Studio Technologies 78 User Manual
Model 80 Stereo Analog
Audio Distribution Amplifier
User Guide
Issue 4, March 1997
This User Guide is applicable for serial numbers:
Model 80 M80-00273 and later
Copyright © 1997 by Studio Technologies, Inc., all rights reserved
5520 West Touhy Avenue
Skokie, Illinois 60077 U.S.A.
Telephone (847) 676-9177
Fax (847) 982-0747
www.studio-tech.com
50200-397, Issue 4
Table of Contents
Foreword...................................................................... 5
Introduction .................................................................. 7
What This User Guide Covers ................................. 7
System Overview ..................................................... 7
System Features ...................................................... 7
Installation .................................................................... 9
Configuration ............................................................... 11
Operation ..................................................................... 12
Troubleshooting........................................................... 12
Technical Notes ........................................................... 14
Circuit Description ....................................................... 15
Specifications............................................................... 19
Block Diagram
Schematic Diagram...........................Not included in PDF
Model 80 User Guide Issue 4, March 1997
Studio Technologies, Inc. Page 3
Foreword
I am pleased to present the Model 80 Stereo Analog Audio Distribution Amplifier. As both
president and owner of Studio Technologies, I take a very personal approach when designing products. Getting older (38 as of this writing) has increased my appreciation of the
more subtle things in lifebe they a part of nature or the nuances contained in a welldesigned piece of electronic equipment. Do the technical and operational aspects of a
product work together to feel right? A Studio Technologies design is ready to go only
when I am completely satisfied.
Many fine people worked toward making the Model 80 happen. Mitch Budniak (ace
consulting engineer) designed many of the circuits. Jim Cunningham contributed to the
analog design. Carrie Loving provided engineering support. Barbara Govednik coordinated the marketing communications aspects. Ben Kamen designed the automatic testing
routines. Al Lux designed the printed circuit board. Jim McGuire designed the graphics.
Fred Roeck performed the mechanical design. Joe Urbanczyk coordinated the safety
testing and agency approvals.
Additional thanks to Timothy Powell of Metro Mobile Recording, Glenview, Illinois, who
provided his excellent ears when issues of sonic quality arose. His extensive field and
studio experience was extremely helpful in keeping me on the audio straight and narrow.
Please contact me with your questions, comments, and suggestions. I can be reached by
voice at (847) 676-9177, fax at (847) 982-0747, or via the Internet @ www.studio-tech.com.
Sincerely,
Gordon K. Kapes
President
Model 80 User Guide Issue 4, March 1997
Studio Technologies, Inc. Page 5
Introduction
The Model 80 Stereo Analog Audio
Distribution Amplifier was developed by
Studio Technologies as part of its Studio
Tools group of audio support products.
The Model 80 is designed to work in a
large variety of applications. Specific
applications include audio production,
duplication, broadcast, and sound reinforcement. All Model 80 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 80 Stereo Analog Audio Distribution
Amplifier. It also contains detailed service
information, including block and schematic diagrams.
System Overview
The Model 80 from Studio Technologies,
Inc. is the first distribution amplifier that
meets the needs of the real world. The
stereo input is intended to connect to
virtually any line-level audio source. The
ExactCal input calibration section allows
for optimal audio performance over a 10
to +10dBu input level range. The eight
stereo outputs meet exacting professional
standards. Capable of driving balanced or
unbalanced loads, each output can drive
+26dBu into 600 ohms. Using front panel
switches, each output can be individually
configured for a nominal output level of
10 or +4dBu.
The front panel controls and LEDs make
installation and setup a simple job. The
AC mains input power is factory config-
ured for 100, 120 or 220/240V, 50/60Hz
operation. Components and construction
standards make the Model 80 suitable
for continuous operation, even for on-air
broadcast applications.
System Features
One Stereo Input
The differential input circuitry is compatible with balanced or unbalanced signals
having a nominal level range of 10 to
+10dBu. Using laser trimmed components, the input offers superior commonmode signal rejection. To achieve optimal
audio performance the ExactCal calibration section matches the specific input
level with the Model 80s internal gain
structure. Two controls and four LEDs
allow fast, precise calibration. Unlike other
distribution amplifiers, the Model 80
ensures that excellent audio performance
can be achieved with little or no hassle.
In addition to separate left and right input
connectors, two input loop-through connectors are also provided. This simple
feature can make installation with related
equipment much easier. The loop-through
connectors allow the Model 80s input
source to be connected to another Model
80 or to yet another device.
Eight Stereo Outputs
The Model 80 contains eight independent
stereo output sections. For compatibility
with a range of facilities, each output
section can be separately configured for
10 or +4dBu nominal output level. Each
output features an electronically balanced
circuit capable of driving balanced or
unbalanced loads. Operating an output
in an unbalanced configuration does not
cause its nominal output level to change.
Model 80 User Guide Issue 4, March 1997
Studio Technologies, Inc. Page 7
Short circuit resistant, the rugged output
circuits can drive full signal levels into 600
ohm or greater loads.
The Model 80s architecture precludes the
need for individual output-level trim potentiometers. With the input signal calibrated
using the ExactCal section, the eight
stereo outputs use 1%-tolerance components to provide precise 10 or +4dBu
outputs.
Audio Performance
The Model 80 is the result of exacting
circuit design combined with the latest
state-of-the-art components. Like all
Studio Technologies products, the Model
80 has survived tough listening evaluations by industry professionals. These
veterans had the ears to guide us in
achieving the right performance. The
outcome is a product that achieves
sonic excellence.
Design Philosophy
Most audio distribution amplifiers contain
a level trim adjustment on each output.
After careful study Studio Technologies
concluded that these adjustments confused, and often interfered with the
process of getting maximum audio
performance. After checking with personnel in the field, it became clear that what is
desired in virtually every distributionamplifier applications are multiple audio
outputs all operating at a standard reference level. By implementing the ExactCal
system, the Model 80s internal operating
level can be easily calibrated to match the
input signal. Once this input level matching is accomplished the eight stereo
outputs can be individually configured for
a 10 or +4dBu nominal operating level.
In conclusion, output trim pots are not
included on the Model 80 for the simple
reason that better audio performance can
be achieved without them!
Model 80 Front Panel
Power
present LED
Input
level control
Input level
calibration LEDs
Right input
trim control
10 or +4 output level
configuration switches
Model 80 Back Panel
AC mains
connection
Issue 4, March 1997 Model 80 User Guide
Page 8 Studio Technologies, Inc.
Stereo line-level
outputs
Loop through
output
Stereo line-level
input
Installation
In this section you will be installing the
Model 80 in an equipment rack. Audio
input and output connections will be made
using the Model 80s multitude of phone
jacks. AC mains power will be connected
to the Model 80.
System Components
The shipping carton contains a Model 80,
User Guide, and warranty card. Units
destined for North America are shipped
with an AC mains cord. Your dealer or
distributor will provide an AC mains cord
for non-North American destinations.
Balanced Connection
(Input & Output)
Ring ()
Tip ( + )
Sleeve
(Shield)
(Switchcraft No. 297, Neutrik NP3C, or equivalent)
Unbalanced Connection
(Input & Output)
Tip ( + )
Mounting the Model 80
The Model 80 requires one space in a
standard 19-inch (48.3cm) equipment
rack. It is desirable to locate the Model 80
to allow easy access to both the front and
the back panels. The back panel contains
the input and output connectors. The front
panel is used to access the calibration
controls and output-level switches. The
front panel also contains several LED
indicators. The Model 80 is secured to
the equipment rack using two mounting
screws per side.
Audio Inputs and Outputs
The Model 80s audio input and output
connections are made using ¼-inch
3-conductor phone jacks. The choice of
phone jacks was simply a matter of real
estate20 XLR connectors dont quite
fit on the back of a one rack-space unit!
Dont be concerned about damage to
your audio quality, the jacks used in the
Model 80 are manufactured by Neutrik
of Switzerland and feature gold-plated
contacts for excellent performance.
Sleeve
(Shield)
(Switchcraft No. 280, Neutrik NP2C, or equivalent)
Caution: For reliable audio interconnection, the plugs you use must comply with
industry standard RS-453. Switchcraft No.
297, Neutrik NP3C, or equivalent will work
correctly. Refer to the Technical Notes
section for details.
Audio Input
The Model 80 provides one stereo linelevel input. It is electronically balanced,
and is compatible with balanced or unbalanced signals that have a nominal level
range of
10 to +10dBu. The ExactCal section
allows precise level calibration with the
connected input signal. It is anticipated
that in most cases a stereo signal will be
connected to the input. The Model 80 can
also be used as a 1-input/16-output monaural distribution amplifier, or as a dual
1-input/8-output monaural distribution
amplifier.
Model 80 User Guide Issue 4, March 1997
Studio Technologies, Inc. Page 9
Loading...