QSC CX-4-T Brochure

PRELIMINARY SPECIFICATIONS

CX4T

FEATURES

Toroidal Output Transformers—
Provide Full Electrical Isolation and
Meet Worldwide Safety Agency
Approval

Automatic T wo-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 and Power

Rear Panel Detented Gain Controls—
For Security and Resetability

Detachable Euro-Style Barrier Strip
Input—Easy and Economical
Connections

Double Thickness Rack Ears—For
Extra Strength

he CX4T 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 CX4T offers the features requested most
by contractors and installers from around the world.
The CX4T resides in a rugged two rack-space steel
chassis approximately 17.9 inches deep. With high
quality internal isolation transformers, the CX4T fea­tures built-in capability for driving 25, 70 or 100 volt
distributed sound systems as well as direct output
voice coil loads. Versatile design allows a 25, 70 or

LOAD OUTPUT POWER (Direct Outputs) OUTPUT POWER (Isolated Outputs)

45Hz-20kHz, 0.1% THD 1kHz, 1% THD 1 kHz, 0.1% THD

Stereo (W/Ch)

8Ω 150 watts 170 watts
4Ω 225 watts 250 watts
2Ω 350 watts*

25 volts 150 watts
70 volts 175 watts

100 volts 175 watts

Mono-Bridged

16Ω 300 watts 340 watts

8Ω 450 watts 500 watts
4Ω 700 watts*

50 volts 300 watts
140 volts 350 watts
200 volts 350 watts

100 volt connection on one channel and a direct
connection on the other channel. For maximum flex­ibility, you can even drive a distributed line and a
low impedance load on the same channel at the
same time! The CX4T features a built-in 50 Hz sub­sonic filter that reduces saturation of speaker trans­formers caused by excessively low frequencies. High
output power, versatile loading options, high ther­mal capacity and rugged reliability make the CX
amplifiers ideal for any high quality sound system
installation.

Covered Barrier Strip Output
Connections—Meets Safety Agency
Requirements

Simple Barrier Strip Connection
Determines Output Mode—25 V , 70 V ,
100 V and Direct Outputs Available
Simultaneously

Built-in 50 Hz Subsonic Filter—
Prevents Speaker Transformer
Saturation With Minimal Effect on
Program Material

1675 MacArthur Boulevard
Costa Mesa, California 92626-1468 USA
Phone: [phone] Fax: [phone]

*typical

POWER OUTPUT

Direct output, watts per channel, both channels driven

8Ω, 45 Hz-20 kHz, 0.1% THD 150
8Ω, 1 kHz, 1% THD 170
4Ω, 45 Hz-20 kHz, 0.1% THD 225
4Ω, 1 kHz, 1% THD 250
2Ω, 1 kHz, 1% THD* 350

Isolated outputs, watts per channel, both channels driven

70V or 100V, 1 kHz, 0.1% THD 175
25V, 1 kHz, 0.1% THD 150

Direct Outputs, bridged mono

8Ω, 45 Hz-20 kHz, 0.1% THD 450
4Ω, 1 kHz, 1% THD* 700

Isolated outputs, bridged mono

50V, 1 kHz, 0.1% THD 300
140V, 1 kHz, 0.1% THD 350
200V, 1 kHz, 0.1% THD 350

DISTORTION SMPTE-IM, less than 0.05%, direct outputs
FREQUENCY RESPONSE

Direct outputs: -3 dB @ 50 Hz*, -0.2 dB @ 20 kHz
Isolated outputs: 50 Hz*-16 kHz, +0, -3 dB

* Low frequency response is limited by 12 dB/octave 50-Hz high-pass filter.

DAMPING FACTOR 200 (@ direct outputs)
OUTPUT REGULATION 100V–1.0 dB; 70V–1.1 dB; 25V–2.0 dB
NOISE 100 dB below rated output (20 Hz to 20 kHz)
VOLTAGE GAIN

@ direct outputs 35x (31 dB)

INPUT SENSITIVITY, V

for rated power, 8Ω 0.96

INPUT IMPEDANCE 10K unbalanced, 20K balanced
CONTROLS

CX4T Specifications

Front: AC Switch
Rear: 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)

CLIP: Red 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
OUTPUT CIRCUIT TYPE Class AB complementary linear stage
POWER REQUIREMENTS: 100, 120, 220-240 VAC, 50/60 Hz

POWER CONSUMPTION

Normal operation: 1/8 power @ 4Ω per channel
Worst case continuous program: 1/3 power @ 2Ω per channel
Maximum: full power @ 2Ω per channel
Multiply current by 0.5 for 220-240 VAC operation

DIMENSIONS

Faceplate Width Standard 19" (48.3 cm) Rack Mounting
Chassis Depth 17.9" (45.5 cm) deep (to rear support ears)
Faceplate Height 3.5" (13.3 cm)

WEIGHT Shipping–46 lb; 21 kg; Net–40 lb; 18.2 kg

RMS

FPO/BACK

ARCHITECT’S AND ENGINEER’S SPECIFICATIONS

The amplifier shall contain all solid-state circuitry, using complementary
silicon output devices in a Class AB output circuit. The amplifier shall
operate from 50-60 Hz AC power, with internal taps for selecting voltages
100,120, or 220-240 VAC. The amplifier shall operate from a normal house­hold AC outlet, drawing less than 500 VA when driven 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
minimum acoustic noise. Air flow shall be from rear to front to avoid tem­perature rise inside the rack. Rack mounting shall be possible without
clearance necessary between amplifiers for ventilation. The amplifier shall
be capable of continuous operation at 1/8 power, into four -ohm loads, for
ambient temperatures up to 104 F (40 C).

The amplifier shall contain two independent channels, with separate AC
transformer secondaries, power supplies, and protection systems. All pro­tection systems shall be self resetting upon removal of fault, and the re­maining channel shall continue to operate. Each channel shall have inde­pendent protective circuitry against open circuit, short circuit, or mis­matched loads. Each channel shall monitor temperature of its heat sink
and shall trigger fan speed boost, and if necessary, signal muting to pre­vent excessive temperature rise. Each channel shall have on-off muting,
acting for three seconds after turn-on, and within 1/4 second after turn­off or loss of AC power. Each channel shall have DC fault protection for
the load. Fault fuses shall be adequately large to prevent nuisance blow­ing at any output power the amplifier is capable of delivering.

Each channel shall have the following controls and displays: A rear panel
Gain control and front panel displays consist of a green LED power-on
indicator and a red LED showing true amplifier clipping. The output con­nectors for each channel shall be shrouded barrier strip connectors. The
standard input panel shall provide detachable Euro-style header connec­tions for each channel. Inputs shall be electronically balanced, with a mini­mum impedance of 10 kilohms per side, and a common mode rejection of
at least 50 dB from 20 Hz to 20 kHz.

Internally-mounted toroidal output transformers shall provide electrically
isolated output taps for 25, 70, and 100 volt distributed lines. The direct
amplifier output shall also be available to drive voice coil loads. The use
of voice coil and distributed line operation is independent on each chan­nel. It is possible to use both the direct and isolated outputs simulta­neously on a single channel, as long as the total power rating of the am­plifier is not exceeded. A built-in 50 Hz, second-order subsonic filter shall
be provided to reduce saturation of speaker transformers, due to exces­sive low frequency program material. The filter is non-defeatable and af­fects all outputs.

Each channel shall be capable of meeting the following performance cri­teria with both channels driven: Sine-wave output power of 150 watts
into eight ohms, and 225 watts into four ohms, 50 Hz to 20 kHz, with less
than O.1% THD. Frequency response at 3 dB below rated power shall be ­3 dB at 50 Hz and -0.2 dB at 20 kHz. The voltage gain shall be 35, equiva­lent to 31 dB, and the input sensitivity shall be 0.96 V
noise ratio over the range of 20 Hz to 20 kHz shall exceed 100 dB. IHF
damping factor shall exceed 200 for the direct outputs. Output regulation,
of the isolated outputs, shall not exceed 1.0 dB at 100 volts, 1.1 dB at 70
volts and 2.0 dB at 25 volts.

The amplifier chassis shall occupy two 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 40 Ibs. (18.2 kg). The amplifier shall be the QSC
Audio Products Model CX4T.

. The signal to

RMS

1675 MacArthur Boulevard • Costa Mesa, California 92626-1468 USA • Phone: [phone] Fax: [phone]