Operating Manual - nX, nXe, and nXp Power Amplifiers
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2.2 Input Signal Wiring
Use shielded wiring for balanced or unbalanced audio signals. Shielding which is properly grounded will protect the signal from
outside electrical interference such as RF, fluorescent lighting, and computer/display emissions. Unbalanced or single-ended (tip-
sleeve) lines of less than 10 feet are generally ok, but for greater distance or noisy field environments,
always
use balanced signal.
Each channel's Euroblock, 1/4" phone jack, and XLR inputs are wired in parallel, with XLR pin 2 (+) and pin 3 (-). When using an
unbalanced input, wire the hot signal to the input (+) euroblock pin, phone jack tip, or XLR pin 2, and also be sure to wire the input
(-) pin, phone jack ring, or XLR pin 3 to ground.
Do not leave the (-) input unconnected.
Avoid running low level signal wires in
close proximity or parallel to long speaker cables, AC power cables, or power transformers, as they can induce hum or oscillation.
2.3 Output Speaker Wire
Note: The sound system installer is responsible for using loudspeaker wiring that is in compliance with local
electrical code.
The following recommendations for speaker wiring are based on UL 60065 section 5.2-d and the US National
Electrical Code Article 725. These are only guidelines, consult your local code for specific up to date requirements.
Class 2 wiring
is typically used
when the maximum measured open-circuit speaker output voltage is less than 120V r.m.s.
Class 3 wiring
is typically used if the measured open circuit output voltage exceeds 120V r.m.s, such as when 70V, 100V, or low-Z amplifiers are used
for specific model configurations that may require Class 3 speaker wiring.
Output Speaker Connectors:
nX amplifier speaker outputs use Neutrik SpeakON connectors because they are safe, secure, reliable,
and fully enclose any hazardous voltage.
Wire guage:
nX amplifiers are capable of delivering high levels of output current, so the wire gauge used for speaker outputs is im
-
portant. Inadequate wire gauge, especially over long distance, adds significant resistance to the speaker’s own impedance, reducing
the power which is actually delivered to the speaker. It could also result in a decreased damping factor and potential fire hazard. Since
power at the speaker load is of primary concern in system design, refer to the table below to best determine appropriate wire gauge for
your application. The following table lists the resistance per 100 feet of common copper wire gauges, and also lists the percentage of
the speaker load power which would be lost as heat in an arbitrary 100 ft run of different gauges of 2-conductor copper speaker wire.
Wire gauge resistance/power loss for 100ft speaker cable
Wire Gauge
Ohms/100ft
8 Ohm load
4 Ohm load
2 Ohm load
#8
0.0605 Ohms
0.8%
1.5%
3%
#10
0.1018 Ohms
1.3%
2.5%
5%
#12
0.1619 Ohms
2.0%
4.0%
8%
#14
0.2575 Ohms
3.2%
6.4%
12.8%
#16
0.4094 Ohms
5.1%
10.2%
20.4%
#18
0.6510 Ohms
8.1%
16.3%
32.6%
This table expresses the power loss as a percentage of the load’s power rather than the total amplifier output power in order to ac
-
curately determine power loss at other cable lengths. For example, if you plan to deliver 150 watts to an 8 Ohm load through 50 ft of
14 ga. cable, the power loss in the cable would be half that of a 100 ft run of #14 wire as shown in the table, or 1.6% of 150W, which
is an insignificant 2.4 watts. However, if you were to run 200 ft of 18 ga. cable to a 2 Ohm load, the loss would be twice that of the
100 ft run shown in the table, or 65.2% of 250W, which is 163 watts lost as heat. Always be sure to use adequate gauge speaker wire.
2.4 Remote Control Wire
Remote DC level control (all models)
- Unshielded bell or telephone wire is sufficient for DC level control, as is CAT5 cable.
The V+ and GND pins from one amplifier channel
can
be shared with other remote DC level controls wired to the same ampli
-
fier, however
do not connect this ground to any external grounds.
Remote Standby (nXe and nXp only)
- This is a logic level signal, use unshielded low gauge wire.
Fault (nXe and nXp only)
- This is also a logic level signal, unshielded low gauge wire is adequate.
Preset (nXe and nXp only)
- This is also a logic level signal, unshielded low gauge wire is adequate.
Data (nXe and nXp only)
- Four conductor telephone wire is suitable, as well as CAT5, but if shielded wiring is used be sure
to ground the source end of the shield.
Under no circumstances should shielding be left unconnected to ground, as the added
line capacitance will degrade the data signal.
Maximum data cable distance is 1,000 ft (305m).
