QSC 1100 Owner'S Manual Download Page 4

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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.

The front panel presents essential user information and is recessed to prevent damage.  The green power indicator serves
as a pilot light and individual red clip indicators monitor overall performance of each channel.  The AC switch and circuit
breaker are front mounted for convenience and quick resetting.  Except for the  Model 1100, the Gain controls and input
programming switches have been placed on the back of the amplifier to protect them from damage, inadvertent adjustment,
or tampering.  The Gain controls, as well as a pair of headphone jacks, have been placed on the front panel of the Model
1100 to allow easy access in monitoring applications.

The amplifiers use a separate bipolar power supply for each channel, for minimum crosstalk, cross-distortion, and greater
reliability.  A single dual-secondary transformer feeds isolated, separately fused rectifiers and filter capacitors for each
channel.  Thus the remaining channel can keep running in case of breakdown.

In order to interface properly with a variety of pro-audio systems, we have included all of the popular input and speaker
connectors.  Balanced or unbalanced inputs can be made using XLR plugs, screw lugs to the barrier strip, or 1/4-inch phone
plugs (ring-tip-sleeve for balanced inputs).  Speaker connections are made with 5-way binding posts.

The steel chassis, of the 1200, 1400 and 1700, is a 14 gauge, single piece design with integral rack mounting ears.  The
1100 chassis features single piece aluminum extrusions that form the sides of the chassis and feature integral rack
mounting ears and heatsinks. The extra strength chassis and rugged mounting of internal parts contributes greatly to
QSC’s reputation for reliability by protecting the circuitry from years of road abuse.

All of these points are more fully explained in the following Sections.

1.4 SPECIFICATIONS

1100

1200

1400

1700

OUTPUT POWER (per channel)
Both Channels Driven

8 ohms, 20-20 kHz, 0.1% THD

50w

100w

200w

325w

4 ohms, 20-20 kHz, 0.1% THD

70w

150w

300w

500w

Bridged-Mono Operation

8 ohms, 20-20 kHz, 0.1% THD

140w

300w

600w

1000w

DYNAMIC HEADROOM  dB

8 ohms

2.0

2.0

2.0

1.9

4 ohms

2.3

2.5

2.5

2.9

DISTORTION, THD @ 8 ohms

20-20 kHz, at rated power

Less than 0.1%, 0.01% typical

SMPTE-IM at rated power

Less than 0.025%

FREQUENCY RESPONSE

20-20 kHz, +0, -1.0 dB at 1 watt

DAMPING FACTOR @ 8 ohms

Greater than 200

NOISE (A-weighted)

100 dB below rated power

VOLTAGE GAIN, dB

26

29

32

34

SENSITIVITY, V RMS

1.0

1.0

1.0

1.0

(for rated power, 8-ohms)

INPUT IMPEDANCE

10K unbalanced inverting
20K balanced or unbalanced non inverting

CROSSTALK

-70dB, 20-20 kHz

CONTROLS

AC Switch, Circuit Breaker, Gain Knobs, Input Programming DIP Switches,
and Bridging Switch

INDICATORS

Power:  Green LED       Clip:   Red LED

COOLING

Convection

Convection

2 speed fan

2 speed fan

Summary of Contents for 1100

Page 1: ...1 Owner s Manual A U D I O Rev C Model 1100 Model 1200 Model 1400 Model 1700 SeriesOne TD 000027 00 ...

Page 2: ...r enviter les risques d incendie ou d electrocution n exposez pas cet article a la pluie ou a l humidite AVIS RISQUE DE CHOCK ELECTRIQUE NE PAS OUVRIR SAFEGUARDS Electrical energy can perform many useful functions This unit has been engineered and manufactured to assure your personal safety Improper use can result in potential electrical shock or fire hazards In order not to defeat the safeguards ...

Page 3: ...e to include a copy of the sales receipt your name return address and phone number Mark the package Attention Service Department 2 Call QSC s Service Department 1 800 772 2834 and obtain a Return Authorization R A number Ship the product prepaid to QSC Audio Products We recommend UPS 3 We will determine if the product is under warranty a If it is we will repair and ship it back to you at no charge...

Page 4: ...LRplugs screwlugstothebarrierstrip or1 4 inchphone plugs ring tip sleeve for balanced inputs Speaker connections are made with 5 way binding posts The steel chassis of the 1200 1400 and 1700 is a 14 gauge single piece design with integral rack mounting ears The 1100 chassis features single piece aluminum extrusions that form the sides of the chassis and feature integral rack mounting ears and heat...

Page 5: ...spect 2 2 IMPORTANT PRECAUTIONS 2 21 The power must be OFF when making any connections If you connect plugs with the power on especially in dry environments static sparks or bad cables can cause pops or hums which can damage speakers 2 22 When first powering up the amp have the amplifier Gain controls all the way off in case of defective cables or hookups Turn the Gain controls up gradually until ...

Page 6: ...ed on the rear panel see the rear panel illustration for details They come factory set for normal stereo operation switches 1 2 and 7 8 up See section 3 5 for other cases 2 35 Octal Socket For normal operation nothing should be plugged into the octal socket It comes from the factory with a protective label to prevent corrosion of the pins 2 36 Input Connections The input polarity is as follows 1 4...

Page 7: ... Diode indicators monitor the operation of the amplifier A green LED serves as the pilot light to indicate that power is on Each channel has a red Clip indicator that will show any distortion in the amplifier Uponpowerup thesemaynotflashsymmetrically Thisdoesnotnecessarilyindicatethattheremaybeaproblem The muting circuit blocks the sound for three seconds after turn on and immediately after turn o...

Page 8: ... may cause heat build up unless good access to cool air is provided at the sides of the rack If side clearance and or louvers cannot be provided some space should be provided over and under the amplifier for air circulation PILOT LIGHT AC BREAKER CLIP INDICATORS AC SWITCH MODEL 1200 1400 FRONT OCTAL SOCKETS GAIN CONTROLS XLR INPUTS 1 4 INCH INPUTS BARRIER STRIP INPUTS MONO BRIDGE SWITCH AC CORD SP...

Page 9: ...erances Series One amplifiers are designed for safe operation at AC voltages l0 higher than rated however temperature rise and transformer hum may increase somewhat Operation on lower than normal AC voltages is not harmful to the amp but performance will be progressively lost For voltages down to 75 of rated voltage no effect other than loss of peak power should be noticed If voltage declines furt...

Page 10: ...ut Figure 3 34b 3 Pin XLR Balanced Output Connection 3 35 Unbalanced inputs Since the input signal responds to the difference between the plus and minus signals if only a single ended unbalanced signal is available the unused input terminal must be grounded for operation without loss of gain The ability to reject cable induced hum and noise is lost but this may not be needed in well shielded envir...

Page 11: ...nefits of a balanced line input can still be obtained Special cables will need to be made as follows Amp Input Figure 3 36 1 4 inch Quasi balanced Output Connection The cable end which connects to the power amplifier would be made as described in Section 3 34 using balanced line cable At the other end using whatever plug matches the unbalanced output connect the plus conductor to the signal termin...

Page 12: ...the QSC Sales Department for details on availability 3 44 Octal Module Installation Peel away the protective cover and plug in the module observing correct alignment of the guide post in the middle The input bypass switches for that channel must be turned off See Section 3 5 Certain other switches may need to be set in accordance with the type of module and combination of channels desired See the ...

Page 13: ...undly crimped These must then be screwed firmly under the binding posts Dual banana plugs are more convenient for portable systems and will normally accept at least 12 gauge wires 3 65 Cable Polarity Be sure to observe correct polarity at both the speaker and amplifier end Most present day speaker cable is color coded or polarized in some way Adopt a consistent wiring convention and stick to it We...

Page 14: ... 1 00 2 00 67 33 14 0 050Ω 0 63 1 25 89 44 12 0 032Ω 0 40 0 80 111 56 10 0 020Ω 0 25 0 50 133 67 20 ft 18 0 252Ω 3 15 6 30 27 14 16 0 160Ω 2 00 4 00 40 20 14 0 100Ω 1 25 2 50 57 29 12 0 064Ω 0 80 1 60 77 38 10 0 040Ω 0 50 1 00 100 50 40 ft 18 0 504Ω 6 30 12 60 15 7 16 0 320Ω 4 00 8 00 22 11 14 0 200Ω 2 50 5 00 33 17 12 0 128Ω 1 60 3 20 48 24 10 0 080Ω 1 00 2 00 67 33 8 0 050Ω 0 63 1 25 89 44 80 ft...

Page 15: ... EQ s active crossovers and mixers 3 8 PROTECTION FEATURES 3 81 Summary We have ensured that accidents mistakes and abuse will have the minimum possible chance of harming the amplifier or speaker The major challenge was to do this without impairing the audio performance into normal loads 3 82 Short Circuit Protection The active region in a power transistor is surprisingly small perhaps 1 5 of a in...

Page 16: ... on After turn off or loss of power for any reason the amplifier will mute within a quarter of a second The outputs of all Series One power amplifiers are DC protected and the circuits have no inherent turn on or turn off thumps Protective muting for the Model 1100 is handled by a small relay at the input The signal does not pass through the relay contacts but is shunted to ground during the mutin...

Page 17: ...dard signal level and at a standard distance from the speaker can really tell if you are getting the expected output 3 98 UNWANTED NOISES Hum in this case defined as a fairly rounded 60 cycle tone Severe hum usually is caused by broken cables or jacks with a disconnected ground shield This problem can also be caused by corroded connectors espe cially 1 4 inch types For this reason high reliability...

Page 18: ...h as breath pops dropped microphones etc 4 3 HORN DRIVER PROTECTION The compression drivers used with horns for high frequency reproduction have special protection requirements These devices are more delicate than large cone speakers and more vulnerable to overload damage In particular the driver has a low frequency limit which must be carefully observed Below this frequency the driver diaphragm c...

Page 19: ...cuits or at least fuses Fuses can be added which will blow in case of overloads the problem is to select a fuse with the correct time lag and overload characteristics to match the speaker limitations The speaker manufacturer is in the best position to specify these values the following table is presented for rough guidance only The fuse values shown are calculated for fast blow fuses which will ca...

Page 20: ...arts rattle around on the inside when the amp is turned over in all directions please have it serviced immediately as a loose part could lodge in a dangerous place and cause further damage or shock hazard 5 4 OBTAINING SERVICE If the amplifier isn t working properly please consult the troubleshooting chart in Section 3 9 If proper operation cannot be restored the amplifier may require service This...

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Page 22: ...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 ...

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