Studio Technologies M233-01151 - Manual (Page 13)

Model 233 User Guide Issue 5, November 2014
Studio Technologies, Inc. Page 13
console to be directly connected. When
the configuration DIP switches are set for
0 dB (no gain) the nominal level of the
source audio signal should be approxi-
mately –2 dBu.
Microphone interconnection is made
by way of a 3-pin female XLR connec-
tor which is located on the Model 233’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 connec-
tor (male) should be wired so that pin 2
is signal high (+ or hot), and signal
common/shield is connected to both
pins 1 and 3.
The Model 233 is not compatible with
unbalanced “electret”-type microphones
that require a source of low-voltage DC
for operation. These microphones, some-
times found in low-cost headsets, are
not generally suitable for on-air or other
demanding applications.
As of the writing date of this user guide,
the Sennheiser HMD 26 headset is very
popular for on-air sports broadcasting
use. A fine product, it works very well with
the Model 233. Note that adding the suffix
“-XQ” to the headset’s full part number
(HMD 26-600-XQ) specifies a 3-pin male
XLR connector for the dynamic micro-
phone and a ¼-inch 3-conductor plug for
the stereo headphones. This configura-
tion is very useful, allowing the headset
to work directly “out of the box” with the
Model 233.
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 the “lower-end”
(less expensive) models of name-brand
headsets, which he did by the veritable
“boatload.” Why? Because these 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 233’s headphone output is
compatible with stereo or mono head-
phones, headsets, or earpieces. Connect-
ing devices with a nominal impedance
of 100 ohms or greater is preferred. This
shouldn’t be an issue as essentially all
contemporary devices already meet this
condition.
Devices are connected to the headphone
output by way of a ¼-inch 3-conductor
phone jack located on the Model 233’s
back panel. As is standard for stereo
headphones, the left channel is connected
to the “tip” lead of the ¼-inch headphone
jack. The right channel is connected to the
“ring” lead of the jack. Common for both
channels is connected to the “sleeve”
lead.
Devices with ¼-inch 2-conductor “mono”
plugs can also be used with the Model
233’s headphone output. In this arrange-
ment only the tip lead (left channel) will
be active. The 2-conductor plug will
physically connect (“short”) the ring lead
(right channel) to the sleeve lead (com-
mon). Technically this won’t damage the
circuitry associated with the right-channel
headphone output. (100 ohm protection
resistors are electrically in series with the
headphone output circuits.) However,
energy will be wasted if an audio signal