QSC CX12 User manual

CX12
FEATURES
1675 MacArthur Boulevard
Costa Mesa, California 92626-1468 USA
Phone: [phone] Fax: [phone]
CX Series
Automatic Two-Speed, High
Efficiency Fan Cooling—For Quiet
Normal Operation with Maximum
Cooling on Demand
Rear-to-Front Air Flow—Keeps
Equipment Racks Cool
Front Panel Status LED’s—Indicate
Clip, Protect, Power and Signal
Presence
RearPanelDetentedGainControls—
For Security and Resetability
Open Input Architecture™—Flexible
Input Options
Detachable Euro-Style Barrier Strip
Input—Easy and Economical
Connections
Stereo,Bridge,orParallelOperating
Modes—Switch Selectable
Double Thickness Rack Ears—For
Extra Strength
Covered Barrier Strip Output
Connections—Meets Safety Agency
Requirements
he CX12 amplifier is ideal for use in any
permanently installed sound system.
Designed to meet the specialized needs
of high power, high quality audio systems,
the CX12 offers the features requested
most by contractors and installers from
around the world. Rear panel gain
controls offer extra security and front
panel status LEDs offer easy indication of
the amplifier conditions. Per channel
power ratings of 400 watts at 8 ohms,
LOAD OUTPUT POWER
20Hz-20kHz, 0.1% THD 1kHz, 1% THD
Stereo (W/Ch)
8Ω400 watts 475 watts
4Ω600 watts 700 watts
2Ω900 watts*
Mono-Bridged
16Ω800 watts 950 watts
8Ω1200 watts 1400 watts
4Ω1800 watts*
*typical
600 watts at 4 ohms and 900 watts at 2
ohms make the CX12 an economical
choice for direct output applications that
don't require the output transformers of
the CX 12T. The CX12 resides in a rugged
three rack-space steel chassis approxi-
mately 17.9 inches deep. High output
power, high thermal capacity and rugged
reliability make the CX amplifiers ideal for
any high performance sound system
installation.

FPO/BACK
CX12Specifications
POWER OUTPUT
Direct output, watts per channel, both channels driven
8Ω, 20 Hz-20 kHz, 0.1% THD 400
8Ω, 1 kHz, 1% THD 475
4Ω, 20 Hz-20 kHz, 0.1% THD 600
4Ω, 1 kHz, 1% THD 700
2Ω, 1 kHz, 1% THD* 900
Direct Outputs, bridged mono
8Ω20 Hz-20 kHz, 0.1% THD 1200
4Ω, 1 kHz, 1% THD* 1800
*typical
DISTORTION SMPTE-IM, less than 0.05%
FREQUENCY RESPONSE 20 Hz-20 kHz, ±0.2 dB
DAMPING FACTOR 200
NOISE 100 dB below rated output (20 Hz to 20 kHz)
VOLTAGE GAIN 56.5x (35 dB)
INPUT SENSITIVITY, VRMS
for rated power, 8Ω1.00
INPUT IMPEDANCE 10K unbalanced, 20K balanced
CONTROLS
Front: AC Switch
Rear: Parallel/Stereo/Bridge Switch,
Ch.1 and Ch. 2 Attenuator Knobs (11 detents: 0, -2, -4, -6, -8, -10, -12, -14, -18, -24, off)
FRONT PANEL/INDICATORS (per channel)
PROTECT: Red LED
CLIP: Red LED
SIGNAL: Yellow LED
POWER: Green LED
REAR PANEL/CONNECTORS (each channel)
Input: Euro-style detachable header
Output: Covered barrier strips
COOLING 2-speed fan, with back-to-front air flow
AMPLIFIER PROTECTION
Output Averaging™ short circuit protection, open circuit, ultrasonic, RF, thermal muting
Stable into reactive or mismatched loads
LOAD PROTECTION Turn-on/turn-off muting, DC-fault load grounding relay with internal fault fuses
OUTPUT CIRCUIT TYPE Class H complementary linear stage, with 2-step high-efficiency circuit
POWER REQUIREMENTS: 100, 120, 220-240 VAC, 50/60 Hz
POWER CONSUMPTION
Normal operation: 1/8 power @ 4Ωper channel
Worst case continuous program: 1/3 power @ 2Ωper channel
Maximum: full power @ 2Ωper channel
Multiply current by 0.5 for 220-240 VAC operation
Channel Load AC Current, Full Power AC Current, 1/3 Power AC Current, 1/8 Power AC Current, Idle
8Ω+8Ω14.7A 8.4A 4.5A 0.8A
4Ω+4Ω23A 12.4 A 6.1A 0.8A
2Ω+2Ω33A 16.5 A 8.0A 0.8A
DIMENSIONS
Faceplate Width Standard 19" (48.3 cm) Rack Mounting
Chassis Depth 17.9" (45.5 cm) deep (to rear support ears)
Faceplate Height 5.25" (13.3 cm)
WEIGHT Shipping–58 lb; 26.3 kg; Net–50 lb; 22.7 kg
ARCHITECT’S AND ENGINEER’S SPECIFICATIONS
The amplifier shall contain all solid-state circuitry, using complementary
silicon output devices. The amplifier shall exceed the efficiency of an or-
dinaryclass-Blinearoutputcircuit.Overallelectricalefficiency,withfour
oreight-ohmloads,shallexceed40%at1/3powerand30%at1/8power.
Theamplifiershalloperatefrom50-60HzACpower,withinternaltapsfor
selecting voltages 100,120, or 220-240 VAC. The amplifier shall operate
fromanormalhouseholdACoutlet,drawinglessthan750VAwhendriven
with random program material at 1/8 rated power into four ohm loads.
The amplifier shall be supplied with a single molded AC cord having an
appropriate AC plug for the intended operating voltage.
The amplifier shall employ forced-air cooling with a two speed fan for
minimumacoustic noise.Air flowshallbe fromrear tofrontto avoidtem-
perature rise inside the rack. Rack mounting shall be possible without
clearancenecessarybetweenamplifiersforventilation.Theamplifiershall
becapable of continuousoperationat 1/8power,intofour-ohmloads, for
ambient temperatures up to 104 F (40 C).
The amplifier shall contain two independent channels, with separate AC
transformersecondaries,powersupplies,andprotectionsystems.Allpro-
tection systems shall be self resetting upon removal of fault, and the re-
mainingchannelshallcontinue to operate. Each channel shall have inde-
pendent protective circuitry against open circuit, short circuit, or mis-
matched loads. Each channel shall monitor temperature of its heat sink
and power transformer, and shall trigger fan speed boost, and if neces-
sary, signal muting to prevent excessive temperature rise. Each channel
shallhaveon-offmuting,actingforthreesecondsafterturn-on,andwithin
1/4second afterturn-offor lossofAC power.Eachchannelshall haveDC
fault protection for the load, consisting of a load-grounding relay with
fault fusing to interrupt power. Fault fuses shall be adequately large to
preventnuisance blowing atanyoutput powertheamplifier is capableof
delivering.
Eachchannelshall have the followingcontrolsand displays: A rear panel
GaincontrolandBridge/Stereo/Parallelmodeswitch,frontpaneldisplays
consist of a green LED power-on indicator; one yellow LED signal indica-
tor, triggering at -30 dB; a red LED showing true amplifier clipping; and a
redLEDwhichindicatesmutingwhenilluminated. Theoutputconnectors
for each channel shall be shrouded barrier strip connectors. The input
connector shall be mounted on a removable panel to permit upgrades.
Thestandard input panelshallprovide detachable Euro-styleheadercon-
nectionsforeach channel. Inputs shall be electronically balanced, with a
minimum impedance of 10 kilohms per side, and a common mode rejec-
tionof atleast50 dBfrom20 Hzto20 kHz.Thestandard inputpanelshall
contain switches for mono-bridging and parallel inputs, and solder pat-
terns for input isolation transformers, gain reduction resistors, and first-
order high and low pass filters .
The input panel shall have enough space behind it to contain a circuit
boardmeasuringup to5.9"wideby4.1“deep.Themulti-pinconnectorto
the amplifier circuitry shall supply positive and negative DC supply cur-
rents, and for each channel, balanced input signals, output signal, and
clip/protect signal. Optional XLR and 1/4” RTS input connectors may be
installedinplaceofastandardblank panel, mounted above the standard
input panel.
Each channel shall be capable of meeting the following performance cri-
teria with both channels driven: Sine-wave output power of 400 watts
intoeightohms,and600wattsinto four ohms, 20 Hz to 20 kHz, with less
than O.1% THD. Frequency response at 3 dB below rated power shall be
within ±0.2 dB. The voltage gain shall be 56.5, equivalent to 35 dB, and
theinputsensitivity shall be 1.00 Vrms.The signal to noise ratiooverthe
range of 20 Hz to 20 kHz shall exceed 100 dB. IHF damping factor shall
exceed 200.
The amplifier chassis shall occupy three rack spaces, with provision for
securing the rear corners. Depth from mounting surface to tips of rear
supports shall be 17.9" (45.5 cm).
Weight shall not exceed 50 Ibs. (22.7 kg). The amplifier shall be the QSC
Audio Products Model CX12.
1675 MacArthur Boulevard • Costa Mesa, California 92626-1468 USA • Phone: [phone] Fax: [phone]