Crown Micro-Tech 1201 - 3.3.4 Input Connection Methods

Page 14
Micro-Tech 600/1200/2400 Power Amplifiers
3.3.4 Input Connection
The balanced phone jack inputs have a nominal im-
pedance of 20 K ohms (10 K ohms with unbalanced
wiring) and will accept the line-level output of most de-
vices. Three-pin female XLR connectors are also avail-
able on the optional MT-XLR accessory and balanced
barrier block connectors are available on the optional
MT-BB accessory (see Section 8.2). Correct input wir-
ing 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 reference. Fig-
ures 3.7 and 3.8 provide examples of recommended
connection techniques for each type of signal source.
The optional MT-XLR connector is shown.
Fig. 3.7 Unbalanced Input Wiring
for the Optional MT-XLR
Twin-lead shielded cable
2-wire line cord
(or battery power)
Shield connected
to ground terminal
3-wire grounded line cord
(or other ground connection)
Shield is not
connected
at this end
Grounded
source
3-wire grounded line cord
(or other ground connection)
Input ground
terminal not used
Grounded
source
Single-conductor coax
or twisted pair
2-wire line cord
(or battery power)
Floating
source
Shield connected to both
negative (–) and ground
input terminals
+
–
INPUT
Output
Floating
source
+
3
1 2
+
–
INPUT
+
Output
3
1 2
+
–
INPUT
Output
+
3
1 2
+
–
+
Output
INPUT
3
1 2
3
1 2
+
–
INPUT
2-wire line cord
(or battery power)
Note: If two or more channels with
the same input ground reference
are driven from the same
floating source, connect
only one shield to the
source chassis.
Floating
source
3-wire grounded line cord
(or other ground connection)
Shield not connected
at this end
Grounded
source
3
1 2
Output
+
–
+
–
Output
+
–
INPUT
Fig. 3.8 Balanced Input Wiring
for the Optional MT-XLR
The amplifier’s built-in
1
¦4-inch input phone connectors
can be wired similarly for balanced or unbalanced,
floating or ground-referenced sources. The phone con-
nectors have a standard tip-ring-sleeve (TRS) configu-
ration: the tip is positive (+), ring is negative (–) and
sleeve is ground (see Figure 3.9). Wiring for different
sources follows the XLR wiring guidelines shown in Fig-
ures 3.7 and 3.8.
When either of the input connector accessories is in-
stalled, the unused input connectors can be used as
“daisy chain” outputs to feed the input signal from one
amplifier to another.
Please follow the input wiring instructions in Section
3.3.2 and 3.3.3 if the amplifier will be used in either
Bridge-Mono or Parallel-Mono mode. Remember, do
not use the channel 2 input in either mono mode.
Fig. 3.9 Balanced and Unbalanced
Phone Plug Wiring
+
–
SHIELD
BALANCED
+
SHIELD
UNBALANCED