Balanced & Unbalanced Input Wiring - Crown K Series Reference Manual

Fig. 4.1
Balanced &
Unbalanced
Input Wiring
Page 26
tors illuminate and no steps are taken to reduce the input signal or
attempts made to improve air circulation. The amplifier will not
shut down, you'll still be rockin' with plenty of distortion-free
decibility!
Balancing the Line
A balanced audio circuit typically will have both positive (+)
and negative (–) legs of the circuit that are isolated from the
ground circuit. These balanced legs exhibit identical imped-
ance characteristics with respect to ground, and may also
carry the audio signal at the same level, but with opposite po-
larities. This results in a line that offers excellent rejection of
unwanted noise.
BALANCED
GND
1
–
3
2 +
INPUT
+
–
SHIELD
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.
Getting Rid Of Dr. Hum and Mr. Buzz
If you have noticeable hum or buzz in your system, you may
want to check your cable connections to see if the unwanted
noise is being introduced via a ground loop. To determine the
proper wiring, first check whether the output from your source
is unbalanced or balanced (if you don't know, refer to the unit's
back panel or instruction manual). If the source is balanced,
refer to Figure 4.2; if it is unbalanced refer to Figure 4.3. Next,
K-Series Balanced Current Amplifier™
1
2
FROM
INPUT
SOURCE
UNBALANCED
SHIELD
3
+
FROM
SOURCE
+
SHIELD