BSS Audio FCS-960 Owner's Manual - Manual (Page 9)

9
Audio Connections
4.4 Audio
Connections
Fig. 3 Input and Output
Connector Wiring
The FCS-930/960 audio inputs are RFI filtered and electronically
balanced, with the outputs electronically balanced and floating. They are
designed to operate at any signal level up to +20dBu and will drive into
loads of 600 ohms or greater. They will be ‘fuss free’, regardless of your
installation’s complexity. Figure 3 shows the connector wiring.
Note that pin 1 of the input XLR is not connected to ground.
Whether your system is wired to a ‘pin 3 hot’ or a ‘pin 2 hot’ convention
will not matter as long as your wiring to both the input and output 3 pin
XLR connectors are the same . As is common with all other BSS
equipment of this type, we follow the convention of ‘screen goes forward
with the signal’. Input cable screening therefore needs to be derived from
the signal source end as pin 1 is ground lifted for the inputs. You should
use high quality audio cable with 2 cores + screen for low noise and
reliability, and to side-step potential problems.
If the equipment driving the FCS-930/960 has only unbalanced outputs
then you will need to add a wire jumper such that the screen connection
on Pin 1 of the XLR is shorted to either Pin 2 OR Pin 3, depending on the
wiring convention of the unbalanced equipment.
If the equipment being connected to the FCS-930/960 outputs has only
unbalanced inputs, then we recommend that you still use a balanced
(i.e. 2 core shielded) cable. The interconnecting cable should have it’s
screen grounded by pin 1 of the FCS-930/960 output, the pin 3 output
should be connected to the unbalanced input 0v ground, and the pin 2
output should be connected to the live input. There should be no
connection between the cable screen and 0v/chassis ground connection
of the unbalanced equipment. Strict adherence to this will help to
eliminate potential ground loop hums by removing signal currents from
the cable screen.
Balanced Wiring
Unbalanced Wiring