Studio Technologies 200 - Manual (Page 8)

Model 200 User Guide Issue 3, August 2004
Studio Technologies, Inc. Page 9
Microphone interconnection is made by
way of a 3-pin female XLR-type connector
which is located on the Model 200’s back
panel. The mating connector (male) should
be wired so that pin 2 is signal high (+ or
hot), pin 3 is signal low (– or cold), and pin
1 is shield. It’s possible that an unbalanced
microphone will also work correctly. In this
case, the mating connector (male) should
be wired so that pin 2 is signal high (+ or
hot), and signal common/shield is connect-
ed to both pins 1 and 3.
The Model 200 is not compatible with
unbalanced “electret”-type microphones
that require a source of low-voltage DC for
operation. These microphones, sometimes
found in low-cost headsets, are not gener-
ally suitable for on-air or other demanding
applications.
As of the writing date of this user guide, the
Sennheiser HMD25 headset is very popu-
lar for on-air sports broadcast use. A fine
product, it works very well with the Model
200. Note that adding the suffix “-XQ” to the
headset’s part number (HMD25-XQ) speci-
fies a 3-pin male XLR- type connector for
the dynamic microphone and a ¼-inch 3-
conductor plug for the stereo headphones.
This configuration is very useful, allowing
the headset to work directly “out of the box”
with the Model 200.
If the writer may digress for a moment to
recount a story… an audio dealer once
shared a secret with me concerning
headsets. He loved selling name-brand
but “lower-end” (less expensive) headsets,
which he did by the veritable “boatload.”
Why? Because they usually broke soon
after going into service! He knew that on a
regular basis he’d receive orders for more of
them. Had these users, from the beginning,
purchased only premium-quality headsets,
their total cost of ownership would have
been much less. Enough said…
Headphone Output
The Model 200’s headphone output is com-
patible with stereo or mono headphones,
headsets, or earpieces. Connecting devices
with a nominal impedance of 100 ohms or
greater is preferred. This shouldn’t prove to
be an issue as essentially all contemporary
devices will meet this condition.
Devices are connected to the headphone
output by way of a ¼-inch 3-conductor
phone jack which is located on the Model
200’s back panel. As is standard for stereo
headphones, the left output is connected
to the “tip” lead of the ¼-inch headphone
jack. The right output is connected to the
“ring” lead of the jack. Common for both
outputs is connected to the “sleeve” lead.
Devices with ¼-inch 2-conductor “mono”
plugs can also be used with the Model
200’s headphone output. In this arrange-
ment only the tip lead (left channel) will
be active. The 2-conductor plug will physi-
cally connect (“short”) the ring lead (right
channel) to the sleeve lead (common).
Technically this won’t damage the circuitry
associated with the right-channel head-
phone output. (51 ohm protection resistors
are electrically in series with the headphone
output circuits.) However energy will be
wasted if an audio signal coming out of
the right channel goes into a “dead short.”
There are several ways of limiting the
chance that this condition will occur. The
first way is to disconnect or “un-route”
any audio source going to channel 2 of
the connected IFB circuit. Channel 2 audio
is found on pin 3 of the IFB input XLR-type
connector. The second way is pretty obvi-
ous—keep the right channel level control