Studio Technologies 750 - Manual (Page 8)

Issue 3, May 1997 Model 750 User Guide
Page 8 Studio Technologies, Inc.
Model 750
System Features
Mic/Line Inputs
Four transformer-coupled input channels
are provided for connection to micro-
phone or line-level signals. The circuitry is
“ruggedized” for reliability under tough
operating conditions. A full set of features
is provided for each input channel, includ-
ing selectable input sensitivity, +48V
phantom power, low-cut filter, phase
reverse, level control, and pan pot. For
operator assistance, a bi-color LED pro-
vides signal present and peak level indica-
tion. Two illuminated push-button switches
control the routing of the input signal to
the main and auxiliary (AUX) audio buses.
For convenience the four mic/line input
sensitivity buttons, like all the Model 750’s
operator controls, are located on the front
panel.
Stereo Line Inputs
Two stereo line-level input channels are
provided, and are intended for connection
with audio signals associated with video
playback. The channels support “real
world” broadcast applications, where left
and right signals may, or may not, be an
actual stereo pair. Routing buttons allow
each left and right input to be assigned to
the left output bus, to the right output bus,
to both output buses, or muted. A level
control, along with a bi-color signal
present/peak LED, supports each left
and right input. Two illuminated buttons
control the routing of the signals to the
main and AUX audio buses.
Main Output
Signals from the mic/line input channels,
stereo line input channels, and the setup
section (discussed later) combine to
create the main audio output. The main
output bus is stereo, but can be used to
create two independent monaural audio
mixes. Two studio-quality, stereo limiter/
compressor circuits are provided to con-
trol the dynamic range of the main audio
bus. Far from a simple “clipper,” each
limiter/compressor circuit utilizes a sophis-
ticated laser-trimmed voltage-controlled
amplifier (VCA) integrated circuit for quiet,
low-distortion operation. For installation
flexibility, three sets of stereo output cir-
cuitry provide access to the main stereo
bus: two are electronically balanced, line-
level; the third is transformer-balanced,
with its output level selectable for mic or
line.
AUX Output
The Model 750 provides a second stereo
audio bus that can be configured to oper-
ate in either of two modes: as an auxiliary
(AUX) output or as a monitor interrupt
function. In the AUX output mode special
applications are easily supported, such as
creating a “mix-minus” feed or serving as
a second stereo output for on-air use.
Signals from the mic/line input channels,
stereo line input channels, and the setup
section can be assigned to the AUX bus.
Access to the AUX bus is provided by
means of an electronically-balanced, line-
level output.
In most cases, however, the AUX interrupt
mode will be selected, allowing the normal
monitor source to be interrupted and the
AUX signal monitored in its place. Model
750 operators will find this function ex-
tremely useful, enabling one or more of
the input channels, or the setup section,
to be monitored without interfering with
signals assigned to the main output bus.
Two DIP switches, accessible from the