Studio Technologies 5120 2014 - Manual (Page 9)

Model 5120 User Guide Issue 5, October 2014
Studio Technologies, Inc. Page 9
Model 5120
Line/IFB Output Module
Operation
The Model 5120 is designed for continuous
operation with no adjustment or mainte-
nance required. On the input side, main-
taining the correct levels coming from the
analog or digital audio sources is very im-
portant. 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 addi-
tion, the under-voltage shutdown 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 audio
level. For 5120E modules the “0” LED corre-
sponds to 0 dBu and –10 dBu output levels
respectively. The ballistics of the meters 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.