User manual CREST AUDIO ST SPECIFICATIONS

[. . . ] LT/ST Power Amplifier Owner's Manual important precautions 1 Save the carton and packing materials!Should you ever need to ship the unit, use only the original factory packing. For replacement packaging, call Crest Audio's Customer Service Department directly. ¡ Do not run the output of any amplifier channel back into another channel's input. Do not parallel- or series-connect an amplifier output with any other amplifier output. [. . . ] Air is drawn in by a DC fan on the rear panel, flows through the cooling fins and then exhausts through the front panel vent. Heat sink temperature is monitored and controls the variable speed fan. Fan speed increases only as required, keeping fan noise to a minimum. 2 a Make certain that there is enough space around the front and rear of the amplifier to allow the heated air to escape. When mounting in a rack, try to avoid using doors or covers on the front and rear of the enclosure; the exhaust air must not be impeded suggestion In racks with closed backs allow at least one standard-rack-space opening for every four amps. If the heat sink surpasses its maximum allowed temperature, the thermal protection circuit will activate and open the output relays allowing the amplifier to cool to a safe temperature. To continue using the amp, it must be reset by turning the power off and then turning it back on again. Thermal protect activation only occurs under extreme thermal conditions and is not part of normal operation. powering Unless otherwise specified when ordered, LT / ST amplifiers are supplied factory set to following voltage options : Option 1 US domestic nominal 120Vac 60Hz for rated power output (safe operating range 100 - 132Vac ) Option 2 export models nominal 230Vac 50Hz for rated power output (safe operating range 200 - 264Vac ) note Due to the nature of the switching power supply in the ST, 50 - 60Hz operation is acceptable for both options. maintenance LT / ST amplifiers require no routine maintenance. Cool air flows over the heat sink and exhausts through the front grill. Make sure this outlet remains clear to allow unrestricted airflow. 9 Power switch This switch turns the amp on and off. If the amp doesn't turn on when the switch is in the ON position, check the circuit breaker on the rear panel. p. 11 LT / ST shown 2 3 4 5 6 1 7 rear panel legend rear panel 1 IEC power connector Accepts a standard IEC terminated power cable input connection XLR connector polarity TRS connector polarity bridged mono mode parallel mode stereo mode chassis ground lifted-position chassis ground grounded-position output connection speakon output channel A stereo/parallel channel B stereo/parallel bridged mono five-way binding post channel A stereo/parallel bridged mono channel B stereo/parallel 2 Breaker Resettable circuit breaker - no fuses are used. Breaker can trip due to a power surge or over-voltage condition. If it continues to trip, the amplifier may need servicing. 3 Fan The fan operates continuously while the amp is on. An internal temperature sensor increases the speed of the fan during high temperature conditions. Air enters through the rear of the amp and exits through the front grill. Be sure to allow adequate air flow from the rear of the rack the amp is mounted in. p. 12 features overview rear panel 4 Output connections 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 (see Operation Modes). Never connect a hot (red) output to ground or to another hot (red) output! 3 a 5 Ground lift switch The recessed two-position ground lift switch is used to isolate the amp's signal ground from the chassis/AC ground. The factory default setting is to the right, Grounded. To lift, or disconnect the signal ground from the chassis/AC ground, slide the switch to the left. In situations where chassis ground must be lifted, use this switch never lift the ground prong on the AC connector. 6 Input connections Input signals can be connected to the amp via the Phoenix connectors, the 1/4" TRS connectors and the Female XLR (pin 2 hot) connectors. Input sensitivity is . 775v (0 dBv) for full rated output power. See Connections In situations where an UNBALANCED signal is fed to the amp, it's important to ground the unused input. [. . . ] In addition, if extreme and sustained low impedance is encountered, the amplifier's output relay will open. AutoRamp Auto Ramp operates every time the amplifier is turned on or is reactivated after a protect condition is corrected. This exclusive Crest Audio feature gradually increases gain to the attenuator setting avoiding unnecessary stress on the loudspeakers. Thermal Protect Abnormally high heat sink temperatures will engage the Protect circuit and disconnects the output relays. During this time the Prot LEDs will light red. The cooling fan will continue running at high speed. [. . . ]