Page 2 - Table of Contents; PART 1—CX SERIES USER MANUAL; Open Input Architecture
1 Table of Contents PART 1—CX SERIES USER MANUAL I. Warning Notices ....................................................................................................................................... 2 Speaker Damage ..................................................................................
Page 3 - CAUTION; AVIS; VORSICHT; S A F E G U A R D S; DECLARATION OF CONFORMITY; for all CX and CXT models
2 EXPLANATION OF GRAPHICALS Y M B O L S The lightning flash with arrowheadsymbol, within an equilateral triangle,is intended to alert the user to thepresence of uninsulated “dangerousvoltage” within the product’s enclo-sure that may be of sufficient magni-tude to constitute a risk of electricshock t...
Page 4 - SPEAKER DAMAGE; output power if the input signal level is high enough.; SPEAKER OUTPUT SHOCK HAZARD
3 I. Warning Notices SPEAKER DAMAGE The CX Series amplifiers are among the most powerful professional amplifiers available and are capable of producing much more power than many loudspeakers can handle. It is the user’s responsibility to use suitable speakers with the amplifier and to use them in a ...
Page 5 - II. Overall Description; high. The adjacent table lists the amplifiers’ weights by model.; MODEL
4 II. Overall Description The CX Series from QSC comprises six high-efficiency professional power amplifier models, each with two independent channels. The table below lists the range’s audio power ratings. Each channel has its own power transformer secondary. The CX4, CX4T, CX6 and CX6T utilize com...
Page 7 - caused by a floating input.; INPUT SENSITIVITIES; additional important instructions.
6 Channel 2+ Channel 2- Ground Ground Ground Channel 1- Channel 1+ Loosen screw, insert wire here, then tighten screw. III. Inputs CX amplifiers feature balanced inputs, connected via a Euro-style 7-terminal detachable header. Attach input signal wires as shown. If you are connecting an unbalanced s...
Page 10 - “PROTECT” indicators lit until the power supplies are discharged.; TROUBLESHOOTING; Problem: Channel will not come out of muting; example) that could otherwise damage your speakers.
9 CX6, CX6T, CX12 and CX12T When the amplifier is first turned on, the red “PROTECT” LED on each channel will light for about two or three seconds, during which the output relays will stay open to mute the speakers. After the turn-on muting interval, the “PROTECT” LEDs turn off, the green “POWER” LE...
Page 11 - the cool-down and prevent repeated thermal shutdowns.; PROBLEM: Hum in the audio; OPEN INPUT ARCHITECTURE
10 • If the fan is not running at full speed, or the channel does not reset to normal after a cool-down period, the muting is probably because of a DC fault or other amplifier failure, especially if the “SIGNAL” or “CLIP” indicators are lit even with the attenuator turned all the way down. PROBLEM: ...
Page 13 - Instructions for bridged operation; Set the switch to the “Bridge” position.
12 Instructions for bridged operation CX4 and CX4T 1. To engage the bridged mono mode, jumper the barrier strip inputs on the rear, in accordance with the diagram printed under the barrier strip inputs. Connect the amplifier input to channel 1 only, with the jumpers as shown to channel 2. Channel 1 ...
Page 14 - MAXIMUM LONG-TERM OUTPUT POWER; the lower the load impedance, the more stressful the load is.; AC CURRENT CONSUMPTION; operation from readily available, standard AC power sources.
13 MAXIMUM LONG-TERM OUTPUT POWER In a properly designed sound system, you can obtain the desired sound level without using the full output power of the amplifier; if the “CLIP” indicators flash once in a while, that is perfectly normal. If the amplifier is operated at extremely high power levels, i...
Page 15 - HEAT EMISSIONS; Full Power
14 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 sp...
Page 16 - PROTECTION CIRCUITS; series takes a comprehensive approach to protection.
15 PROTECTION CIRCUITS The design goal in high-efficiency amplifiers such as the CX Series is to increase the amplifier’s ability to deliver peak power without increasing its size, weight, and cost. However, the higher power flow through the output components makes effective, responsive protection c...
Page 17 - DISTORTION; DAMPING FACTOR
16 VII. Specifications CX4 CX4T CX6 CX6T CX12 CX12T POWER OUTPUT Direct output, watts per channel,both channels driven 8 Ω , 20 Hz–20 kHz, 0.1% THD 150 200 400 8 Ω , 45 Hz–20 kHz, 0.1% THD** 150 200 400 8 Ω , 1 kHz, 1% THD 170 170 220 220 475 475 4 Ω , 20 Hz–20 kHz, 0.1% THD 225 300 600 4 Ω , 45 Hz–...
Page 19 - POWER CONSUMPTION; DIMENSIONS
18 VII. Specifications (cont.) POWER CONSUMPTION (see chart on page 13) Normal operation: 1/8 power @ 4 Ω per channel Worst case continuous program: 1/3 power @ 2 Ω per channel Maximum: full power @ 2 Ω per channel Multiply current times 0.5 for 220-240 VAC operation Model Channel Load AC Current, F...
Page 20 - Part 2—CX Series Application Guide; VIII. Distributed lines
19 Part 2—CX Series Application Guide W ith the helpful advice and input from contractors and consultants around the world, engineers at QSC designed the CX Series amplifiers to be a versatile and reliable foundation for high-quality installed sound systems. This applications guide will help you des...
Page 21 - IX. Designing the Distributed Sound System; LOUDSPEAKER COVERAGE AND PLACEMENT
20 1watt in 1 meter 2 meters 3 meters 92 dB SPL 86 dB SPL 82.5 dB SPL 80 dB SPL 4 meters sensitivity = 92 dB, 1 watt@1m IX. Designing the Distributed Sound System There are several main steps in designing a distributed sound system: • Determining loudspeaker coverage and placement • Determining powe...
Page 23 - DETERMINING POWER LEVELS
22 -10.0 -8.0 -6.0 -4.0 2.0 4.0 6.0 8.0 0.5 10.0 12.0 14.0 16.0 18.0 20.0 0.1 1 0.2 10 100 5 20 50 2 0.0 dB(ref1watt) Power(Watts) -2.0 DETERMINING POWER LEVELS After you’ve determined where to place the loudspeakers, you need to calculate the power each one requires. If the installation is in an ex...
Page 24 - EXAMPLE; SELECTING THE AMPLIFIER; would be the
23 EXAMPLE A loudspeaker (sensitivity: 94 dB @ 1W, 1 meter) in a busy office covers an area with an ambient noise of 72 dBA, measured at a seated person’s ear position at the desks. The client wants superb intelligibility, so your goal is to provide an SPL of 97 dB (72 plus 25) to the intended liste...
Page 25 - USING COMPONENTS WITH DIFFERENT VOLTAGES; the dB reduction to use with the derating chart below it.
24 USING COMPONENTS WITH DIFFERENT VOLTAGES Sometimes it may be practical to use a transformer or loudspeaker/transformer combination with a different voltage system from what it was originally intended. For example, a 70-volt transformer could be used in a 25- volt system, although you would have t...
Page 26 - more to compensate
25 X. How Many Speakers? How many loudspeakers can you connect to the distributed line? The amplifier itself determines the amount of audio power available to the line, and from that figure you must compensate for insertion loss in the speaker transformers and for headroom when you determine how muc...
Page 27 - XI. Other Design Considerations; SPEAKER TRANSFORMER SATURATION
26 XI. Other Design Considerations SPEAKER TRANSFORMER SATURATION Speaker transformers tend to be fairly small, and some vary widely in quality. They tend, therefore, to be prone to core saturation at low frequencies. Saturation occurs when the magnetic field induced in the transformer’s iron core b...
Page 28 - the CX4T, up to 150 watts for the CX6T up to 400 watts for the CX12T.; WIRE LOSS; determined by the formula
27 speaker, it will affect the sound level from the distributed line’s speakers also, possibly altering them from your intended levels. An alternate method is to attach an 8-ohm speaker across the 25-volt outputs. This provides up to approximately 80 watts to the speaker and makes more power availab...
Page 30 - AC Current Consumption; Heat Emissions
29 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)...
