Page 31
CE-Series
Amps with an Attitude!
On the other hand, an unbalanced circuit usually holds one
leg at ground potential, while the second leg is “hot.” Unbal-
anced line is less expensive, but is much more susceptible to
noise, and is not usually used in professional applications. For
the cleanest signal, without unwanted hum and buzz, bal-
anced line is always recommended. It is especially helpful if
you have a long cable run (over 10 feet (3 m)), since noise is
easily introduced into long, unbalanced lines.
–
+
3
1
2
GND
FROM
SOURCE
INPUT
BALANCED
+
–
SHIELD
FROM
SOURCE
INPUT
UNBALANCED
+
SHIELD
+
3
1
2
SHIELD
4 Other Issues
Balancing the Line
A balanced audio circuit typically will have both positive (+)
and negative (–) legs of the circuit isolated from the ground
circuit. These balanced legs exhibit identical impedance char-
acteristics with respect to ground, and may also carry the au-
dio signal at the same level, but with opposite polarities. This
results in a line that offers excellent rejection of unwanted
noise.
1/4-inch XLR
Tip = + = Pin 2
Ring = – = Pin 3
Sleeve = = Pin 1
Fig. 4.1
Balanced &
Unbalanced
Input Wiring
Fig. 4.2
Polarity
Conversions
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