Studio Technologies 220 2013 - Manual (Page 6)

Issue 5, February 2013 Model 220 User Guide
Page 6 Studio Technologies, Inc.
System Features
Microphone Input
A high-performance microphone preampli-
fier circuit provides low-noise/low-distortion
amplification over a 20 to 60 dB gain range.
The gain is adjustable in 10 dB steps. The
input is compatible with balanced dynamic
and condenser microphones. The micro-
phone power source is 48 volts nominal
and meets the worldwide P48 phantom
power standard. An LED indicator serves
as an aid for optimizing the setting of the
preamplifier’s gain. The output of the mi-
crophone preamplifier is used by the main
output as well as being routed to the com-
pressor circuit that supports the talkback
functions.
Main Output
The Model 220 provides a main output that
is designed to serve as the on-air, stadium
announcement, or other primary audio
feed. Nominally –2 dBu, it is designed as a
fully professional interface with high output
capability, low distortion, and low noise. It
features a high-performance output trans-
former expressly designed for professional
audio applications.
Talkback Outputs
The two talkback outputs are intended to
provide production trucks, control rooms,
or support personnel with talent-originated
cue signals. These outputs are transformer-
coupled with +4 dBu nominal signal levels.
They contain resistors in series with their
output connector, allowing the talkback
outputs from multiple units to be directly
“summed.”
For non-on-air applications, a special
Model 220 feature can be enabled, placing
the unit in a “production” mode. This allows
the main output to be used as a third talk-
back output. In this configuration the unit
can be even more powerful when used in
corporate or theatrical events, for example
serving as a master console for a produc-
tion director.
Dynamic Range Control
A studio-quality compressor circuit is pro-
vided to control the dynamic range of the
signal coming from the microphone pre-
amplifier. Far from a simple “clipper,” the
circuit utilizes a sophisticated laser-trimmed
voltage-controlled-amplifier (VCA) inte-
grated circuit for quiet, low-distortion level
control. The signal from the compressor
Figure 2. Model 220 back panel