and other equipment which would otherwise show up
as hum. If the output is driving a device or amplifier
that has an unbalanced input, connect the -ve(cold) sig-
nal to the ground at the destination, not at the output of
your SPIRIT STUDIO console.
Polarity
Polarity
You will probably be familiar with the concept of polar-
ity in electrical signals and this is of particular
importance to balanced audio signals. Just as a bal-
anced signal is highly effective at cancelling out
unwanted interference, so two microphones picking up
the same signal can cancel out, or cause serious deg-
radation of the signal if one of the cables has the +ve
and -ve wires reversed. This phase reversal can be a
real problem when microphones are close together and
you should therefore take care always to connect pins
correctly when wiring audio cables.
+
+
+
+
+
+
-
-
-
Source
Source
Source
Input
Input
Input
GND
LINK
GND
LINK
GND
LINK
BALANCED TO BALANCED
UNBALANCED TO BALANCED
UNBALANCED TO UNBALANCED
If ground link absent, or mains earth isolated from
source ground, then connect shield at both ends
Grounding and
Grounding and
Shielding
Shielding
For optimum performance it is vital that all signals are
referenced to a solid, noise-free earthing point and that
all signal cables have their screens connected to
ground. To avoid earth loops, use balanced connec-
tions where possible and ensure that all cable screens
and other signal earths are connected to ground only at
their source and not at both ends.
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