Issue 1, September 2007 Model 233 User Guide
Page 6 Studio Technologies, Inc.
of capabilities many other specialized
“behind-the-scenes” applications can
also be implemented.
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
standard. An LED indicator serves as an
aid for optimizing the preamplifier’s gain
setting. The output of the microphone pre-
amplifier is used by the main output as well
as being routed to the compressor circuit
that supports the talkback functions.

Main Output

The Model 233 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.
The output circuitry features a high-
performance output transformer
expressly designed for professional
audio applications.

Talkback Functions

The talkback functions are intended
to provide personnel associated with
production trucks, control rooms, live-
performance, and sports venues with
talent-originated cue signals. The Model
233 contains two pushbutton switches
that control the talkback functions. As-
sociated with each pushbutton switch is a
dedicated line-level talkback output. Each
pushbutton switch can also be configured
to send audio to one specific channel
associated with the Model 233’s dual-
channel intercom interface.
The line-level talkback outputs are
transformer-coupled with a +4 dBu
nominal signal level. They contain resis-
tors in series with the output connectors,
allowing line-level talkback outputs from
multiple units to be directly “summed.”
For non-on-air applications, a special
Model 233 feature set can be enabled by
placing the unit in its “production” mode.
This software-based mode allows the
Figure 2. Model 233 back panel