P83243 C
Sheet 3 of 6
8.
AUDIO OUT (SEE FIGURE 3):
Connect (2) output wires from the speaker load, to the COM screw terminal and the selected constant voltage terminal, (i.e. 25V, 70.7V or 100V).
The constant voltage distribution method facilitates the use of multiple speakers in parallel with a single amplifier. Note that each speaker must
have its own 25V, 70.7V or 100V line-matching transformer. Select the wattage tap on the line matching transformer of each speaker for the
power (volume) desired. An 8 Ohm speaker load may be connected to the COM and the 8 Ohm terminals. The audio output is available at the
rated output of 250 or 500 Watts for an 8 Ohm load, for a 25V, 70.7V or 100V. The GND terminal of the AUDIO OUT terminal block is chassis
ground. The shield of audio output shielded cable should be terminated to this GND (if applicable). The COM and GND of AUDIO OUT terminal
are connected to chassis ground.
Note
: The wattage rating of the speaker loads should not exceed total power rating of the amplifier. The following Table 2 below will provide the
appropriate line loss that should be calculated for those expected speaker loads.
CAUTION:
Do not operate amplifier without a proper load attached to audio out terminals.
CAUTION:
Do not connect, disconnect wiring or cabling with power applied.
9.
PROPER WIRE SIZE/LENGTH:
To minimize power loss in the system cabling, use a wire gauge suitable for the power being distributed and the length of cable. Use the following
table as a guide.
Table 2: 2 Wire Copper Cable Lengths for Speaker Lines at 0.5dB Loss in SPL
(12.5% Power Loss in Watts)
AWG
Max
Low Impedance
70 Volt Speaker Line
AWG
Size
Power
Speaker Line
Nominal Power in the Load Length in Feet
Size
AWG
8
Ohms
10W 15W 20W 40W 60W 100W 125W 200W 250W 400W 500W
10 Per
NEC
240
15,000 9,900 7,500 3,750 2,500 1,500 1,180 730 590 370 290 10
12
Per NEC
150
9,100
6,200
4,680
2,340
1,560
940
730
460
370
230
180
12
14
1,060W
95
5,600
3,800
2,880
1,440
960
600
450
280
220
140
110
14
16
420W
60
3,600
2,400
1,870
930
620
370
290
180
140
90
----
16
18
210W
40
2,300
1,500
1,150
570
380
230
180
110
----
----
----
18
20
70W
25
1,400
960
730
360
240
----
----
----
----
----
----
20
22
35W
15
900
600
460
----
----
----
----
----
----
----
----
22
Notes
:
1) For 25V line divide all 70.7V lengths by 8. 2) For 100V line multiply all 70.7V lengths by 2.0. 3) To allow for future expansion and distribution cable
line loss, it is recommended that the total system wattage should not exceed 85% of the amplifier’s rated output. (i.e. 212 and 425 Watts for the PA-250
and PA-500 respectively). 4) The total system wattage requirement is the summation of the wattage tap selections of all system speakers and horns.
Figure 3: Output Connections
WARNING: THE COVER FOR THE 100V AUDIO OUTPUT TERMINAL MUST BE ATTACHED AT ALL TIMES. THE POWER CORD MUST BE
DISCONNECTED BEFORE CONNECTING TO THE 100V TERMINAL. THE COVER MAY BE REMOVED TO CONNECT A WIRE TO THE
TERMINAL, BUT IT MUST BE REATTACHED AFTER CONNECTING THE WIRE(S). FAILURE TO MAINTAIN THE TERMINAL COVER IN PLACE
COULD EXPOSE YOU AND/OR OTHERS TO ELECTRICAL SHOCK WHICH COULD RESULT IN SERIOUS INJURY AND/OR DEATH.
10. CASCADING AMPLIFIERS (SEE FIGURE 4):
The BOOSTER OUT of the PA-250 or PA-500 amplifier, which is the buffered LINE IN audio signal, can be used as a LINE IN input to additional
PA-250’s or PA-500’s to expand existing systems or to distribute large speaker loads.
