Studio Technologies 200 - Manual (Page 9)

Issue 3, August 2004 Model 200 User Guide
Page 10 Studio Technologies, Inc.
in its fully counterclockwise position. A
third way is preferred, but unfortunately
might prove to be impractical out in the
field. It would mandate the use of ¼-inch
3-conductor plugs on all devices, stereo or
monaural, that are to be connected. Stereo
headphones or headsets would connect
in the usual way: left channel on tip, right
channel on ring, and common on sleeve.
But monaural devices would connect only
to the tip and sleeve leads; the ring lead
would remain unconnected. This would
ensure that the Model 200’s right-channel
headphone output would never be shorted.
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 transformer
balanced with a nominal signal level of
–2 dBu. The actual level will depend on the
gain setting of the microphone preampli-
fier, sensitivity of the microphone, and how
loudly the talent speaks into the micro-
phone. The transformer used in the main
output is intended for professional broad-
cast applications. It has a low source im-
pedance 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 200’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 200 and
connected equipment, pin 1 on the main
output’s connector is isolated from any
point in the Model 200. The fact that pin 1
“floats” will minimize the chance of hums,
noises, or buzzes being present on the
equipment connected to the main output.
Talkback Output
The talkback output is intended for
connection 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. The actual
level will depend upon the output level
of the connected microphone and the
amount of gain selected for the micro-
phone 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 effec-
tive output impedance approximately
600 ohms. These resistors allow talkback
outputs on multiple Model 200 units to
be connected together, creating a passive
summing network.
The talkback output is connected by way
of a 3-pin male XLR-type connector which
is located on the Model 200’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, to minimize the chance