Model 85 User Guide
Issue 3, November 1999
Studio Technologies, Inc.
Page 7
The Model 85 AES/EBU Digital Audio
Distribution Amplifier is designed by Studio
Technologies as part of its Studio Tools
group of audio support products.
Designed for a wide variety of recording,
production, broadcast, and duplication
applications, the Model 85 has two
AES/EBU inputs and eight AES/EBU
outputs. All Model 85 functions meet or
exceed the performance of the most
expensive “high end” audio equipment.
What This User Guide Covers
This User Guide is designed to assist
you when installing, configuring, and
using the Model 85 AES/EBU Digital
Audio Distribution Amplifier.
System Overview
The Model 85 provides two AES/EBU
digital audio inputs and eight AES/EBU
outputs. Each of the eight outputs provides
a fully isolated reproduction of either input.
Output source selection is provided by
front-panel DIP switches. The Model 85
allows AES/EBU signals to be distributed
to multiple inputs (receivers) without incur-
ring data transmission errors.
A typical application would use the Model
85 to distribute the AES/EBU output of a
digital audio workstation (DAW) to devices
such as DAT or CD recorders, audio/video
storage systems, tie lines to other facili-
ties, etc.
Single rack space mounting, standard
XLR-type connectors, and status LEDs
make installation of the Model 85 a simple
job. The AC mains input power is factory
configured for 100, 120, or 220/240V
operation. Components and construction
standards make the Model 85 suitable for
continuous operation, even for on-air
broadcast applications.
AES/EBU Inputs
Each of the two inputs have transformer
coupling and DC voltage blocking. An LED
status indicator is associated with each
input, lighting whenever digital information
is present.
AES/EBU Outputs
The Model 85 contains eight independent
AES/EBU output sections. The rugged
output circuits feature transformer cou-
pling. For flexibility, each of the eight
outputs can individually select input A or
B as its source. This allows the Model 85
to act as a single 1x8 distribution amplifier
(DA), or two fully independent DAs.
Example configurations include creating
a dual 1x4 DA, or a combination 1x3 DA
and 1x5 DA.
Technical Background
The original AES/EBU specification
(AES3-1985) called for a single transmitter
to drive up to three receivers. In practice
this proved to make data transmission
susceptible to errors as an impedance
mismatch is created whenever more than
one receiver is driven. The revised edition
of the specification (AES3-1992) advises
that a single transmitter should drive only
a single receiver. The Model 85 addresses
this requirement in a simple, reliable
manner. Up to eight identical, but fully
isolated, “copies” of the original source
are created.
Introduction
