Studio Technologies 5120 2011 - Manual (Page 9)

Model 5120 User Guide Issue 3, November 2011
Studio Technologies, Inc. Page 9
Model 5120
Line/IFB Output Module
Operation
The Model 5120 is designed for con-
tinuous operation with no adjustment or
maintenance required. On the input side,
maintaining the correct levels coming from
the analog or digital audio sources is very
important. This will ensure proper signal
levels are being presented to users and
maintain optimal audio fidelity. The audio
meters and IFB output voltage status LED
function (“DC PIN 2”) will assist users in
confirming that correct operation is taking
place. In addition, the under-voltage shut-
down function will help to protect the IFB
output circuitry should a fault condition be
detected.
The line outputs are designed for general-
purpose use and can drive balanced or
unbalanced loads. The IFB output is intend-
ed to directly support listen-only beltpacks
such as the Models 32A, 33A, and 34
Talent Amplifiers from Studio Technologies.
Level Meters
The two audio level meters on the Model
5120 are calibrated differently from typical
“VU” meter scales. Their “steps” are labeled
in reference to the nominal level of both the
line and IFB outputs. For 5120S modules
the green “0” LED corresponds to a +4 dBu
line output and a –10 dBu IFB output au-
dio level. For 5120E modules the “0” LED
corresponds to 0 dBu and –10 dBu output
levels respectively. The ballistics of the me-
ters is also different, being a cross between
VU and peak.
The four green LEDs indicate that the out-
put levels are in the normal range. The two
yellow LEDs light when the signals are 6 to
approximately 17 dB above the reference
level. The red LEDs, labeled “18,” will light
when the output levels have come close to,
or have reached, the maximum level. An
optimal input signal will result in the four
green LEDs lighting almost solidly with the
yellow LEDs lighting only on peak signals.
The red LED lighting is not a good thing
and indicates that the input signal level
must be reduced.
Line Outputs
The line outputs are designed for general-
purpose use which could include connect-
ing to externally-powered listen-only user
beltpacks, transmitters associated with
wireless in-ear monitors, audio consoles,
or amplified speakers. The audio qual-
ity is such that using the line outputs for
on-air applications would be appropriate.
The outputs are analog, electronically bal-
anced, capacitor coupled, and will perform
optimally when driving loads of 2000 (2 k)
ohms or greater. When using Model 5120S
(SMPTE-compatible) modules the line out-
put level will be +4 dBu when a signal at
reference level is applied to the input. (An
SMPTE reference level signal will either be
+4 dBu analog or –20 dBFS digital.) With
Model 5120E (EBU-compatible) modules
the line output level will be 0 dBu when an
input signal at reference level is applied.
(An EBU reference level will either be
0 dBu analog or –18 dBFS digital.)
The Model 5120 provides two 3-pin male
XLR connectors for interfacing with asso-
ciated equipment. Pin 2 should be con-
nected as signal + (high), pin 3 as signal
– (low), and pin 1 as common/shield. To
connect to an unbalanced load use pin 2
as signal + (high) and pin 1 as low/shield.
Pin 3 should be left unconnected. To clar-
ify, for correct unbalanced operation it is
important not to connect pin 3 to anything,
e.g., do not connect pins 1 and 3 together.