QSC Audio Stereo Amplifier SRA 1222 User Guide

SRA1222  
SRA2422  
SRA3622  
Studio Reference Amplifier  
User Manual  
*TD-000107-00*  
TD-000107-00 rev.A  
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TABLE OF CONTENTS  
INTRODUCTION  
General Overview..........................................................................................4  
Illustrations.............................................................................5  
UNPACKING  
Unpacking and Inspection..................................................................................6  
What is Included.............................................................................................6  
SETUP  
Stand-alone Mounting....................................................................................6  
Rack Mounting...............................................................................................7  
Supporting the Rear of the Amplifier..........................................................9  
Gain Control Security Cover.....................................................................10  
Cooling Requirements...................................................................................12  
AC Power Requirements..............................................................................13  
Operating Mode Selection..........................................................................14  
Clip Limiters................................................................................................18  
Low Frequency Filters..................................................................................19  
CONNECTIONS  
Inputs:  
General Use and Recommendations..................................................20  
XLR and RCA Connector Pinouts..................................................21  
Outputs:  
General Use and Recommendations.................................................22  
Binding Posts.................................................................................23  
Speakons...................................................................25  
Remote On/Off (Remote Trigger).......................................................................28  
DataPort.................................................................................................31  
USE  
AC Power Switch.........................................................................................32  
Gain Controls................................................................................................32  
Signal and Clip LED indicators......................................................................32  
APPLICATION EXAMPLE...........................................................................................33  
TROUBLESHOOTING......................................................................................34  
SPECIFICATIONS............................................................................................................36  
WARRANTY INFORMATION ..............................................................................................38  
HOW TO CONTACT QSC AUDIO PRODUCTS ...........................................................38  
3
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INTRODUCTION- General Overview  
QSC’s SRA Series Amplifier  
Congratulations on your purchase of the SRA (Studio Reference Amplifier)Series power amplifier. To help  
you obtain the best results from your purchase, we encourage you to carefully review this manual. With  
information including connections, configuration and operation, it offers many useful guidelines.  
Building upon QSC’s widely recognized reputation throughout the cinema industry as “The Power Behind the  
Pictures,” the SRA Series of power amplifiers bring world-class audio performance to recording studios,  
high-end home theaters, and numerous additional applications. This SRA Series manual encompasses three  
models- the SRA1222, SRA2422, and the SRA3622 - with power points ranging from 200 to 750 watts per  
channel @ 8 ohms. These amplifiers draw upon QSC’s expertise in high frequency switching power supplies  
and include the popular DataPort for integration with optional QSC crossover and DSP modules.  
The SRA’s exemplary performance is a result of QSCs high current output section and advanced HF switch  
mode power supply technology that enables these amplifiers to weigh considerably less than conventional  
transformer driven models while also occupying less rack space. This patented technology delivers crystal-  
clear highs, smooth and accurate mids, and a powerful, articulate low-end response - providing realism to  
your audio playback. Further, a full complement of connectors facilitates easy integration into virtually any  
environment.  
QSC’s SRA Series amplifiers also boast useful features such as individually selectable clip limiters and  
subsonic filters, front-mounted lockoutable gain controls, plus signal and clip LED indicators to monitor  
performance. SRA Series amplifiers can be configured for stereo, parallel, or bridge mono operation. As  
expected from the world’s largest manufacturer of professional power amps with an unparalleled reputation  
for reliability and customer support, the SRA Series amplifiers deliver performance you can count on.  
SRA Features  
• Active inrush limiting- will not trip circuit breakers at turn on  
• A hum-free noise floor and ultra low distortion  
• Optional DSP modules for the ultimate in custom applications  
• Short circuit, DC, subsonic, and thermal overload protection  
• Gain control security cover prevents misadjustments  
• LED indicators for power, signal, and clip  
• Detachable rack ears included  
• Only 10 kg (22 lb.) for easy racking and shipping  
• Selectable subsonic filters: off, 20 Hz, or 50 Hz  
4
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INTRODUCTION- Illustrations  
Front Panel (gain control security cover removed)  
1- Power switch  
2- Channel 1 gain control  
4- Channel 1 signal and clip indicators  
5- Channel 2 gain control  
6- Channel 2 signal and clip indicators  
3- Power “on” indicator  
Note! Amplifiers are shipped with the gain controls set at maximum  
gain (+29 dB) and with gain control security cover installed. See page  
10 for security cover removal and installation information.  
Rear Panel  
1- DataPort connector  
11- Channel 2 Speakon output connector  
12- Channel 1 binding post output connectors  
13- Channel 2 binding post output connectors  
14- Cooling air intake vents  
15- Remote trigger in/out jacks  
16- Remote Trigger pinout reference chart  
17- Serial number decal location  
2- Channel 1 RCA input connector  
3- Channel 2 RCA input connector  
4- Channel 1 XLR input connector  
5- Channel 2 XLR input connector  
6- Mode switches  
7- XLR connector pinout reference chart  
8- Channel 1 Speakon® pinout reference chart  
9- Channel 1 Speakon output connector  
10- Channel 2 Speakon pinout reference chart  
18- Mode switch settings reference chart  
19- AC power cord entry (IEC inlet)  
5
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UNPACKING AND INSPECTION  
The SRA amplifier is highly durable and carefully packaged. We recommend you inspect the unit carefully  
after removing it from the packaging, as occasionally there may be damage due to some unfortunate  
incident during shipment. Report any damage to the shipping carrier. We recommend saving the carton and  
packing material in case the unit must be shipped back to your dealer, distributor, or service center. Also  
note: some freight companies consider damage claims without the original packing materials invalid.  
The QSC shipping box should contain:  
1- The SRA amplifier  
2- This Owner’s Manual  
3- Accessory packet containing:  
-rack mount ears (2, used for rack mount installation only)  
-four adhesive feet (for non-rack mounting installation)  
-5/64” hex key (Allen wrench) for gain control security cover removal  
-remote on/off (trigger) control cable, 36” long  
4- IEC Power Cord  
SETUP- Stand-alone Mounting  
If the amplifier is to be used “stand-alone” (not mounted in an equipment rack) install the self-adhesive rubber  
feet on its bottom surface. The self-adhesive rubber feet are included with the amplifier.  
To install the self-adhesive rubber feet:  
1- Turn the amplifier upside down on  
a soft, nonabrasive surface.  
2- Peel the backing paper off of each  
rubber foot and place near each of  
the four corners of the chassis  
bottom  
3- Press firmly to activate the  
pressure sensitive adhesive.  
4- Turn the amplifier back over so  
that the rubber feet rest on the  
supporting surface.  
6
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SETUP- Stand-alone mounting (cont’d.)  
Dimensions shown are  
useful for non-rack  
mount installations.  
Rack Mounting  
Rack mounting the amplifier  
Rack mounting is optional. The amplifier fits a 483 mm (19”) width equipment rack.  
To rack mount the amplifier:  
1- Install the rack mount ears (see below and the following page for details).  
2- Position the amplifier in the equipment rack and secure all four corners of the front panel using  
machine screws and washers. The size and thread type of the screws is determined by the equip-  
ment rack. Washers should be large enough to prevent the screw head from slipping into the rack  
ear mounting hole. Plastic washers will help prevent the screws from scratching the front panel.  
To attach the rack mounting ears, you will need:  
1- A #2 size cross point (Phillips) screwdriver.  
2- The rack mount ears included with you SRA amplifier.  
Continued, top of next page.....  
7
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SETUP- Rack Mounting  
Continued, from previous page.....  
Attaching the rack mount ears:  
1- Remove the two screws holding the front panel end cap  
in place. Use a #2 cross point screwdriver (Phillips).  
2- Place the rack mount ear as shown, aligning it so the  
screws will go back into their original locations.  
3- Insert the screws and tighten being sure to keep the rack  
mount ear properly aligned.  
4- Repeat procedure for the other side  
When installing equipment into a rack, distribute  
the units evenly. Otherwise, hazardous conditions  
may be created by an uneven weight distribution.  
Dimensions for rack mount installations.  
Note: Some dimensions are taken from  
the front surface of the rack rail.  
8
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SETUP- Supporting the rear of the amplifier  
Supporting the rear of the amplifier  
If transporting the amplifier in a loaded equipment rack, support the rear of the amplifier using rear  
rack ears. They are optional and not included with the amplifier. QSC’s Technical Services Group has  
the rear rack ear kits for sale.  
The rear ear kit mounts two ways (shown below):  
- using machine screws to secure the amplifier to the rear ears  
- using a post and the notch to support the rear.  
Refer to the instructions that come with the optional  
rear rack ear kit! Information is for reference only.  
Method 1- The amplifier is  
first installed and secured  
to the front rack rails. The  
rear ears are then secured  
to the amplifier and to the  
rails using screws.  
Method 2- The post is  
installed on the rear ears,  
then the ears attached to  
the rack using screws. The  
amplifier is then installed  
from the front of the rack  
and the notch in the  
amplifier’s rear chassis tab  
slides over the post.  
9
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SETUP- Removing the Gain Control Security Cover  
Gain Control Security Cover  
The amplifier is shipped with its gain controls at  
their maximum setting of +29 dB and a security  
cover installed to prevent tampering.  
To adjust gain settings, remove the cover. Reinstall  
the cover to prevent unintentional changes.  
Cover retaining tab detail (left) and corre-  
sponding chassis retaining slot (right).  
Removing the Security Cover  
1- Using a 5/64” (or 2 mm) hex key, remove the  
covers retaining screw and set it aside.  
2- Insert the end of the hex key tool into the  
cover’s screw hole and pull/swing the plate out as  
shown.  
3- Once the right side has been withdrawn from  
its retaining slot, pull the gain control lockout  
plate out from the front panel recess.  
(continued, following page)  
10  
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SETUP- Installing the Gain Control Security Cover  
4- Gain controls exposed for adjustment.  
Installing the Gain Control Security Cover  
1- Slide the cover into the front panel recess.  
Push it fully to the right and against the front  
panel. You should feel the cover’s retaining  
tabs drop into the slot in the front panel.  
2- While lightly pressing the right side of the  
cover against the chassis, use the hex key  
tool (inserted into the plates screw hole) to  
slide the cover to the left until the LEDs line  
up with the cover’s holes. Continue to lightly  
press the cover against the chassis while you  
insert the cover’s retaining screw and secure  
the screw. Fully tighten the retaining screw.  
11  
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SETUP- Cooling Requirements  
Cooling Air Inlet and Exhaust Vents  
The amplifier has a rear-mounted variable-speed  
fan. Speed is determined by the temperature of  
the amplifiers internal heat sink assembly.  
Cooling air enters the rear of the amplifier and  
exhausts from the front vents.  
If mounting in an enclosure, be certain not to  
restrict airflow.  
Warm air  
exhausts  
through  
the front  
panel  
Cool air is  
pulled into the  
rear of the  
amplifier.  
vents.  
Fan  
Amplifier  
Equipment Rack  
Do not obstruct cooling air vents!  
12  
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SETUP- AC Power Requirements  
AC Power  
Verify operating voltage before plugging  
amplifier into AC mains. Make sure the AC  
mains voltage is the same as specified on the  
serial number plate.  
Do not use a smaller gauge cord than supplied  
with the amplifier! 120 Volt models are sup-  
plied with a #14 AWG cordset. 220 Volt models  
are supplied with 1.0 mm2 cordset.  
The serial number plate is affixed to the rear panel,  
bottom right corner, adjacent the AC cord entry.  
Do not use improper AC mains  
voltage! It can create hazardous  
conditions and severely damage  
the amplifier!  
Typical AC Line Current Consumption  
5.0 amps  
at 8 ohms  
8.0 amps  
at 8 ohms  
5.6 amps  
at 4 ohms  
Conditions: 120 VAC line, both channels  
driven with pink noise at 1/8 rated power.  
AC Power Connection  
Plug the IEC-style end of the cord into the amplifier. Plug the AC mains-end of  
the cord into the AC outlet.  
120 Volt Models, 15 Amp Receptacle.  
IEC Inlet  
Insert the plug fully.  
(amplifier end of cord)  
Orient the IEC-style connector  
correctly with the inlet, then  
insert the plug fully.  
240 Volt Models, European three  
conductor Earthing Receptacle  
Insert the plug fully.  
13  
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SETUP- Operating Mode Selection  
Mode Switches  
The mode switches are located on the rear panel.  
The switches are recessed to prevent accidental  
changes. It is best to set the switches as re-  
quired before mounting the amplifier in an  
equipment rack as they may become difficult to  
access.  
Change switch positions by sliding the switch  
left or right. Operate the switches with a small,  
flat-tip screwdriver or similar tool. Do not use a  
pencil or other item that could break and fall into  
the amplifier.  
The possible operating modes are Stereo (Biamp  
application uses Stereo mode, too), Parallel, and  
Bridge. Each is described in detail on pages 14  
through 17. Additionally, clip limiting and low  
frequency filtering are switchable on each  
channel. Page 18 and 19 describes the clip limiter  
and LF filter operation.  
Mode Switches are located on the rear panel.  
Note:  
The block diagrams in this section do not show all the required  
connections. They are simplified to convey the main operating  
principles of each operating mode. For detailed connection  
information, refer to pages 20 through 29.  
Stereo Mode  
In stereo mode, each input signal is  
sent to its respective channel. Each  
SRA amplifier  
CH1 Input  
channel has independent gain  
control, clip limiting, filtering, input,  
and output connection.  
CH1  
Output  
XLR or RCA  
Full range  
loudspeakers  
Mode switches  
set for stereo  
To operate in stereo mode, set the  
mode switches for stereo. Set  
switches 4, 5, 6 and 7 to the left.  
Connect the two input signals and the  
two speakers.  
CH2 Input  
CH2  
Output  
XLR or RCA  
Continued, top of next page.....  
14  
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SETUP- Operating Mode Selection: Stereo  
Stereo Mode Notes:  
•To operate in stereo mode, set switches 4,  
5, 6, and 7 to the left position.  
•Input connections: connect one input to CH1  
and the other to CH2. Use the XLR or RCA  
connectors.  
•Output connections: using the binding posts  
or the Speakon connectors, connect CH1 and  
CH2 outputs to their respective speakers.  
Stereo Mode: mode switches 4, 5, 6, and 7 to the left.  
Biamp Notes:  
Biamp Applications- Use Stereo Mode  
• Switch settings are the same as for stereo  
mode (see top of page).  
Mode switch settings for biamp are the same  
as for stereo. Multi-amp applications (like  
biamp) split the signal into different ranges  
before amplification, dedicating each channel  
to a specific task. The signal processing takes  
place externally before the signal is amplified.  
•Audio inputs to amp must be preprocessed.  
•Input connections: connect one input to  
CH1 and the other to CH2. Use the XLR or  
RCA connectors.  
•Output connections:  
binding posts or Speakon  
connectors, connect CH1  
SRA amplifier  
and CH2 outputs to their  
respective speakers. CH1  
LF  
Output  
Full range  
input signal  
to processor  
Low frequency  
processor output  
feeds CH1  
CH1  
Output  
Speakon can output both  
channels if 4 wire cable is  
used.  
XLR or RCA  
LF  
loudspeaker  
Mode switches  
set for stereo  
Signal processor  
configured as crossover  
• Verify all signal routing  
and test your configuration  
at low power to avoid  
damaging speakers.  
High frequency  
processor output  
feeds CH2  
HF  
Output  
CH2  
Output  
XLR or RCA  
HF  
loudspeaker  
•QSC’s DSP modules are  
ideal for biamp mode  
applications.  
15  
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SETUP- Operating Mode Selection: Parallel  
Parallel Mode  
In parallel mode, channel 1 and  
channel 2 XLR inputs are connected  
SRA amplifier  
CH1 XLR Input  
in parallel. Applying an input signal  
to either XLR input will drive both  
channels.  
CH1  
Output  
Each channel still has independent  
gain control, clip limiting, and  
output connection, just like stereo  
mode.  
Full range  
loudspeakers  
Mode switches  
set for parallel  
Do not use CH2  
input! CH2 input is  
connected internally  
from CH1.  
CH2  
Output  
Do not use the RCA inputs if  
operating in parallel mode.  
Parallel Mode Notes:  
•Do not use the RCA inputs for parallel mode.  
•Set switches 4, 5, and 6 to the right and  
switch 7 to the left.  
•Connect the single input signal to either CH1  
or CH2’s XLR input connectors.  
•Output connections: binding posts or Speakon  
connectors, connect CH1 and CH2 outputs to  
their respective speakers.  
•Since parallel mode connects both channels  
XLR inputs in parallel, the unused XLR can be  
used to daisy chain the input signal to another  
piece of equipment (see p.21).  
Parallel Mode: mode switches 4, 5, and  
6 to the right and switch 7 to the left.  
16  
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SETUP- Operating Mode Selection: Bridge  
Bridge Mode  
SRA amplifier  
In bridge mode, both output  
channels are interconnected into  
CH1 Input  
one, higher power output. The  
result is one output with about 4  
times the peak power and about 3  
times the sustained power of a  
single channel.  
CH1+  
Output  
XLR or RCA  
Mode switches  
set for bridge  
Do not useCH2  
input! CH2 input  
is internally  
bridged with  
Single, high power  
loudspeaker  
Use CH1’s gain control, clip limiter,  
and LF filter. Use channel 1’s XLR or  
RCA input.  
CH2+  
Output  
CH1.  
Output connection is different for  
bridge mode; the positive output for  
each channel gets connected to the  
loudspeaker. Page 24 details bridge  
mode output connections for  
binding posts, and page 26 for  
Speakon bridge output connections.  
Bridge Mode Notes:  
•To operate in bridge mode, set switches 4, 5, 6  
to the left and switch 7 to the right position.  
•Input: Use CH1’s XLR input connector.  
•Output connections: Use the two red binding  
posts. CH1 red binding post= positive, CH2 red  
binding post= negative; or use CH1 Speakon  
terminal 1+ and 2+ (1+ is positive).  
•Use CH1’s LF filter, clip Limiter, and gain  
control. Set CH2s clip limiter to the same  
setting as CH1s.  
Bridge Mode: mode switches 4, 5, and 6  
to the left, and switch 7 to the right.  
17  
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SETUP- Clip Limiter  
Clip Limiters  
The SRA has separate clip limiters for each  
channel which respond only to actual amplifier  
clipping. Amplifier clipping generates internal  
error signals which cause the clip limiter to  
quickly reduce amp gain and minimize the  
overdrive. To preserve as much of the program  
dynamics as possible, limiting occurs only  
during actual clipping.  
Each channel has its own clip limiter switch  
that can be operated independently. Switch 1  
operates CH1’s clip limiter and switch 10  
operates CH2’s clip limiter.  
Channel 1’s clip limiter is operated by switch 1.  
Channel 2’s clip limiter is operated by switch 10.  
CLIP LIMITER ON: To turn the limiter on, slide the switch to the right (Sw.1: Ch.1, Sw.10: Ch.2).  
CLIP LIMITER OFF: To turn the limiter off, slide the switch to the left.  
Clip Limiting Tips  
Clip limiting reduces extreme overdrive peaks, allowing a higher average signal level without audible  
distortion. Increasing the gain with the clip limiter engaged, until clipping is again audible, can double  
the average output power. Be careful not to exceed the power rating of your speakers.  
The clip limiter is set to respond quickly after clipping is detected. On low frequency material, this may  
be perceived as a “rubbery” effect. It may be preferable to turn clip limiting off, and let the amp clip  
occasionally, especially if the speakers are robust.  
If operating in Bridge mode, set CH2s clip limiter to the same setting as CH1’s clip limiter.  
18  
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SETUP- Low Frequency Filter  
Low Frequency Filters  
Unless you already have filtering in the signal path  
preceding the amplifier, use the low frequency filter to  
protect your speakers from cone overexcursion caused  
by frequencies below the speaker’s limits. The speaker’s  
documentation will specify the low frequency limit.  
Generally, match the frequency selection to your  
speakers low frequency capability. This improves  
speaker performance by limiting subaudio cone move-  
ment, making more power available for the speakers  
rated frequency range.  
Each channel has its own low frequency filter. Channel  
1s low frequency filter is operated by switches 2 and 3.  
Channel 2s filter is operated by switches 8 and 9.  
Channel 1’s low frequency filter is operated by  
switches 2 and 3. Channel 2’s filter is operated  
by switches 8 and 9.  
FILTER ON: To turn the filter on, slide the switch to the right (Sw.2: Ch.1, Sw.9: Ch.2).  
FILTER OFF: To turn the filter off, slide the appropriate switch to the left.  
20 HERTZ: To set the filter for a 20 Hz. rolloff, slide the switch to the right (Sw.3: Ch.1, Sw.8: Ch.2).  
50 HERTZ: To set the filter for a 50 Hz. rolloff, slide the appropriate switch to the left.  
NOTE! The filter on/off switch must be set to the “on” position for the frequency  
selection to be active. If the on/off switch is set to the “off” position, no filtering will  
take place regardless of the frequency selection.  
SRA Series amplifier low  
frequency response curves.  
Output (dB)  
Frequency (Hertz)  
19  
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CONNECTIONS- Inputs, General Information  
Audio Input Connections  
Input connections to the SRA can be made with  
balanced XLR connectors for all operating modes,  
or unbalanced RCA connectors for Stereo and  
Bridge mode. We recommend using the balanced  
XLR connectors whenever possible. Unbalanced  
connections are prone to noise and interference  
pickup as well as ground-loop induced hum.  
circuitry inserts a small impedance between the  
RCA connector’s “ground” and the chassis ground.  
If the mode switches are set for parallel mode, the  
XLR input connectors are directly wired in parallel.  
This means the input can be connected to either of  
the XLRs and the remaining XLR can be used for  
daisy-chaining the input signal to other equipment  
(shown opposite page, bottom). Do not daisy chain  
from an RCA connector. Make sure only one input  
signal is applied to the amplifier when operating in  
Parallel or Bridge modes.  
The XLR connectors are precision balanced (0.1%  
tolerance on balancing resistors) and provide  
superior audio performance over the RCA connec-  
tors. The RCA connectors are unbalanced and thus  
prone to ground loop and common-mode noise  
pickup (as are all unbalanced connections).  
If your system has noise or hum, disconnect all  
amplifier inputs to verify the source of the noise. If  
the noise disappears, the noise source is not the  
amplifier. Check cabling and other equipment  
connections (see p.35 for troubleshooting).  
The RCA connectors have special circuitry added to  
help minimize ground-loop induced hum. This  
Input Connector Use  
Use the RCA, XLR, or  
RCA  
(unbalanced)  
DataPort connectors  
for signal input to  
the amplifier. Do not  
mix input connector  
usage.  
OR  
XLR  
(balanced or unbalanced)  
Use balanced  
connections  
and high-  
OR  
quality cable  
and connec-  
tors for best  
results.  
DataPort  
(refer to DataPort accessory’s instructions)  
20  
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CONNECTIONS- Inputs: XLR and RCA Connector Pinouts  
XLR Connector Pinout  
Jumper  
Balanced  
Unbalanced  
pin 2  
pin 3  
pin 1  
pin 2  
pins 1 and 3  
RCA (phono plug) Connector Pinout  
Signal (+)  
Ground  
Daisy Chain Example (parallel mode only)  
All amplifiers being daisy chained must be in parallel mode.  
Input signal  
21  
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CONNECTIONS- Outputs: Selecting Speaker Cable, Connecting to Loudspeakers  
Connecting the Outputs to the Loudspeakers  
There are two basic speaker connection  
configurations for the SRA amplifier. Stereo  
and parallel modes use two separate output  
connections (two loudspeaker loads). Bridge  
Do not use less than 4-ohm  
loads in Bridge mode!  
Note polarity of connec-  
tions for Bridge mode.  
mode uses one output connection (one loud-  
speaker load).  
WARNING! Use proper  
speaker wire.  
Stereo or Parallel Mode:  
Use NEC Class 2 wiring.  
Bridge Mode: Use NEC  
Use either the binding post or the Speakon  
output connectors. Each connector type is  
detailed in the following sections.  
Class 1 wiring.  
Refer to local and national  
electrical codes to assure  
code compliance.  
Refer to the diagrams provided for speaker  
connection. Mode descriptions (stereo, paral-  
lel, bridge, or biamp) and using the mode  
switches is shown on pages 14 through 17.  
Selecting Speaker Cable  
Use the highest quality loudspeaker cable available, which may or may not be the most expensive.  
Look for...  
• ...large conductor size: #10 AWG is the largest that will fit the binding posts. Smaller  
wire sizes, like #12 or #14 AWG may be fine for shorter speaker cable use. Avoid small  
sizes like #16 and up.  
• ...the conductors to be stranded. The higher the “strand count”, the more flexible and  
long-lived the cable will be. This means less stress on the output connectors of your  
amplifier and higher reliability. Solid wire is not recommended; it stresses the connectors  
and will fail when flexed.  
• ...quality insulation. The insulation should be thick enough to protect the conductors  
wherever they are installed and be flexible enough that handling the cable is not difficult.  
If operating in extreme cold temperatures, be sure your cable insulation will still be  
flexible. If operating in extreme hot conditions, be sure not to exceed the cables maximum  
rated operating temperature.  
• ....quality copper. This is hard to judge; it’s best to use name brand cable you trust.  
Cables made of recycled copper of unspecified resistivity have some risk. When in doubt,  
measure the resistance of a known length of cable and compare to standard wire table  
data. Whether or not the copper has small amounts of oxygen is of little impact.  
NOTE! AWG is the abbreviation for American Wire Gauge. The  
smaller the gauge number, the larger the physical size of the wire.  
Example: #10 AWG is a bigger, thicker wire than #16 AWG.  
22  
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CONNECTIONS- Outputs: Binding Posts  
Using the Binding Posts  
The binding posts support several connection methods;  
banana plugs, spade lugs, or direct wire connection.  
European models do not support the use of banana  
plugs.  
If using banana plugs, plug into the binding post  
directly.  
If using spade lugs, refer to the diagram, below, for  
acceptable dimensions of lug.  
If connecting the cable directly, strip about 1/2-inch of  
insulation from the ends and neatly twist any loose  
strands. Loosen the retaining nut fully, insert the wire,  
and tighten. Do not overtighten! Maximum wire gauge  
is #10 AWG (2.58 mm diameter).  
Binding post outputs on the rear panel.  
Continued, following page.....  
13 mm  
1/2”  
2.58 mm max. diameter  
#10 AWG maximum  
WARNING! Use  
proper speaker  
wire. Stereo or  
Parallel Mode: Use NEC  
Class 2 wiring. Bridge  
Mode: Use NEC Class 1  
wiring. Refer to local and  
national electrical codes to  
assure code compliance.  
19 mm  
3/4”  
6.3 mm minimum  
0.25” minimum  
European models do not  
have banana plug feature.  
12.9 mm maximum  
0.51” maximum  
23  
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CONNECTIONS- Outputs: Binding Posts  
Stereo and Parallel Mode output  
connections using binding posts  
Connect each set of binding post outputs to its  
respective loudspeaker.  
Z= 2 ohms minimum  
Maintain proper polarity when hooking up loudspeak-  
ers. Connect each red binding post (+, or positive) to  
the red (or +, positive) terminal of each loudspeaker.  
Connect each black binding post (-, or negative) to the  
black (or -, negative) terminal of each loudspeaker. All  
amplifiers and loudspeakers must maintain proper  
connection polarity in order for bass response to be  
optimum.  
Z= 2 ohms minimum  
Bridge Mode output connec-  
tions using binding posts  
Z= 4 ohms minimum  
Connect channel 1’s red binding post (+,  
positive) to the loudspeaker’s red (+, or  
positive) terminal. Connect channel 2’s  
red binding post (+, positive) to the  
loudspeaker’s black (-, or negative)  
terminal. If operating other amplifiers in  
bridge mode, make sure the connection  
polarity is maintained.  
Do not use less than 4-ohm loads in  
bridge mode! Note polarity of con-  
nections for bridge mode.  
24  
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CONNECTIONS- Outputs: Speakon connectors  
Speakon Outputs  
The Speakon connectors offer quick, reliable connection and disconnection of the speakers.  
Although more expensive than banana or spade-lug style speaker cable termination, the speed,  
convenience, and reliability make Speakon use popular with portable and live sound setups.  
The Speakons are wired:  
CH1 Speakon:  
Pin 1+ = CH1 positive  
Pin 1- = CH1 negative  
Pin 2+ = CH2 positive  
Pin 2- = CH2 negative  
CH2 Speakon:  
Pin 1+ = CH2 positive  
Pin 1- = CH2 negative  
WARNING! Use proper speaker wire.  
Stereo or parallel mode: Use NEC Class 2 wiring.  
Bridge mode: Use NEC Class 1 wiring.  
Refer to local and national electrical codes to assure code compliance.  
Two-conductor Speakon Cable  
Use two-conductor Speakon cable for stereo or parallel mode. Two cables will be required; one for CH1 and  
one for CH2.  
To Amplifier  
To Speaker  
Four-conductor Speakon Cable  
For biamp applications, use four conductor cable.  
Four conductor cable may be used for carrying both of the output channels with a single cable. Signal  
splitting required at loudspeaker end of cable.  
To Speaker  
To Amplifier  
25  
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CONNECTIONS- Outputs: Speakon connectors  
Stereo or Parallel Modes  
Stereo and Parallel modes  
use one cable for each  
channel. Each cable con-  
nects to its respective output  
connector and speaker.  
2 wire Speakon cables  
CH1’s Speakon can be used  
with a four conductor cable  
for carrying both outputs.  
The required signal splitting  
would take place at the  
speaker-end of the cable.  
Speakon cable wiring  
Bridge Mode  
Bridge Mode Speakon connection uses CH1’s Speakon only. Pin 1+ is the positive signal and Pin 2+ is the  
negative signal. NOTE! Make sure the speaker-end is wired according to its specifications. The diagram  
below assumes cabinet to be wired pin1+ and pin 1-. Verify proper connections are made!  
2 wire Speakon cable  
Speakon cable wiring  
WARNING! Use proper speaker wire.  
Stereo or Parallel Mode: Use NEC Class 2 wiring.  
Bridge Mode: Use NEC Class 1 wiring.  
Refer to local and national electrical codes to assure code compliance.  
26  
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CONNECTIONS- Outputs: Speakon Biamp Application  
Biamp Operation  
In biamp, one channel is used for lows, while the  
other channel is used for highs. It requires the use  
of signal processing equipment between the  
source material and the amplifier. Always test the  
system at the lowest practical power level for  
proper operation.  
efficient than are low frequency drivers, less  
power is required at higher frequencies. Biamp  
makes more efficient use of the power available  
from a given amplifier and provides more head  
room at lower frequencies. Triamp systems add  
one more level of frequency separation for amplifi-  
ers and speakers.  
Biamp-ready loudspeakers have no crossover and  
connect to the amplifier using the four-conductor  
Speakon. Some loudspeakers feature switchable  
passive or active (biamp) crossover configuration.  
Make sure any switchable loudspeaker is set for  
Active mode to disable the internal crossover if  
you are biamping.  
Conventional speaker crossovers consist of  
inductors, capacitors, and resistors. The heat  
generated in these components is power that could  
be delivered to the speaker. Near the crossover  
frequency, power loss can be close to 50%! No  
wonder professional sound companies prefer the  
multi-amplification approach. Biamp, triamp, or  
more...... it makes best use of the available AC  
power to produce sound.  
Amplifiers designed specifically for biamp opera-  
tion have different power points for each channel.  
Because high frequency drivers are much more  
4 wire Speakon cable  
Biamp-ready loudspeaker  
Speakon cable wiring  
27  
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CONNECTIONS- Remote on/off (remote trigger)  
Remote Trigger  
Remote turn-on and turn-off capability is provided by the remote  
trigger jacks on the rear panel. Remote trigger can be operated by  
two methods, 12 Volt DC or contact closure (switch, relay). The IN  
and OUT jacks can be used interchangeably as they are wired in  
parallel.  
The amplifier’s front panel power switch must remain in the  
ON position when using the remote trigger feature. The  
amplifiers power status is controlled from the remote trigger  
connections. If no plug is inserted in the remote trigger jacks,  
amplifier on/off is controlled by the front panel power switch.  
If a mono plug is inserted into either jack, the amplifier will go into  
standby mode (off). Apply +12 Volts DC to the tip and ground (- or  
negative) to the sleeve, and the amplifier will be enabled (on). Be  
sure to use a mono plug for +12 Volts DC remote trigger operation.  
If a stereo plug is inserted into either jack and no connections are  
made between the tip, ring, and sleeve, the amplifier will be  
enabled (on). If a contact connection (switch or relay contacts) is  
made between the sleeve and the ring, the amplifier will go into  
standby mode (off). The tip connection is not utilized when contact  
closure method is used.  
Remote Trigger Method  
12 Volts DC  
Type of Plug  
Power On (enable)  
Power Off (standby)  
Sleeve/Tip  
(mono)  
12 Volts DC  
0 Volts DC  
Ring/Tip/Sleeve  
(stereo)  
Contact Closure  
Contacts Open  
Contacts Closed  
28  
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CONNECTIONS- Remote on/off (remote trigger) 12 VDC Type  
12 VDC Remote Trigger  
12 Volt DC Remote Trigger  
Output. Connect to SRA  
amplifiers using mono mini  
plug (tip positive, +).  
For 12 Volt DC remote trigger  
operation, use a mono (2  
terminal) 3.5 mm mini-plug.  
Do not use a stereo (3 termi-  
nal) plug.  
Processor (or other “master” turn-on  
device) with 12 VDC remote trigger output.  
Connect a suitable two-  
conductor cable to the plug.  
Connect the tip of the plug to  
the + (or positive) polarity wire  
and the sleeve to the - (or  
negative) polarity wire.  
Turn the amplifier on (enable)  
by applying +12 Volts DC to  
the cable. Make certain that  
the + polarity of the 12 Volts  
DC connects to the tip of the  
plug!  
Turn the amplifier off (standby)  
by removing the voltage. This  
is normally done by turning off  
the main AC power switch of  
the processor (or other  
To additional 12VDC  
remote trigger inputs.  
AC-DC adapter with  
12VDC output  
primary system controller).  
Another possible remote on/  
off solution is shown to the  
right. This solution uses a 12  
Volt DC signal and a switch  
wired to the mono mini-plug.  
Make sure any AC adapter  
used is DC voltage output, not  
AC.  
to remote  
trigger in  
Note- We recommend the front panel AC power switch be switched to the  
“off” position anytime the system will not be operated for an extended period.  
This prevents the remote trigger from accidentally powering up the amplifier  
while you are away. It is a good idea to do the same with all remote turn-on/  
turn-off capable equipment when it is not to be operated for extended periods.  
29  
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CONNECTIONS- Remote on/off (remote trigger) Contact Closure Type  
Contact closure remote  
trigger output. Connect to  
SRA amplifiers using stereo  
mini plug (ring and sleeve).  
12 Volt DC Remote Trigger  
For contact closure remote  
trigger operation, use stereo  
(3 terminal) 3.5 mm mini-plug.  
Do not use a mono (2 termi-  
nal) plug.  
Processor (or other “master” turn-on device)  
with contact closure remote trigger output.  
Connect a suitable two-  
conductor cable to the plug.  
Connect the sleeve of the plug  
to one wire and the ring to the  
other wire. The tip of the plug  
is left unconnected.  
The other end of the cable is  
connected to a pair of switch  
or relay contacts. These  
contacts are typically inside  
the main AC power controlling  
device (processor) When the  
switch or relay contacts are  
closed, the amplifier will turn  
off. When the switch or relay  
contacts are opened, the  
To additional contact closure  
remote trigger inputs.  
amplifier will turn on.  
Another possible remote on/  
off solution is shown to the  
right. This solution uses a  
switch wired to the stereo  
mini-plug. The switch could be  
replaced with a set of relay  
contacts, should your applica-  
tion require it.  
to remote  
trigger in  
Connect contacts to sleeve and  
ring of stereo mini plug.  
Tip connection not used.  
Note- We recommend the front panel AC power switch be switched to the  
“off” position anytime the system will not be operated for an extended period.  
This prevents the remote trigger from accidentally powering up the amplifier  
while you are away. It is a good idea to do the same with all remote turn-on/  
turn-off capable equipment when it is not to be operated for extended periods.  
30  
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CONNECTIONS- DataPort  
What is a DataPort?  
The DataPort is a QSC-specific connection used for  
interfacing amplifiers, amplifier monitoring devices  
and signal processors. QSC Audio produces a line of  
digital signal processing as well as other accesso-  
ries that plug directly into the DataPort. The  
DataPort connection provides all the necessary  
interconnects between the accessory and the  
amplifier.  
For home theater and studio applications, DSP can  
be very useful for “tuning” the response of the  
system. For example, a QSC DSP-4 module con-  
nected to the amplifier could be configured as a  
crossover or a subwoofer filter, or many other  
functions. Audio response can be tailored using the  
DSP and its software to compensate for speaker  
response “dips” or “peaks”.  
DataPort is located on the left side of the rear panel.  
Contact your QSC representative or QSC Audio  
directly to find out what DataPort accessories might  
fit your application.  
Connecting  
In general, the connection is made by orienting the  
DataPort accessory or cable’s male HD-15 plug  
with the DataPort receptacle and inserting fully.  
Tighten the retaining screws. Do not use excessive  
force to tighten the retaining screws!  
Refer to the instructions included with your  
DataPort accessory for detailed connection infor-  
mation.  
A typical DataPort application shown with a program-  
mable QSC DSP-4 signal processor. The PC is required  
only for programming the DSP-4 and is not required to  
remain connected.  
31  
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USE- Front Panel Controls and Indicators  
AC Power Switch  
On the front panel, left side, is the Power switch.  
The switch is labeled ON, above it and to the left.  
To turn the power on: Press in on the upper  
portion of the rocker switch. The amplifier will go  
through its power-up cycle; the red-colored Clip  
LEDs will illuminate briefly, then the green-  
colored Power LED will remain on.  
To turn the power off: Press in on the bottom  
portion of the rocker switch. It may take a few  
moments for the Power LED to extinguish. This is  
normal.  
If the Power LED fails to illuminate when the  
power is switched on, check the power cord for  
proper connection at both ends and verify the AC  
power source is functioning properly.  
Signal and Clip LED Indicators  
SIGNAL- Illuminates when the input signal  
strength is sufficient to drive the output above -30  
dB relative to full output.  
CLIP- Illuminates when the input signal strength  
is strong enough to drive the output to the limits  
of the power supply (i.e. clipping).  
Clip Indicator Tips  
• Normally, the clip LEDs will flash occasionally  
when the amplifier is driven hard (high output  
level).  
Gain Controls  
• If Illuminated most of the time, the amplifier is  
being driven extremely hard and may eventually  
overheat, triggering the thermal shutdown circuitry.  
• If fully illuminated, the amplifier is in thermal  
shut down or short-circuit cutback is engaged.  
Reduce the input signal strength; if the Clip LED  
turns off, there is a problem with the speaker’s  
wiring or one of the speakers. If the LED remains on  
when input signal strength is fully reduced, the amp  
is in thermal shutdown. Reduce gain settings or  
input signal and allow the amp to cool down. Leave  
A gain control adjustment is provided for each  
channel. The voltage gain of the amplifier (in dB)  
is marked around each control.  
Rotating the control clockwise increases the gain  
applied to the signal. Rotating the control counter-  
clockwise reduces the gain applied to the signal.  
In stereo and parallel operating modes (see pages  
14 through 16) each channels gain is adjusted by  
its own control. In bridge mode, use channel 1s  
gain control and set channel 2s control fully  
counterclockwise.  
LED indicators.  
the power on so that the fan continues to run;  
operation will automatically resume after the  
amplifier has cooled sufficiently.  
32  
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APPLICATION EXAMPLE- 7.1 Surround  
7.1 Surround Application  
The block diagram, at  
right, shows how SRA  
amplifiers might be  
connected in a 7.1  
Processor  
home theater applica-  
tion. The connections  
SRA Amplifier: Left and Right Channels  
shown are simplified  
so as to convey the  
signal routing scheme.  
All amplifiers shown  
are operated in stereo  
mode. Amplifier inputs  
can be via the RCA or  
XLR connectors.  
Amplifier outputs can  
be via the binding  
posts or the Speakon  
connectors. Each  
SRA Amplifier: Center and Subwoofer Channels  
SRA Amplifier: Left Surround  
and Right Surround Channels  
SRA Amplifier: Left Back Surround and  
Right Back Surround Channels  
application/installa-  
tion is different; refer  
to you professional  
audio installer for  
detailed application  
solutions.  
Note: Loudspeaker  
orientaion is for  
ilustration only.  
Abbreviations and  
terms may vary by  
manufacturer.  
Subwoofer  
Center  
Left Front  
Right Front  
Right Surround  
Left Surround  
Left Rear Surround  
Right Rear Surround  
33  
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TROUBLESHOOTING  
The amplifier won’t turn on when the Power switch is operated (green Power LED not illuminating)-  
• Verify AC power source is providing required voltage. The simplest test is to plug a known-working lamp into the same outlet  
and verify it works. Properly functioning AC power is required in order to operate the amplifier.  
• Check each end of the amplifier’s power cord. The AC plug or IEC-type connector needs to be properly inserted. Inspect the cord  
for damage. If any damage is found, replace the cord immediately.  
• Unplug any device connected to the amplifiers Remote Trigger jacks. If the amplifier now turns on and off normally, the problem  
is with the cables or equipment that was connected to the Remote Trigger jacks.  
Signal LED’s not responding to input signal level (not lighting)-  
• If the green Power indicator LED is lit, but the signal LEDs do not light up at all, check the input. Make sure the signal source is  
working and try another input cable. Connect the source to another channel or amplifier and verify that it is working properly.  
Connect a known good signal source to the amplifier to verify the amplifier is working properly.  
• If you are using the XLR or RCA jacks, be sure the connectors are fully inserted at both ends of all interconnecting cables.  
• If using the DataPort inputs, make sure connections are tight and that the software configuration in the upstream device (if  
applicable) is not muting the signal.  
Signal LEDs responding to signal level but no output-  
• If the green signal LED indicators are lighting normally, the fault is somewhere between the amp and the speakers. Check the  
speaker wiring for proper connection at each end and for any damage or breaks. Try another speaker and cable. If your system has  
multiple speakers connected in series, any one speaker failure will cause all other speakers (in the same series circuit) to lose  
their signal.  
Clip LED flashing, but no output-  
• If the red Clip indicator flashes when signal is applied, the amplifier output may be shorted. Disconnect the speaker cables from  
the amplifier. If the clip indicator no longer illuminates, the problem is in the speaker cable or the speaker.  
• Connect the speaker cables to the amplifier, but not the speakers. Make certain the conductors cannot touch at the uncon-  
nected speaker-end of the cables. If the Clip indicator no longer illuminates, the problem is most likely in the speaker.  
• Check that the speaker cable connections are tight and properly terminated at each end. Check the speaker cables for stray  
strands or breaks in the insulation. Trim off all loose strands of wire and insulate any exposed wire with electrical tape. All  
connections should be made with great care and all wire terminations should be carefully checked to ensure quality workmanship.  
The Clip LEDs are fully illuminated-  
• The amplifier is in Thermal Protection mode. Let the amplifier cool down. Leave the Power on so the fan will cool the amplifier.  
Check for proper ventilation. If the fan isn't running at all, the amplifier requires servicing.  
• If normal operation does not resume after letting amplifier cool down, the amplifier requires service.  
The amplifier “cuts-out” when I really crank it up (intermittent operation)-  
• Make sure the AC power source is rated for the required current! Avoid using extension cords! If required, use only the shortest  
possible 10-gauge heavy-duty extension cords.  
• If the AC power source is “sagging” (or drooping) under heavy load, the circuit is overloaded or has other fundamental prob-  
lems. Use another circuit or have the circuit checked by a licensed, professional electrician.  
34  
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TROUBLESHOOTING  
I am using the amp for a subwoofer application and it sounds “rubbery”, what’s up?-  
• Verify that the Clip Limiters are OFF. Why? The Clip Limiter is set to respond as quickly as possible after clipping is detected. On  
low frequency material, this may be perceived as a “rubbery” effect. It may be preferable to turn Clip Limiting off, and let the amp  
clip occasionally, especially if the speakers are robust.  
• If your subwoofer is rated for frequencies below 50 or 20 hertz, set the Low Frequency (LF) filters accordingly.  
No channel separation-  
• Check the mode switch settings on the back of the amplifier. If the mode switches are set for PARALLEL mode, there will be no  
channel separation. The mode switches must be set for STEREO for each channel to operate independently.  
• Make sure other equipment in the signal path to the amplifier, such as DSP, mixers, preamps, etc., is set for stereo, not mono.  
The output sounds distorted-  
• Indication: Clip indicator flashing- If the red clip indicator flashes before the signal indicator does, the load impedance is  
abnormally low or shorted. Unplug each speaker one-by-one at the amplifier. If the clip LED goes out when you disconnect a cable,  
then that cable or speaker is shorted. Try another cable and speaker to locate and/or remove the fault.  
• Indication: Clip Indicator not flashing- This could be caused by a faulty speaker or loose connection. Check the wiring and try  
another speaker. If not the speaker or connections, see next item to test for signal source distortion.  
• The signal source may be clipping. Keep the amplifier gain controls at least halfway (19 dB or so) up so that the source does not  
have to be overdriven. Reduce signal levels upstream of the amplifier to identify overdrive source.  
There seems to be a lot of “hiss” noise on the outputs-  
• Unplug the input cables to the amplifier. If the hiss goes away, then the problem is with the equipment or cables leading to the  
amplifier.  
• If the hiss is present with no audio input cables connected, check that the AC line cord is properly grounded at its connection to  
the line. If the ground connection is OK and the hiss continues with no input cables connected, then the amplifier requires  
servicing.  
• To keep the normal noise floor low, operate the primary signal source at full level, without clipping, and avoid boosting the  
signal further between the source and the amplifier.  
The output has a “hum” noise-  
• Use a common AC ground connection for all audio equipment.  
• Check the input cables for broken ground (shield) connection.  
• Use balanced connections where possible for the entire signal chain.  
• The design of the amplifier eliminates internal hum fields, but external transformers or other magnetic devices may cause hum.  
Move cabling and signal sources to identify "hot spots" in the system; then avoid those spots. Cables with faulty shielding are a  
common entry point for hum. Use top quality cabling. Another common source of magnetic fields are “wall warts” or pluggable  
transformers; keep input wiring away from them.  
• Troubleshoot the system for ground-loop problems. Any identified ground loop must be broken using audio signal isolation. Do  
not “lift” or break AC power grounds under any circumstance as safety of the system will be compromised.  
35  
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SPECIFICATIONS- SRA Series  
SRA1222  
SRA2422  
SRA3622  
Output Power:  
(watts per channel, stereo/parallel mode)  
8 ohms, 20Hz to 20kHz, 0.03% THD  
4 ohms, 20Hz to 20kHz, 0.05% THD  
2 ohms, 1kHz, 1.0% THD  
200  
350  
600  
425  
725  
1200  
725  
1100  
1800  
Output Power:  
(watts, bridge mode)  
8 ohms, 20Hz to 20kHz, 0.10% THD  
4 ohms, 20Hz to 20kHz, 0.10% THD  
750  
1200  
1550  
2400  
2400  
3600  
Output circuitry:  
class AB  
<0.01%  
2-tier class H  
<0.02%  
2-tier class H  
<0.02%  
Distortion (SMPTE-IM):  
Distortion (4 and 8 ohm, typical):  
20 Hz to 20 kHz: 10 dB below rated power  
1 kHz and below: at full rated power  
<0.02%  
<0.01%  
<0.02%  
<0.01%  
<0.02%  
<0.01%  
Input Sensitivity:  
(for rated power into 8 ohm load)  
1.43V  
1.35V  
2.12V  
1.92V  
2.71V  
2.38V  
Input Sensitivity:  
(for rated power into 4 ohm load)  
Power requirements:  
5.6 amps  
5.0 amps  
8.0 amps  
(pink noise, 1/8 rated power)  
at 4 ohms/ch.  
at 8 ohms/ch.  
at 8 ohms/ch.  
Slew Rate:  
20V/uS  
20V/uS  
20V/uS  
Frequency response, all models:  
(LF filter switched off)  
20 Hz to 20 kHz, 0.2 dB  
8 Hz to 50 kHz, +0, -3 dB  
Damping factor @ 1 kHz and below:  
Noise, all models, 20 Hz–20 kHz:  
>500  
-107 dB  
Specifications subject to change without notice!  
36  
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SPECIFICATIONS- SRA Series  
ALL MODELS  
Voltage gain:  
28× (29 dB)  
Controls:  
Front-  
Rear-  
AC switch, Recessed Ch. 1 and Ch. 2 gain knobs  
DIP switch (Ch. 1: clip limiter on/off, LF filter on/off,  
LF filter freq select—20 or 50 Hz; Ch. 2: clip limiter on/off, LF filter on/off,  
LF filter freq select—20 or 50 Hz; inputs parallel or stereo; bridge mode)  
Connectors:  
Input-  
gold-plated RCA, 3-pin XLR (1 each per channel)  
Neutrik Speakon (1 per channel) and safety-shrouded binding posts  
two 3.5 mm jacks in parallel (12V or switch remote on/off trigger)  
HD-15 for QSC DSP accessory  
Output-  
Remote-  
DataPort-  
Input impedance:  
Indicators:  
XLR-  
RCA-  
10k ohms unbalanced, 20k ohms balanced  
10k ohms unbalanced  
Clip-  
Signal (-30 dB)-  
Power-  
red LED (1 per channel)  
green LED (1 per channel)  
green LED  
Cooling:  
ultra-quiet variable-speed fan, rear-to-front air flow  
Amplifier Protection:  
Full short circuit, open circuit, thermal, ultrasonic, and RF  
protection. Stable into reactive or mismatched loads.  
Load protection:  
Dimensions:  
on/off muting, DC-fault power supply shutdown  
Width-  
483 mm (19.0”) with rack mount ears installed  
445 mm (17.5”) without rack mount ears  
Height-  
Depth-  
89 mm (3.5”) 2 rack units  
394 mm (15.5”) overall  
381 mm (15.0”) from front of rack rail to tip of rear support chassis tab  
Weight:  
10 kg (22 lb.) net  
Available Finish:  
black chassis with black front panel/inserts or black chassis with silver front panel/inserts  
Specifications subject to change without notice!  
37  
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WARRANTY INFORMATION & HOW TO CONTACT QSC  
(USA only; other countries, see your dealer or distributor)  
WARRANTY  
Disclaimer  
QSC Audio Products, Inc. is not liable for any damage to speakers, or any other equipment that is caused by  
negligence or improper installation and/or use of this amplifier product.  
QSC Audio Products 3 Year Limited Warranty  
QSC Audio Products, Inc. (“QSC”) guarantees its products to be free from defective material and / or work-  
manship for a period of three (3) years from date of sale, and will replace defective parts and repair mal-  
functioning products under this warranty when the defect occurs under normal installation and use -  
provided the unit is returned to our factory or one of our authorized service stations via pre-paid transporta-  
tion with a copy of proof of purchase (i.e., sales receipt). This warranty provides that the examination of the  
return product must indicate, in our judgment, a manufacturing defect. This warranty does not extend to any  
product which has been subjected to misuse, neglect, accident, improper installation, or where the date  
code has been removed or defaced. QSC shall not be liable for incidental and/or consequential  
damages. This warranty gives you specific legal rights. This limited warranty is freely transferable during  
the term of the warranty period.  
Customer may have additional rights, which vary from state to state.  
In the event that this product was manufactured for export and sale outside of the United States or its  
territories, then this limited warranty shall not apply. Removal of the serial number on this product, or  
purchase of this product from an unauthorized dealer, will void this limited warranty.  
Periodically, this warranty is updated. To obtain the most recent version of QSCs warranty statement,  
HOW TO CONTACT QSC AUDIO PRODUCTS  
Mailing Address:  
QSC Audio Products, Inc.  
1675 MacArthur Boulevard  
Costa Mesa, CA 92626-1468 USA  
Telephone Numbers:  
Main Number  
Sales  
(714) 754-6175  
(714) 957-7100  
(800) 854-4079  
(714) 957-7150  
(800) 772-2834  
Sales & Marketing  
Technical Services Group  
(toll-free in U.S.A. only)  
(toll-free in U.S.A. only)  
Facsimile Numbers:  
Sales & Marketing FAX  
Technical Services Group FAX  
(714) 754-6174  
(714) 754-6173  
World Wide Web:  
E-mail:  
38  
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QSC Audio Products, Inc. 1675 MacArthur Boulevard Costa Mesa, California 92626 USA  
“QSC” and the QSC logo are registered with the U.S. Patent and Trademark Office.  
©2002 QSC Audio Products, Inc.  
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