Datasheet

wide range of sources. The configuration choices can be made
either locally or by way of the STcontroller software applica
-
tion. The preamplifier of each channel can be selected for 0 dB
of gain to support line-level sources or 10 to 60 dB of gain, in
1-dB steps, for microphones. A source of P48 phantom power
can be enabled to power condenser microphones. In addition,
a high-pass filter (HPF) function can be enabled as required
to reduce the presence of unwanted low-frequency content
typically associated with hum, rumble, or wind noise.
Compatible signal sources include dynamic, ribbon, and
phantom-powered condenser (capacitor) microphones. The
preamplifier gain settings of 0 dB and the range of 10 to 20 dB
were specifically included to support connection of balanced
and unbalanced line-level signals that are commonly provided
by professional and semi-professional audio equipment. Typi
-
cal nominal levels for these sources would be +4 dBu and
–10 dBV, respectively. Devices providing these analog signal
sources could include audio consoles, wireless microphone
receivers, and broadcast playback equipment.
For front-panel space efficiency the eight mic/line input chan
-
nels share a common configuration section which includes
seven pushbutton switches and an OLED display. The buttons
allow rapid local selection of the preamplifier gain as well as
controlling the on/off status of the P48 phantom power and
high-pass filter (HPF) functions. The OLED display allows
the preamplifier gain of each mic/line input channel to be
observed. Audio channel level metering is also provided as
part of the OLED display’s resources. The “virtual” meters
are calibrated in dBFS which can assist users in optimizing the
preamplifier gain settings which in turn will provide the best
possible conversion from the analog to the digital domain. LED
indicators associated with each mic/line input channel provide
the on/off status of the P48 phantom power and high-pass
filter (HPF) functions.
The mic/line inputs are electronically balanced (differential),
capacitor-coupled, and ESD (static) protected for reliable
operation in a variety of demanding applications. Extensive
filtering minimizes the chance that radio frequency (RF)
energy will cause interference. The inputs are protected from
damage should a moderate DC voltage be accidentally con
-
nected. The sum of these characteristics makes the mic/line
inputs suitable for use in studio and mobile facilities as well
as field-deployed environments.
The eight 3-pin female XLR connectors associated with the
Model 5418’s mic/line inputs were specifically located on
the front panel. This can eliminate the need for an external
I/O or “patch” panel, allowing signal sources and their as
-
sociated interconnecting cables to be rapidly connected and
disconnected as required. Rather than being “buried” in the
back of a rack enclosure the Model 5418 provides convenient
access to the mic/line input connectors and their associated
configuration buttons, indicators, and OLED display.
The audio performance of the Model 5418’s mic/line inputs
is very good. Low-noise, wide dynamic-range preamplifier
circuits ensure that input audio quality is preserved. The
P48 phantom power source is extremely low noise, allow
-
ing optimal microphone operation and imparting little signal
degradation. The outputs of the preamplifiers are routed to
high-performance analog-to-digital conversion (ADC) sections
that support various sampling rates and a bit depth of 24. A
precision voltage-reference circuit helps the ADC circuitry
perform highly accurate signal conversion. The audio signals,
now in the digital domain, are connected to the Dante interface
section where they are packetized and prepared for transport
over Ethernet.
Analog Outputs
The Model 5418 provides eight general-purpose line-level
analog output channels. Each of the analog output channels
can be individually configured to use as its input source a
Dante input (receiver) channel, a mic/line input channel, one
of the monitor output channels, or a 1 kHz sine-wave tone.
In most applications an input (receiver) channel associated
with the unit’s Dante interface will serve as the audio source.
The Dante Controller software application would be used to
select the source which originates from an output (transmitter)
channel on an associated piece of Dante equipment.
Another configuration choice allows signals associated with
any of the mic/line inputs to serve as the source for an analog
output channel. The selected signal would be post (after) the
mic/line input circuitry and provide a broadcast-style “hot mic”
line-level analog output version of its associated mic/line input
signal. To allow connection to inputs on amplified speakers
any analog output channel can be configured to use either of
the two monitor outputs as its source. For troubleshooting
purposes a 1 kHz sine-wave tone at –20 dBFS can be assigned
as the source for any analog output channel. This would result
in an analog output level of +4 dBu.
Studio Technologies, Inc. Model 5418 Mic/Line Interface, Issue 1, Page 3