User manual

8.3 Shielding/Grounding of Audio Equipment
The shield of any audio connection should be connected at
one end only. If not, ground loops and high frequency
crosstalk could result. Connect the shield (as a general
rule) to the signal source (output) of anything. In high
R.F. area's it is wise to ground the other end of the
shield wire via a O.Oluf capacitor. This will short circuit
the R.F. but will not affect audio frequencies.
8.4 Typical Interface Situation Table
Output
Unbalanced
Unbalanced
Unbalanced
Balanced
Balanced
Balanced
Differential
Differential
Differential
Input
Unbalanced
Balanced
Differential
Unbalanced
Balanced
Differential
Unbalanced
Balanced
Differential
Connect shield .
output
output
output
input
output
input
output
output
output
Balanced (in the above illustration) means transformer
balanced, while differential is electronically balanced.
There are some cases which met better results in practice.
Connect one circuit at a time and check for excess hum or
noise. When running any balanced microphones, use two
conductor shielded audio cables and connect both conductors
at both ends, and connect the shield at both ends. When
running line level cables, use two conductor shielded cable
and follow the instructions in the "General Audio
Installation" (section 8.0). The only exception to this rule
is patch cords, (these grounds are tied together in the
console). We know the proper interfacing of all the
different equipment is difficult, but once properly
installed the results will be clean and noise free. It is
important to understand the term "BALANCED" doesn't mean
the input or output is PROFESSIONAL. The single factor
that "usually" determines whether something is "pro" or not
is the level of the input or output (+4dBu is considered
professional and -lOdBv is considered semi-pro). Because
many semi-pro tape machines produce pro specs, D&R builds
into most console series the ability to interface with
both levels.
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