Installation
LV3620
2–7
Shield not connected
at this end
+
–
+
Amplifier
Input
–
3–wire, grounded line cord or
other ground connection
Grounded
Input
Source
+
–
Floating
Input
Source
+
2–wire line cord
or battery power
Amplifier
Input
–
Illustration 2–6 Balanced input wiring
2.5.1 Input connection
The balanced input connector (three–terminal barrier block) has a nominal
impedance of 50 kilohms and will accept the line-level output of most devices.
A balanced (differential) signal input is recommended wherever possible.
Correct input wiring will depend on two factors:
• whether the input signals are balanced (differential) or unbalanced
(single-ended)
• whether the signal source floats or has a ground reference.
Other connection principles to remember:
• Use only shielded cable. Better cables have a higher density shield.
Spiral wrapped shield is not recommended.
• When using unbalanced lines, keep the cables as short as possible. Avoid
unbalanced cables over 10 feet in length.
• Do not run signal cables together with high-level wiring such as ac lines.
This reduces the chance of hum or noise being induced into the input
signals.
