Studio Technologies 210 2008 - Manual (Page 11)

Model 210 User Guide Issue 4, October 2008
Studio Technologies, Inc. Page 11
Main Output
The main output is intended to be the
“on-air” signal that connects to the input
of an audio console. The output is trans-
former balanced with a nominal signal lev-
el of –2 dBu. The actual level will depend
on the gain setting of the microphone
preamplifier, sensitivity of the microphone,
and how loudly the talent speaks into
the microphone. The transformer used
in the main output is intended for profes-
sional broadcast applications. It has a low
source impedance and can drive lengthy
cable runs with no difficulty. It is capable
of driving 600 ohm loads but performs
best with loads of 2 k ohms or greater.
(This should not prove to be an issue as
virtually all contemporary audio equipment
has a relatively high input impedance.)
As the secondary winding of the output
transformer connects directly to the main
output connector, care should be taken
so that DC voltage is never present on the
interconnecting cable.
The main output is interfaced by means
of a 3-pin male XLR-type connector
located on the Model 210’s back panel.
The interconnecting cable’s mating
connector (female) should be wired so
that signal high (+ or hot) is on pin 2 and
signal low (– or cold) is on pin 3. The
cable’s shield can be connected to pin
1, but it will have no function. To limit the
chance of grounding interaction between
the Model 210 and connected equipment,
pin 1 on the main output’s connector is
isolated from any point in the Model 210.
The fact that pin 1 “floats” will minimize
the chance of hums, noises, or buzzes
being present on the equipment connect-
ed to the main output.
Talkback Output
The talkback output is intended for con-
nection to control rooms, production
trailers, or other locations where talent-
originated voice cues are required. The
talkback output is transformer balanced
with a nominal level of +4 dBu. To en-
hance talkback audio quality, the com-
pressor circuit controls the dynamic range
of the signal coming from the microphone
preamplifier.
For protection against accidental connec-
tion to cables that have DC power present,
the talkback output is capacitor coupled.
In series with the talkback output leads
are 300 ohm resistors, making the ef-
fective output impedance approximately
600 ohms. These resistors create a pas-
sive summing network, allowing talkback
outputs on multiple Model 210 units to be
connected together.
The talkback output is connected by way
of a 3-pin male XLR-type connector which
is located on the Model 210’s back panel.
A mating connector (female) should be
prepared so that signal high (+ or hot) is
expected on pin 2. Signal low (– or cold)
should be expected on pin 3. The cable’s
shield can be connected to pin 1. But,
like the main output, in order to minimize
the chance that ground-interaction prob-
lems will arise, pin 1 of the talkback out-
put connector is isolated from the Model
210’s chassis and circuitry. By making pin
1 “float,” an often-feared “ground loop”
problem shouldn’t arise.
The talkback output is intended to drive
lengthy cable runs that are frequently part
of a remote broadcast application. While
the output circuitry is not intended to be
“on-air” quality, overall audio performance
should be very good. Devices connected