Instruction/ maintenance manual of the product 1400 QSC Audio
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1 Owner’ s Manual ® A U D I O Rev. C Model 1 100 Model 1200 Model 1400 Model 1700 ▲ ▲ ▲ ▲ Series One *TD-000027-00*.
2 EXPLANATION OF GRAPHICAL SYMBOLS The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the user to the presence of uninsulated “ dangerous voltage ” within the product ’ s enclosure that may be of sufficient magnitude to constitute a risk of electric shock to humans.
3 I. INTRODUCTION 1.1 WELCOME Thank you for selecting a QSC Series One power amplifier for your audio system. Our goal is to ensure your complete satisfaction with your amplifier purchase. Please do not hesitate to call your QSC Dealer or QSC Audio Products if you have any service problems or questions not answered in this manual.
4 automatically as soon as safe operation is assured. An equally important muting circuit protects the loudspeakers from unexpected damage, by muting the amp during turn-on and turn-off and by blocking DC faults, whether caused by the amplifier or preceding components.
5 AMPLIFIER PROTECTION Full Short Circuit, Open Circuit, Over-Temp, Ultrasonic and RF Protection. Stable into reactive or mismatched loads. SPEAKER PROTECTION DC Load Fault Protection 3 Second Turn-on.
6 2.27 High voltages can be present on the speaker terminals. Always connect speaker terminals with the power off, and use heavy gauge cable with no frayed strands or damaged insulation.
7 2.39 Operation and Indicators Note that the Gain controls are calibrated in dB. As you turn the Gain down, it takes more input signal to reach full power, so the Gain should be kept in the upper 12 dB of its range for full power output from normal signal sources.
8 III: OPERA TION 3.1 COOLING 3.11 The Model 1100 uses side-mounted, convection-cooled heat sinks for power transistor cooling. When rack mounted, temperature rise should not be excessive for eight-oh.
9 3.12 The Model 1200 uses an internal heat radiator, top ventilation slots, and the faceplate for cooling. The faceplate will get quite warm in severe usage, but this heatsink system will serve adequately when the amp is used in the open air.
10 mismatches will result in slight loss of common-mode rejection, but will still have much greater noise rejection than unbalanced inputs. 3.34 Balanced Inputs For proper balanced-line operation, the cable shield should be connected at the power amplifier end only and kept separate from both signal conductors.
11 3.36 Unbalanced Inputs and Polarity Unbalanced operation raises an interesting question regarding the trade-offs between maintaining standard system polarity and optimal stability.
12 3.38 Good Quality Connections A tight and corrosion-free contact at all connections is essential for good sound and to avoid erratic noises or unstable performance. 1/4-inch connectors are suitable for low-cost portable systems, but must be removed and replaced frequently to avoid corrosion build-up.
13 Connect the amplifier input to Ch. 1 only, and use only the Ch. 1 Gain control, which now controls the entire amplifier. Do not feed another input into Channel 2. The Ch. 2 Gain control should be kept off for safety. An 8 or 16 ohm speaker load should be connected across the two red speaker terminals, using the red terminal of Ch.
14 loss of 10% is barely audible, the resultant low damping factor will prevent the amplifier from fully controlling the peaks and dips in frequency response caused by speaker impedance variations. This will result in greater coloration and muddiness.
15 3.7 25 AND 70 VOLT SYSTEMS 3.71 Introduction Commercial sound systems commonly use dozens or even hundreds of speakers for sound distribution. Special methods for connecting and controlling many separate speakers have been worked out by commercial sound contractors.
16 3.83 Thermal Protection In case of blocked ventilation, improper loading or prolonged short-circuit operation, the temperature of the power transistors can rise to excessive levels. If the temperature of the heat sink rises to 85C, a thermostat will remove power to that channel.
17 then the fault is somewhere in the bad channel. Check the input program switches, octal accessory (if any) or jacks. See Section 3.5 for correct switch settings. Inspect the binding posts for damage, and try a different input jack or the parallel channel switches before giving up on the channel.
18 that stage. Assuming that the hiss has not always been there, this indicates defective electronics. Certain special- effects units are rather noisy, so compare with other users.
19 You may have some problems finding the larger value capacitors in the preferred film-type construction. If necessary, several can be paralleled; simply add the individual capacitances together to get the total rating. You will probably have to locate non-polar electrolytics for values greater than 10-20uf.
20 V : MAINTENANCE AND SER VICE 5.1 CLEANING The faceplate and chassis can be cleaned with a soft cloth and mild non-abrasive cleaning solution, such as Windex. Avoid cleaning powders or scrubbing pads, as these will scratch and dull the paint. Be sure to unplug the unit prior to cleaning.
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22 ® A U D I O “ QSC ” is a registered trademark of QSC Audio Products, Inc. 1675 MacArthur Blvd. Costa Mesa, CA 92626 (714) 754-6175 FAX (714) 754-6174.
An important point after buying a device QSC Audio 1400 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought QSC Audio 1400 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data QSC Audio 1400 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, QSC Audio 1400 you will learn all the available features of the product, as well as information on its operation. The information that you get QSC Audio 1400 will certainly help you make a decision on the purchase.
If you already are a holder of QSC Audio 1400, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime QSC Audio 1400.
However, one of the most important roles played by the user manual is to help in solving problems with QSC Audio 1400. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device QSC Audio 1400 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
