Specifications

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.