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 | |
8Ω 20 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, 8Ω | 1.00 | |
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 @ 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
Channel Load AC Current, Full Power | AC Current, 1/3 Power | AC Current, 1/8 Power | AC Current, Idle |
8Ω + 8Ω | 14.7 A | 8.4 A | 4.5 A | 0.8 A |
4Ω + 4Ω | 23 A | 12.4 A | 6.1 A | 0.8 A |
2Ω + 2Ω | 33 A | 16.5 A | 8.0 A | 0.8 A |
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- dinary class-B linear output circuit. Overall electrical efficiency, with four or eight-ohm loads, shall exceed 40% at 1/3 power and 30% at 1/8 power. 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 750 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 tem- perature 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 pro- tection systems shall be self resetting upon removal of fault, and the re- maining channel shall continue 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 shall have on-off muting, acting for three seconds after turn-on, and within 1/4 second after turn-off or loss of AC power. Each channel shall have DC fault protection for the load, consisting of a load-grounding relay with fault fusing to interrupt power. 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 Bridge/Stereo/Parallel mode switch, front panel displays 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 red LED which indicates muting when illuminated. The output connectors for each channel shall be shrouded barrier strip connectors. The input connector shall be mounted on a removable panel to permit upgrades. The standard input panel shall provide detachable Euro-style header con- nections for each channel. Inputs shall be electronically balanced, with a minimum impedance of 10 kilohms per side, and a common mode rejec- tion of at least 50 dB from 20 Hz to 20 kHz. The standard input panel shall 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 board measuring up to 5.9" wide by 4.1 “ deep. The multi-pin connector to 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 installed in place of a standard blank 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 into eight ohms, and 600 watts into 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 the input sensitivity shall be 1.00 Vrms. The signal to noise ratio over the 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.
