Specifications

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I. Introduction
The AES-302 Digital Audio System comprises of a two input AES compatible switcher, four output
digital audio DA and digital to analog converter. The unit also has status and diagnostic error indicators for
troubleshooting. The AES-302 is intended for use at unattended transmitter sites or for virtually any digital
switching, distribution and/or D/A conversion application. The unit has the capability to automatically
switch inputs upon detection of loss of clock, digital error flags and/or silence sense. In addition to these
features, the unit can function as an interface standards converter. As shipped from the factory the unit is
supplied with XLR balanced connectors. The unit can be configured with any combination of input/output
connectors if desired. Default factory supplied connections are XLR. Optical and S.P.D.I.F – RCA
connections are available as options.
II. Unpacking and Inspection
Carefully inspect the unit after unpacking and make certain that no damage has occurred during shipping.
If damage is noted, contact the shipper immediately and file a claim for damages. Each unit is carefully
packed and carries full insurance against damage. Inspect the packing list and make sure that the contents
of the package match those described on the packing list.
III. Installation and Connections
Select a space in suitable E.I.A. standard rack to locate the unit. Determine the local electrical power
supply voltage and select the proper input voltage at the rear of the unit. As supplied from the factory, your
AES-302 is setup for 120 V.A.C. 60 Hz unless noted otherwise. To change the input voltage to 240 volts,
simply slide the plastic cover and remove the p.c. board in the E.M.I. protected power entry module and
flip it so that “240 Volts” is legible from the rear as the board is placed back into the power entry module.
No replacement of the fuse is necessary as the fuse supplied is rated for up to 250 V.A.C. operation. The
unit is rated to run from 120/240 V.A.C. at 50 to 60 Hz operation. Make connections to the unit following
good engineering practice. Supply power to the unit utilizing a three pronged grounded outlet. Do no lift
the electrical ground to the unit at the power receptacle as this will result in a safety hazard. In the event of
ground loops, lift the ground at the offending connection only. Make certain that the unit is afforded proper
ventilation in the area of the top cover vent.
A. Digital Interface
Unless ordered as an option Inputs to the switcher are balanced XLR connectors conforming to the AES
standard. The unit may be ordered with SPDIF or optical interface. Each XLR connection is terminated at
110 ohms as per the standard. SPDIF inputs are terminated at 75 0hms. The balanced digital outputs are
also XLR connections, which provide 110-ohm transformer coupled source impedance as per the standard.
Again as an option outputs can be configured for SPDIF or optical interface.
B. Analog Interface
There is provided on the rear of the unit a left/right balanced analog output. This output is suitable for
driving 600-ohm balanced lines and is short circuit protected. A headphone jack and volume control
buttons are provided on the front panel of the unit for confidence monitoring of the incoming feed.
IV. Features and Operation
The AES-302 Digital Audio System is designed to select one of two AES3 compatible feeds and route it to
up to four balanced, optical or unbalanced digital loads. It also contains a high quality digital to analog