Orban OPTIMOD-FM 5518, Operating Manual

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2-6
INSTALLATION ORBAN MODEL 5518
any studio-wiring standard: If pin 2 or 3 is considered LOW, the other pin
is automatically HIGH.
Analog Audio Input

Nominal input level between –9 dBu and +8 dBu will result in normal operation
of the 5518.
(0 dBu = 0.775Vrms. For this application, the dBm @600

scale on volt-
meters can be read as if it were calibrated in dBu.)

The peak input level that causes overload is +27.0 dBu.

The electronically balanced input uses an ultra-low-noise-and-distortion differ-
ential amplifier for best common mode rejection, and is compatible with most
professional and semi-professional audio equipment, balanced or unbalanced,
having a source impedance of 600

or less. The input is EMI suppressed.

Input connections are the same whether the driving source is balanced or unbal-
anced.

Connect the red (or white) wire to the pin on the XLR-type connector (#2 or #3)
that is considered
H
IGH by the standards of your organization. Connect the black
wire to the pin on the XLR-type connector (#3 or #2) that is considered
L
OW by
the standards of your organization.

In low RF fields (like a studio site not co-located with an RF transmitter), connect
the cable shield at 5518 input only—it should not be connected at the source
end. In high RF fields (like a transmitter site), also connect the shield to pin 1 of
the male XLR-type connector at the 5518 input.

If the output of the driving unit is unbalanced and does not have separate
C
HASSIS
G
ROUND
and (–) (or
L
OW
) output terminals, connect both the shield and
the black wire to the common (–) or ground terminal of the driving unit.
Analog Audio Output

Electronically balanced and floating outputs simulate a true transformer output.
The source impedance is 50

. The output is capable of driving loads of 600

or
higher; the AO 100% control can adjust the 100% modulation level over a –6
dBu to +24 dBu range. The outputs are EMI suppressed.

If an unbalanced output is required (to drive unbalanced inputs of other equip-
ment), it should be taken between pin 2 and pin 3 of the XLR-type connector.
Connect the
L
OW pin of the XLR-type connector (#3 or #2, depending on your
organization’s standards) to circuit ground; take the
H
IGH
output from the re-
maining pin. No special precautions are required even though one side of the
output is grounded.