ISA Series Installed Sound Amplifiers n n n n n n ISA 300T ISA 500T ISA 800T ISA 280 ISA 450 ISA 750 User Manual ISA Audio Power Amplifiers *TD-000093-00* TD-000093-00 rev.
IMPORTANT SAFETY PRECAUTIONS & EXPLANATION OF SYMBOLS CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE THE COVER. NO USERSERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.
TABLE OF CONTENTS INTRODUCTION: ISA Series Overview .......................................................................................4 Front Panel Illustration .........................................................................................4 Rear Panel Illustrations ........................................................................................5 FEATURES & SETUP : Power Switch ............................................................................................
INTRODUCTION- INTRODUCTION AND FRONT PANEL ILLUSTRATION Thank you for the purchase of your new ISA amplifier. To get the most out of your amplifier, review this manual carefully. The installation, connection and operation sections provide useful guidelines to get you up and running quickly and correctly. For those systems with QSC DataPort accessories (DSP, crossovers & filters, remote cinema monitoring) a DataPort V2 (version 2) is included on all ISA models.
1. Gain Controls 2. Terminal Block Inputs 3. DataPort V2 Connector 4.
FEATURES & SETUP- POWER SWITCH, COOLING AIR VENTS The front panel of ISA series amplifiers is tailored for installed sound. The power switch is the only front panel control; gain controls are located on the rear panel to minimize control tampering. LED indicators are provided for power, input signal and to warn of clipping. The power switch is a rocker-type switch. To turn the amplifier on, push in on the top portion of the switch. To turn the amplifier off, push in on the bottom portion of the switch.
FEATURES & SETUP- LED INDICATORS POWER: green LED that illuminates when the power switch is set to the on position and AC power is present at the IEC cord receptacle. Normal indication: at power-on the LED will illuminate at half-brightness for 2-3 seconds, then it illuminates to full-brightness. SIGNAL: green LED that lights up when the input signal is strong enough to drive the output to about -40 dB from rated 8-ohm power. Normal indication: varying brightness corresponding to strength of input signal.
FEATURES & SETUP- GAIN CONTROLS & INPUT JACKS GAIN CONTROLSThe Gain controls are located on the rear panel to minimize control tampering after installation. When viewing the amplifier from the rear, they are on the left end, top and bottom, as shown in the illustration to the right. The Gain controls are detented (11 steps) for repeatable adjustment. Surrounding the Gain control, the power attenuation level is shown in dB.
FEATURES & SETUP- DATAPORT V2 DATAPORT V2What It Is- The DataPort V2 is used for connection to optional QSC DataPort accessories. DataPort accessory devices can provide remote cinema monitoring, DSP, filter and crossover functions. The “V2” DataPort connection is a “version-2” of QSC’s original DataPort. It has a reduced feature set from the original, while maintaining essential amplifier monitoring capability. It does not supply +15 VDC power required by some DataPort accessories.
FEATURES & SETUP- STEREO & PARALLEL OPERATING MODES STEREO: Each input signal is sent to its respective channel. Each channel has independent low-frequency (subaudio) filtering, clip limiting, gain control, and output connection. When to use STEREO input configuration: Use stereo mode for stereo sources (L-R inputs) and any other situation that requires each channel to be completely separate from the other. How to use STEREO mode: 1- Set the DIP switches for stereo mode operation (see facing page).
FEATURES & SETUP- STEREO & PARALLEL MODE DIP SWITCH SETTINGS SETTING THE DIP SWITCHES FOR STEREO OR PARALLEL MODE- “non-T” models ISA 280, ISA 450, ISA 750: Refer to the switch setting keys for each mode, to the right. These keys are printed on the amplifier’s rear panel for easy reference when you are behind the equipment rack. STEREO Mode- Set switch #4, 5, 6 and #7 to the left. PARALLEL Mode- Set switch #4 and #5 to the right; set switch #6 and #7 to the left.
FEATURES & SETUP- BRIDGE OPERATING MODE & DIP SWITCH SETTINGS BRIDGE MODE OPERATIONNote that speaker connection for bridge mono mode is different than other modes. See section on Connections: Outputs for proper bridge mode output connections.
FEATURES & SETUP- LOW FREQUENCY FILTER & DIP SWITCH SETTINGS Generally, match the frequency selection to your speaker’s low frequency capability. This improves speaker performance by limiting subaudio cone movement, making more power available for the speaker’s rated frequency range. Unless you already have filtering in the signal path preceeding the amplifier, use the low frequency filter to protect your speakers from cone over-excursion caused by frequencies below the speaker’s limits.
FEATURES & SETUP- CLIP LIMITER & DIP SWITCH SETTINGS CAUTION: Clip limiting reduces extreme overdrive peaks, allowing a higher average signal level without audible distortion. However, 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.
INSTALLATION: RACK MOUNTING AND MOUNTING DIMENSIONS NOTE: Rack mounting of amplifier is optional. Securing the Front Ears to the Rack Rails Use four screws and washers when mounting the ISA amplifier to the front rails. Support the weight of the amplifier while securing it to the rails to avoid bending or distorting the front rack mount ears. Amplifiers are inherently heavy. It is highly recommended that you have an assistant support the amplifier during rack installation to avoid injury.
INSTALLATION: COOLING REQUIREMENTS & AC MAINS FAN COOLINGAll QSC amplifiers draw cool air into the rear of the amplifier and exhaust the hot air from the front. This is done so that the equipment in the rack stays as cool as possible. This method of cooling also gives the technician “direct” air temperature feedback at the front of the rack, where it is the most convenient. The front panel’s temperature is an accurate indicator of “how hard” the amplifier is working.
CONNECTIONS: INPUTS- XLR & TERMINAL BLOCK Each channel has active balanced "Euro-style" terminal block and XLR input jacks wired in parallel. The input impedance is 20k ohm balanced or 10 k ohm unbalanced. Unused input jacks may be daisy chained to additional amplifiers. Balanced connection is recommended. Balanced signals are less prone to AC hum and other electrical noise. Unbalanced signals can be suitable for short cable runs.
CONNECTIONS: INPUTS- DATAPORT V2 The ISA series of amplifiers come with a DataPort V2 connector that may be used for connecting to accessory QSC DataPort devices. The V2 (or version 2) DataPort does not have the full capability of the standard DataPort. The DataPort V2 must be connected to a QSC DataPort product with a QSC DataPort cable; similar looking computer data cables will not work and could damage your QSC equipment. The DataPort V2 connection will supply the input signals to the amplifier.
CONNECTIONS: OUTPUTS- USING THE SCREW TERMINAL CONNECTIONS GENERALThe screw terminal output connections are protected by a hinged plastic cover. To make connections to the screw terminals, you will need to swing the cover door open. Gently pry the cover with your finger tips on the side that has the wire openings. After the door is open, loosen the screws for the terminals you are planning to use. Do this by rotating the screw counter-clockwise with an appropriate screwdriver.
CONNECTIONS: OUTPUTS- DIRECT LOW IMPEDANCE (LO-Z) ISA amplifiers are equipped with screw-terminal output connections. The ISA 280, ISA 450 and ISA 750 provide low-impedance outputs only (2 to 16 ohms) while the ISA 300T, ISA 500T and ISA 800T provide both low-impedance and high-impedance (25V, 70V and 100V) outputs. When selecting speaker cable (wire), always use the largest wire size and shortest length of wire practical for any given installation.
CONNECTIONS: OUTPUTS- DISTRIBUTED HIGH IMPEDANCE (HI-Z) , STEREO & PARALLEL
CONNECTIONS: OUTPUTS- DISTRIBUTED HIGH IMPEDANCE (HI-Z) , BRIDGE MODE OUTPUT TERMINAL SAFETY WARNING! Do not touch output terminals while amplifier power is on. Make all connections with amplifier turned off.
CONNECTIONS: POWER SHARING BETWEEN HIGH & LOW IMPEDANCE OUTPUTS The ISA 300T, ISA 500T and ISA 800T models are equipped with autotransformer-coupled, high impedance (High-Z) outputs. They are also equipped with low impedance (LowZ) “direct” outputs. The high impedance outputs are not isolated. The unique feature of the “T” model outputs is that you can connect loads to the high impedance AND low impedance outputs for maximum system flexibility.
CONNECTIONS: SECURING OUTPUT WIRING TO CHASSIS
OPERATION: AC POWER SWITCH, LED INDICATORS, GAIN CONTROLS AC POWER SWITCH Before applying power, check all connections and turn down the gain controls. When the AC power is switched on, the power indicator LED will light at half brightness and the fan will start. The outputs are muted. Then the power indicator fully illuminates and the amplifier unmutes. The clip and signal LEDs will flash briefly. When the clip LEDs go out, the amplifier is ready.
APPLICATIONS: GENERAL APPLICATION INFORMATION General ISA Application InformationThe ISA 280, ISA 450 and ISA 750 amplifiers are optimized for directly driving low impedance loads. Low impedance (Lo-Z) loads are those loads between 2 and 16 ohms. These models are not suitable for driving “constant voltage” 70V lines. These low impedance models are referred to collectively as the “non-T” models. The Lo-Z outputs will handle impedances down to 2 ohms.
APPLICATIONS: LOW FREQUENCY FILTERING & DISTRIBUTED OUTPUTS Low Frequency Filtering for 70-100V SystemsThe low frequency filtering is another difference in the characteristics of the “non-T” and the “T” amplifiers. Because transformers and other magnetic devices are prone to low frequency “misbehavior” (called saturation) , the autotransformer equipped “T” models are low frequency limited. The default low frequency roll-off is at 50 hertz; 75 hertz is the other available selection.
APPLICATIONS: DISTRIBUTED OUTPUTS 70 Volt, two-zone example: The illustration to the right shows a typical two-zone 70 volt system. When using 70 volt speaker loads, make sure that connections to the amplifier are made to the 70 volt output terminals. If using the ISA 300T, 300 watts per channel (zone) can be delivered. Make sure that the total speaker power load on each channel does not exceed 300 watts. If using the ISA 500T or ISA 800T, the perchannel power limit is 550 and 800 watts, respectively.
APPLICATIONS: MULTIPLE LOW IMPEDANCE LOADS IN SERIES (all models)
APPLICATIONS: MULTIPLE LOW IMPEDANCE LOADS IN PARALLEL (all models)
APPLICATIONS: DataPort V2 (all models) Below are listed the available QSC DataPort-compatible products that will interface with your ISA amplifier. This list will continuously change as new products become available and old products are discontinued. Always use a QSC DataPort cable for remote equipment interconnect. Computer data cables, although similar in appearance, will not function properly and may damage your equipment. Contact your QSC dealer for details and for QSC accessories.
TROUBLESHOOTING: NO SOUND Problem: NO SOUND • INDICATION: POWER LED INDICATOR NOT ILLUMINATED • Check both ends of the AC line cord for proper connection. Both ends should be fully seated in their connectors. • Check that the AC outlet works by plugging in a known-good device or by testing with a voltmeter. If too many amplifiers are used on one outlet, the building's circuit breaker may trip and shut off power.
TROUBLESHOOTING: DISTORTION, NO CHANNEL SEPARATION, HUM, HISS, FEEDBACK PROBLEM: DISTORTED SOUND Magnetic field from power supplies in equipment can induce hum into cabling that is located in the field. If hum is a problem, try relocating cabling so that is away from power supplies, transformers and other magnetic field producing devices.
SPECIFICATIONS ISA 280 ISA 450 ISA 750 OUTPUT POWER in watts FTC: 8 ohms per channel (20-20k Hz., 0.1% THD) 185 260 450 4 ohms per channel (20-20k Hz., 0.1% THD) 280 425 650 16 ohms (1 kHz., 0.1% THD, 1 channel driven) 100 140 250 8 ohms (1 kHz, 0.1% THD, 1 channel driven) 200 280 475 4 ohms (1 kHz, 0.1% THD, 1 channel driven) 300 500 750 2 ohms (1 kHz, 1% THD, both channels driven) 430 700 1200 16 ohms, 20–20k Hz, 0.1% THD 370 520 900 8 ohms (1 kHz, 0.
SPECIFICATIONS ISA 280 ISA 450 AMPLIFIER PROTECTION Full short circuit, open circuit, thermal, ultrasonic and RF protection. Stable into reactive or mismatched loads. COOLING Continuously variable speed fan; back-to-front air flow.
SPECIFICATIONS ISA 300T ISA 500T ISA 800T 8 ohms per channel (20-20k Hz., 0.1% THD) 185 260 450 4 ohms per channel (20-20k Hz., 0.1% THD) 280 425 650 16 ohms (1 kHz., 0.1% THD, 1 channel driven) 100 140 250 8 ohms (1 kHz, 0.1% THD, 1 channel driven) 200 280 475 4 ohms (1 kHz, 0.1% THD, 1 channel driven) 300 500 750 2 ohms (1 kHz, 1% THD, both channels driven) 430 700 1200 16 ohms, 20–20k Hz, 0.1% THD 370 520 900 8 ohms (1 kHz, 0.
SPECIFICATIONS ISA 300T ISA 500T AMPLIFIER PROTECTION Full short circuit, open circuit, thermal, ultrasonic and RF protection. Stable into reactive or mismatched loads. COOLING Continuously variable speed fan; back-to-front air flow.
WARRANTY INFORMATION & HOW TO CONTACT QSC WARRANTY (USA only; other countries, see your dealer or distributor) Disclaimer QSC Audio Products, Inc. is not liable for any damage to speakers, amplifiers, or any other equipment that is caused by negligence or improper installation and/or use of the ISA amplifier.
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. ©2000 QSC Audio Products, Inc.
