GAI-Tronics 69037-101 Centra-Page Station Card - Manual (Page 4)

Pub. 42004-221A
Model 69037-101 Station Card for Centra-Page Systems Page: 4 of 4
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Speakers
8-Ohm Out Operation
When using the 8-ohm output connections, always use speakers of proper voice coil impedance and
power handing capability. Consult GAI-Tronics Pub. 42004-135 and 42004-220 for more details on
speaker installation and wiring.
70.7 Volt Out Operation
Greater speaker line distances from the central cabinet can be obtained by using the 70.7 V output
connection compared with using 8-ohm output. The individual speaker’s power level is determined by
the tap settings on the line-matching transformer. The use of these transformers allows the speakers to be
placed at longer distances from the central amplifier system without significant power loss.
The sum of the speaker power settings must not exceed the total power available from the amplifier
PCBA. For example, the 69037-101 PCBA’s 70.7 V output (~16 W out with ~27 V dc in) can drive
approximately eight speakers tapped at 2 watts each or four speakers tapped at 4 watts each.
Speaker Wiring Distance Guide
Cable distance should be kept as short as possible to reduce the power loss. The following chart
illustrates the correlation between three typical wire sizes and the distance that speakers with integral
drivers or horns with separate drivers can be placed from the central card rack for a –1 dB loss (-20%
power loss). For a 0.5 dB loss, divide all lengths in half.
Table 1.
Speaker Wiring Guidelines for 69037-101 PCBA Based on ~27 V DC Input to Card
Rack Assembly
Wire Size Speaker Output
Connection
18 AWG (0.82 mm2) 16 AWG (1.31 mm2) 14 AWG (2.08 mm2)
8-Ohm Out 77 feet (23.5 meters) 123 feet (37.5 meters) 196 feet (59.7 meters)
70.7 Volt Out 2,900 feet (884 meters) 4,700 feet (1,432 meters) 7,500 feet (2,286 meters)