QSC Audio CX Series - Manual (Page 30)

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AC CURRENT CONSUMPTION
A major objective in the design of the CX Series amplifiers—even the higher-powered models—is to permit
their operation from readily available, standard AC power sources.
“Normal conditions” in power amplifier rating means operating with a random program source (pink noise), using
pink noise as a source, at an average power level equal to one-eighth of maximum power. This is recognized by
most of the world’s safety agencies as the loudest you can play music through an amplifier and still keep the
incidence of clipping to a reasonable minimum. An amplifier’s peak current draw at full output power into 2 ohms
is several times what the “normal” draw is, but its various protection circuits will prevent this condition from
lasting more than a minute or two.
When you plan the AC power hookups for your amplifiers, use the following table to predict the current
requirements per ampli-
fier. You can use the one-
eighth power figures to
predict the normal continu-
ous current draw, then add
a safety margin to allow
for occasional crescendos.
HEAT EMISSIONS
Essentially, a power amplifier draws electrical energy from the AC mains, converts it to DC, and then converts
it again into an analog of the input signal to send out to the loudspeakers. Any AC power that enters the amplifier
through the power cord and does not exit through the speaker outputs turns into heat, which the amplifier must
rid itself of by exhausting it to the outside. In indoor use, multiple amplifiers may present a sizeable challenge
to a building’s air conditioning system. Use the table below to predict the heat that will be emitted by your
amplifier. Use one-eighth power for normal, continuous usage.
CX4, CX4T
CX6, CX6T
CX12, CX12T
0.4A 6.0A 2.8A 2.5A 10A 4.5A 3.8A 15A 6.8A 5.6A
0.9A 7.9A 4.3A 3.2A 13A 7.5A 5.0A 19A 10A 7.0A
1.0A 15A 8.6A 5.1A 24A 12A 6.5A 33A 17A 8.5A
AC Current Consumption
IDLE
8
Ω
FULL 1/3 1/8
POWER POWER POWER
4
Ω
or Distributed Line
FULL 1/3 1/8
POWER POWER POWER
2
Ω
FULL 1/3 1/8
POWER POWER POWER
Model
CX4, CX4T
CX6, CX6T
CX12, CX12T
110 490 765 1545
28 123 193 389
250 890 735 735 1630 1655 905 3145 2205 1655
63 224 185 185 411 417 228 793 556 417
265 1725 1530 945 3250 2395 1360 5545 3785 2230
67 435 386 238 819 604 343 1397 954 562
Heat Emissions
IDLE
(preliminary)
Btu/hr
kcal/hr
Btu/hr
kcal/hr
Btu/hr
kcal/hr
Model
8
Ω
FULL 1/3 1/8
POWER POWER POWER
4
Ω
or Distributed Line
FULL 1/3 1/8
POWER POWER POWER
2
Ω
FULL 1/3 1/8
POWER POWER POWER