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LT/ST Power Amplifier
Owner’s Manual
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important precautions Service Information Save the carton and packing materials! Do not run the output of any ampli- 1 ¡ Should you ever need to ship the unit, fier channel back into another Do not remove the cover! use only the original factory packing. channel’s input. Removing the cover will expose you to potentially dangerous voltages.There are For replacement packaging,call Crest Audio’s Do not parallel- or series-connect no user serviceable parts inside. Customer Service Department direct
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table of contents p.2 how to use this manual 1 p.3 introduction p.5 installation 2 unpacking mounting cooling and ventilation powering maintenance p.9 features overview 3 front panel rear panel p.15 operation modes 4 stereo contents parallel bridged p.17 connections 5 input output p.21 safety 6 tourclass protection precautions user responsibility p.25 service and support 7 support contact us registration p.27 specifications a appendices p.28 block diagram b p.29 wire gauge ch
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LT / ST owner’s manual how to use this manual 1 conventions terms official Crest Audio features and each indicator or control on the amplifier will appear as: terms actions specific actions or selections the user can execute will appear as: actions tasks are broken down into steps 1 2 3 warnings Procedures not to attempt. Issues or hazards to keep in mind when operating the equipment. indicators What to look for on ® the equipment display. Alerts, indicators, or prompts that may appear. tips
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introduction 1 welcome Congratulations on your purchase of a new LT / ST Series professional power amplifier and thank you for your con- fidence in Crest Audio products.You are among the growing number of audio professionals who have made Crest Audio one of the world’s leading suppliers of professional and commercial/industrial audio systems. For your safety, please read the Important Precautions section before installing and operating the amplifier.The Crest Audio LT and ST Series amplifiers ar
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installation 2 / what to do with the shipping carton unpacking / proper rack-mounting technique / mounting keeping the amplifier cooled / required AC line voltages cooling and / routine maintenance practices ventilation powering maintenance p.5
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installation LT / ST owner’s manual 2 unpacking Please inspect the amplifier carefully immediately after unpacking. If you find any dam- For replacement age, notify your supplier/dealer immediately. Only the shipper may file a damage claim packaging, call Crest with the carrier for damage incurred during shipping. Be sure to save the carton and Audio’s all packing materials for the carrier’s inspection. Customer Service Department directly. If the packing materials are in good condition, pleas
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installation 2 cooling and ventilation LT / ST amplifiers use a forced air cooling system to maintain a low,even operating tem- perature. Make certain that there is enough space around the front and rear of the amplifier to allow the Air is drawn in by a DC fan on the rear panel, flows through the cooling fins and then heated air to escape. When mounting in a rack, exhausts through the front panel vent. try to avoid using doors or covers on the front Heat sink temperature is monitored and contro
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features overview 3 / location of connectors and controls front panel / legend of panel symbols rear panel p.9
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features overview 3 LT / ST owner’s manual LT / ST shown 2 1 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 p.10
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features overview 3 front panel Rack Mounting Ears 1 Two front-panel mounting holes are provided on each mounting ear. Channel Level attenuators 2 Two input attenuators adjust level for their respective amplifier channels. In Bridged Mono and Parallel modes, the channel A attenuator controls overall signal level (see rear panel mode switch description). Protect 3 This Red LED indicates that the amp channel is in Protect mode. During Power up, the amp briefly goes into protect mode in order to
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LT / ST shown 2 3 4 5 6 1 7 rear panel legend rear panel input connection IEC power connector 1 XLR connector polarity Accepts a standard IEC terminated power cable TRS connector polarity Breaker 2 bridged mono mode Resettable circuit breaker - no fuses are used. Breaker can trip due to parallel mode a power surge or over-voltage condition. If it trips once, reset it. If it continues to trip, the amplifier may need servicing. stereo mode Fan 3 chassis ground lifted-position The fan operat
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features overview 3 rear panel Output connections 4 Speakers can be connected via the high current binding posts and the industry-standard Speakon (NL-4) connectors. Binding posts: One pair (Red- hot, Black- ground) per channel. Speakons - One connector for each channel. In Bridged Mono mode, the Speakon connector for Channel A is used exclusively Never connect a hot (see Operation Modes). (red) output to ground or to another hot (red) output! Ground lift switch 5 The recessed two-position grou
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operation modes 4 / choosing the appropriate mode stereo / switching between operation modes / special considerations when using bridged mode parallel bridged p.15
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operation modes 4 LT / ST owner’s manual mode selection The three-position,recessed Mode Select switch (located on the rear panel) configures the amplifier for Stereo, Parallel or Bridged mode. Amplifiers are factory-configured for Stereo mode. Shut the amp off before changing modes. stereo In Stereo mode,both channels operate independently,with their input atten- uators controlling their respective levels.Signal at Channel A’s input produces output at Channel A’s output,while signal at Chann
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connections 5 / speakon proper wiring schemes for connectors: input binding post XLR 1/4” TRS / correct signal paths: stereo, parallel and bridged output Phoenix 3 pin p.17
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connections LT / ST owner’s manual 5 inputs LT / ST amplifiers are configured standard with pin 2 hot on XLR inputs. female XLR TRS pinouts 3-pin Phoenix (view of connector on rear of amp) In + In - Com outputs Speakers are connected using the high-current five-way binding posts or speakon connectors, or both. Very high current is available at the outputs. stereo/parallel bridged mono Please connect your output cable to the + and - terminals of each sec- tion precisely as shown. Speaker +
