PS Engineering
PAC45 Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-045-0100
Page 2-4
January 2020
insulated washers to isolate the ground return path from the airframe to
all
headphone and mi-
crophone jacks.
2.4.1.1 Music Input and Noise
PAC45D units utilize a differential ground input to help prevent noise from entering the audio
system. This feature is usually transparent to the installer; however, it is important that the ap-
propriate music signal and ground connections are made directly to the dedicated music signal
and ground inputs on the PAC45D. The power for IFE and audio controller should be a common
bus.
NOISE NOTE
Adding a high-performance audio control system, particularly in conjunction with high-perfor-
mance active noise canceling headsets, cannot improve on older avionics that were designed for
cabin-speaker use. PS Engineering makes no claim that the audio controller will provide a noise-
free audio quality under all installation conditions, particularly with older avionics.
2.4.2 Power
The PAC45D is compatible with 28 Volt DC systems. A one (1) Amp circuit breaker is required for
all installations. Power and ground wires should be #22AWG connect power to P451 Pin 17.
Connect airframe ground to P451 Pin 34 only.
Power consumption is as follows:
At 28V:
•
Hub + Control Head: 500 mA
•
Control head Only: 150 mA
•
Hub Only: 350 mA
•
Alert audio power: 10mA
At minimum input voltage (18V):
•
Hub + Control Head: 750mA
•
Control head Only: 200mA
•
Hub Only: 500mA
Lighting input: <5mA
CAUTION: Do not connect or disconnect (
HOT SWAP
) any components with power applied, this
will damage the units
2.4.2.1 Alert power, P451 Pin 16,
The PAC45D has an independent alert system with the ability to play alerts even when the audio
controller is powered off. To take full advantage of this isolation a separate one (1) Amp circuit
breaker is required. Power should be #22AWG connect power to P451 Pin 16.
When power to P451-16 is present, the message will play three times or until the remote
acknowledge is selected.
2.4.3 Audio controller interface
The PAC45D is designed to interface with standard aircraft avionics, and presents a 510
re-
ceiver impedance. For best results, a twisted-shielded cable is recommended from the avionics
audio source to the audio controller, with the shield grounded at the audio controller end.
Some avionics do not provide a separate audio low, and may introduce additional electrical
noise into the system. For best results, connect the audio low from the audio controller to the
radio ground, using one conductor of the twisted-shielded cable.
PRELIMINARY
