Input Wiring; Speaker Wire; Remote Control Wire; Mechanical - Ashly FA Series Operating Manual

FA Amplifier • Operating Manual
2.2
Input Signal Wire Requirements
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/video emissions.
Unbalanced lines of less than 10 feet are
generally ok, but for greater distance or noisy
field environments, always use balanced signal
wiring.
If using an unbalanced input source, wire the
hot signal to the amplifier's (+) input Euroblock
pin, and connect the (-) input pin to ground. Do
not leave the (-) input pin 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 Speaker Wire Requirements
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 rms.
Speaker wire gauge: FA amplifiers are capable
of delivering high levels of output current, so
the wire gauge used for speaker outputs is
important. 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 Ohms 8Ω 4Ω
Gauge /100ft load load
#8 0.0605Ω 0.8% 1.5%
#10 0.1018Ω 1.3% 2.5%
#12 0.1619Ω 2.0% 4.0%
#14 0.2575Ω 3.2% 6.4%
#16 0.4094Ω 5.1% 10.2% 20.4%
#18 0.6510Ω 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
accurately 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 - Bell or telephone
wire is sufficient for DC level control to an
Ashly WR-1 or similar equivalent. CAT5
cable can also be used. The +3V and Gnd
pins can be shared among remote control
potentiometers, however do not connect
remote control ground to any external
grounds.
• Remote Standby - This is a logic level signal
which can use unshielded low gauge wire.
2.5

Mechanical

2Ω
FA-125.2 and FA-125.4 models use a 1RU
load
half-rack chassis. The FA-250.4 model uses a
3% 1RU full rack chassis. See the specifications for
dimensions.
5%
Hardware kits are available for purchase from
8%
Ashly for mounting half-rack models to a 19"
12.8% rack or table/wall surface, plus a rear support
kit is also available for all models.
• FA-TWB kit (sold separately): For mounting a
half-rack unit to a table or wall. Not available
for full-rack unit:
5