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Figure A
From
Channel 1
+ GND
(Shield)
From
Channel 2
+
GND
(Shield)
From
Channel 1
–+ GND
(Shield)
From
Channel 2
–+
GND
(Shield)
From
Channel 1
From
Channel 2
–+
GND
(Shield)
TIP
+
SLEEVE
(Shield)
From
Channel 2
TIP
+
SLEEVE
(Shield)
From
Channel 1
From
Channel 1
From
Channel 2
+
GND
(Shield)
Figure B Figure C
Figure D Figure E Figure F
For balanced operation:
1/4 inch phone plug: Use a 3-conductor TRS (tip-ring-sleeve) 1/4" phone plug. The tip of the plug carries the "+"
(high, non-inverting) side of the signal, the ring carries the "-" (low, inverting) side of the signal and the sleeve is
ground (see Figure A).
XLR: Use a male XLR connector. Pin 2 carries the "+" (non-inverting) side of the signal, Pin 3 carries the "-" (low,
inverting) side of the signal, and Pin 1 is ground (see Figure B).
For unbalanced operation:
1/4" phone plug: Use a 2-conductor (tip-sleeve) 1/4" phone plug. The tip of the plug carries the signal and the
sleeve is the ground. The sleeve (see Figure C) automatically grounds the ring connection in the jack.
XLR: Pin 2 carries the signal, and Pin 1 is ground. Short Pin 3 to Pin 1 in order to reference the input differential amplifier for
the correct gain (see Figure D).
BR Version
For balanced operation:
Use shielded twisted pair balanced line type cable with crimp-on or solder type 8mm spade terminals. For either channel
connect the "+" (high, non-inverting) side of the signal to the terminal labeled "+" on the Barrier Strip. Connect the "-" (low,
inverting) side of the signal to the terminal labeled "-" on the Barrier Strip. Connect the shield to the "ground" terminal (see
Figure E).
NOTE: Confirm which wires are "+" and "-" from the source unit. Refer to the 1/4" plug and XLR instructions for proper
configuration if these plugs are used at the source unit.
For unbalanced operation:
Use shielded single conductor coax type cable or twisted pair balanced line type cable with crimp-on or solder type spade
terminals. Connect the hot side of the signal to the terminal labeled "+" on the Barrier Strip. Connect the shield to "ground" and
connect a jumper wire between "ground" and the (-) terminal (see Figure F).
High Pass Filter
This filter will remove unwanted low frequency components from the input signal when engaged. It is engaged or disabled from
the Dip Switch located on the rear panel of the amplifier. The High Pass Filter is switched independently for each channel at
position #1 for CH2 and position #5 for CH1. The High Pass Filter is set at the factory to its disabled position.
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Installation
Location and General Precautions
Observe the following precautions when choosing a location for your amplifier.
A. Do not expose the unit to rain or moisture. If a fluid or foreign object should enter the unit, disconnect the power
plug and contact an authorized dealer or service center. Do not pull the plug by pulling on the cord; grasp the plug
firmly.
B. Protect from heat and allow adequate ventilation. Place away from direct sources of heat, such as heating vents and
radiators. All components produce some heat during operation, so make sure that the ventilation slots are not covered
and that air is allowed to circulate freely behind and above the unit. Excessive heat is the single greatest source of premature
component failure.
Mechanical Considerations
The PXm250 and PXm450 require two rack space units (3.5") and the PXm900 three rack space units (5.25"). All three have a
depth of 15.38" inside the rack, including the rear supports. Secure the unit mechanically using four screws with washers to prevent
marring the front panel. Neoprene rubber washers are a good choice because they grip the screw head and prevent them from
backing out when vibrated or transported.
Rear Support for Road Applications
If the PXm amplifiers are rack mounted, and the rack is transported, mechanical support for the rear of the amplifiers is required.
This could take the form of a shelf across the rear of the rack or brackets that engage the rear of the unit.
Thermal Considerations
When PXm amplifiers are used freestanding, no thermal considerations are necessary other than keeping the ventilation slots open.
If the amplifiers are rack-mounted, ensure that adequate ventilation exists in front of, behind and to the sides of the amplifier.
When several amplifiers are mounted together in a rack, you may need to provide air inlets from the outside of the rack. The PXm
amplifiers are fan cooled. The fan is internally mounted so that it draws air from the back and left side, and exhausts it out the
front. The PXm amplifiers may be stacked directly on top of each other without spacer panels. If the amplifiers are used with
other amplifiers, ensure that the heat output from the other amplifiers doesn't interfere with the ventilation of the PXm amplifier
(or vice versa).
AC Power Considerations
Ensure that the PXm amplifier is plugged into an outlet capable of supplying the correct voltage specified for your model and
enough current to allow full-power operation of all amplifiers plugged into it. The current demand of a power amplifier varies
depending on several factors, including the impedance of the load, the output level of the amplifier, and the crest factor and duty
cycle of the program material. Under typical conditions reproducing rock music, with both channels driven into 4 ohms to the
point where musical peaks are just at the clipping point, the amplifiers require the following average currents:
PXm250: 1.8A for 120V versions, .94Afor 230V versions
PXm450: 2.5A for 120V versions, 1.3A for 230V versions
PXm900: 5A for 120V versions, 2.6A for 230V versions
Magnetic Leakage Considerations
The PXm amplifiers may be mounted without concern for magnetic flux leakage, within the confines of common sense. For
example, it's not a good idea to mount any power amplifier near a microphone input transformer or magnetic storage media.
Input Wiring
(See page 18 for recommended Carver Professional Accessories)
Standard Version
The 1/4" TRS input connectors will accept either unbalanced 1/4" phone plugs or balanced 1/4" TRS phone plugs. The female
XLR will accept a male XLR connector. The input signal can be used with either unbalanced shielded single conductor or
balanced shielded 2 conductor cables. Use shielded coaxial cable to conduct the signal from the source (i.e. mixer, equalizer,
CD player) to the amplifier.
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