Studio Technologies 230 2014 - Manual (Page 45)

Model 230 User Guide Issue 9, November 2014
Studio Technologies, Inc. Page 45
pin 2, signal low/shield to pin 3, and leave
pin 1 left unterminated (“floating”).
Several things are worth mentioning. As
previously discussed, the nominal output
level of this additional line-level talkback
output is –10 dBu. This is significantly less
than the nominal level of the Model 230’s
line-level talkback output. The audio qual-
ity is similar, only the level is different. Also
note that if a line output card is installed its
output, as well as its associated talkback-
to-intercom channel, will always operate
in tandem. Independent control is not
possible, nor should it be required.
Direct Microphone Output
The Model 230’s main output is intended
to be used as the on-air, stadium an-
nouncement, or other primary audio feed.
The path from the unit’s microphone input
connector to the main output connector is
by way of active circuitry. A low noise, low
distortion microphone preamplifier stage,
“clickless” audio switching, and a high-
quality transformer-coupled output circuit
work together in achieving excellent per-
formance. The nominal level of the main
output is –2 dBu, allowing interconnection
with related devices at a near-standard
“line” level. However, there may be ap-
plications where an output that directly re-
lates to the connected microphone would
be beneficial. The Model 230 has made
provision to accomplish this by using the
optional direct microphone output card.
This card, available from Studio Tech-
nologies and purchased separately (part
number 31058), is mounted in a spare
connector location available on the Model
230’s back panel. With this addition both
an “active” main output and a “passive”
direct microphone output will be available.
Of course, both outputs provide quiet
noise-free on/off (“muting”) control.
The primary application for the direct mi-
crophone output is when the Model 230
is integrated into a system that includes
a high-performance microphone pre-
amplifier. This preamplifier may be part
of a stand-alone voice-processor unit, or
a microphone input associated with an
audio console. Engineering personnel
may prefer the sonic characteristics of the
external microphone preamp over that of
the one integrated into the Model 230.
It’s important to note that the direct mi-
crophone output card provides a direct
“metallic” path from the microphone input
to the external preamplifier circuitry. It is
not simply an audio “pad” (attenuator) that
reduces the level of the main output from
“line” to “mic.” The Model 230’s auxiliary
relay contact, along with circuitry on the
direct microphone output card, provide
click-free muting of the signal.
The direct microphone output card con-
tains only passive circuitry. A 3-pin male
XLR connector is provided for the output
signal. A resistor and large electrolytic
capacitor form the muting circuit. This
arrangement allows muting to take place
without disturbing phantom-power that
may be enabled to support a condenser
microphone. The direct microphone
output card also contacts two 3-posi-
tion header connectors. These interface
with “headers” on the Model 230’s main
printed circuit board assembly, providing
access to the microphone input connector
and auxiliary relay contact.
The direct microphone output card kit
contains a printed circuit board assembly,
two interconnecting cables, and mounting