Input Connection; Unbalanced Input Wiring; Balanced Input Wiring; Balanced And Unbalanced Phone Plugs - Crown Macro-Tech MA-1200 Reference Manual

3.3.4 Input Connection

Both the balanced XLR and phone jack inputs have a
nominal impedance of 20 k ohms (10 k ohms with un-
balanced wiring) and will accept the line-level output of
most devices. Female three-pin XLR input connectors
are provided on the standard P.I.P.- FX input module
(other PIP modules are described in Section 8.1). Cor-
rect input wiring will depend on two factors: (1) whether
the input signals are balanced or unbalanced, and (2)
whether the signal source floats or has a ground refer-
ence. Figures 3.7 and 3.8 show the recommended con-
nection techniques for each type of signal source.
The amplifier's built-in ¼-inch phone jack input connec-
tors can be wired similarly for balanced or unbalanced,
floating or ground-referenced sources. They have a
Fig. 3.7 Unbalanced Input Wiring
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Macro-Tech 600/1200/2400 Power Amplifiers
Fig. 3.8 Balanced Input Wiring
standard tip-ring-sleeve (TRS) configuration: the tip is
positive (+), the ring is negative (–) and the sleeve is
ground (see Figure 3.9). Wiring for various sources fol-
lows the XLR wiring guidelines shown in Figures 3.7
and 3.8.
The phone jacks should not be used as inputs when a
PIP module with active circuitry is installed. The phone
jacks are in parallel with the output of the PIP module,
so an input signal connected to the phone jacks can
feed backwards into the active circuitry of the PIP and
cause undesirable distortion. You can use the phone
jacks for signal input with any of the following PIP mod-
ules installed: P.I.P.-FX, P.I.P.-BB, P.I.P.-FMX, P.I.P.- FXQ
and P.I.P.-FPX. All other PIP modules have active cir-
cuitry and should not be installed if you plan to connect
input signals to the phone jacks. The phone jacks can
always be used as "daisy chain" outputs to feed post-
processed signals from the PIP to the inputs of other
amplifiers.
Please follow the instruction in Section 3.3.2 and 3.3.3 if
the amplifier will be used in either Bridge-Mono or Par-
allel-Mono mode. Remember, do not use the Channel 2
input in either of these mono modes.
Fig. 3.9 Balanced and Unbalanced Phone Plugs
Reference Manual