Berkeley Audio Design Alpha USB User Manual

QUICK USER GUIDE v1.2.2
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Berkeley Audio Design Alpha USB
The Alpha USB is an asynchronous High Speed USB to digital audio interface designed to
provide the highest possible audio quality from computer audio sources. Please take a few
minutes to familiarize yourself with this User Guide before connecting power to the Alpha USB.
Doing so will help ensure the best possible performance.

INSTALLATION

The Alpha USB should be installed in a space with several inches of clearance above, behind
and on both sides of the chassis to provide adequate ventilation. Avoid placement directly
above other equipment that produces significant heat.

Power Connection

The Alpha USB is designed to run continuously when connected to AC mains power. It has no
power switch and as soon as AC power is connected the unit is powered on. Units for sale in
the United States are set internally for 120VAC operation. An Alpha USB dealer can select
240VAC operation for use outside of the United States by setting an internal switch and adding
a 240V label to the rear panel. 100VAC operation requires a specific power transformer. The
AC power fuse used for all mains voltages is a 5 x 20mm Cartridge, .05A Time Lag (Slo-Blo)
Littelfuse 0218.050MXP or 0218.050HXP.
Powering the Alpha USB from the same power source as the D to A converter and other
analog components is recommended. Its linear power supply has several layers of isolation
between the power cord and the digital circuitry, and it performs best when treated as an
analog component. The computer should be powered from a separate circuit whenever
possible to minimize power line noise.

Signal Connections

Alpha USB Rear Panel
The Alpha USB has a High Speed USB 2.0 input data connection and has switch selectable
output signal type – either coaxial SPDIF using a BNC connector or balanced AES using an
XLR connector. Sampling rates up to 192 kHz and word lengths up to 24 bit are supported.

Lead Dress

It is good practice to keep various types of signal and power cables physically separated from
each other. This is especially important for the USB cable to the computer. It should be routed
away from the chassis of the Alpha USB and any other component or cable that is part of the
audio system. 1.5 meters is a good default length for USB, SPDIF and AES cables.
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