB on the meter is calibrated to 0 dBFS
signal coming from the computer.
The current source signal for the meter is indicated by an illuminated LED next the Meter Source
Button. The meter source can be toggled by pushing the Meter Source Button. When the meter