User manual CREST AUDIO PRO 200 SERIES

[. . . ] PRO 200 Series Amplifier Owner's Manual Intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. Intended to alert the user of the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product. CAUTION: Risk of electrical shock -- DO NOT OPEN!CAUTION: To reduce the risk of electric shock, do not remove cover. [. . . ] Make sure this outlet remains clear to allow unrestricted airflow. 9 AC Power Switch/Circuit Breaker Pro 200 Series amplifiers have a combination AC switch/circuit breaker on the front panel. If the switch shuts off during normal use, push it back to the ON position once. If it will not stay on, the amplifier needs servicing. p. 9 3 Features Overview Rear Panel 12 4 6 7 3 5 Rear Panel Legend Rear Panel 1 Input Connectors Input signals can be connected to the amp via the Neutrik Combicon connectors, using either a TRS or XLR connector. Input sensitivity is . 775v (0 dBv) for full rated output power. See -- Input Connections in Chapter 5 for more information. Input Connection Output Connection Channel A stereo/parallel Bridged mono Channel B stereo/parallel Input Connector Polarity Table Speakon Output Polarity Table 2 Gain Select Switch The rear panel Gain Select switch determines whether the amplifier has an overall gain of 40x (32 dB) or 20x (26 dB). The OUT position will select x40 The IN position will select x20. 3 Mode Select Switch The rear panel Mode Select Switch determines whether the amplifier is in stereo, parallel or bridged mono mode. Do not operate the Mode Select Switch with the amplifier on. See -- Chapter 4 for more information on operation modes. Do not adjust the mode selection switch while the amplifier is turned-on. a p. 10 Features Overview Rear Panel cont. 4 Cooling Fans The cooling fans operate continuously while the amplifier is on. An internal temperature sensor increases the speed of the fans during high temperature conditions. Air enters through the rear and exits through the front grille. Be sure to allow adequate air flow from the rear of the rack in which the amp is mounted. 3 5 Binding Post Output Connectors Speakers can be connected via the high current binding posts. One pair of posts is provided (Red- hot, Black- ground) for each channel. See -- Output Connections in chapter 7 for information on Bridged Mono operation using Binding Posts. Never connect a hot (red) output to ground or to another hot (red) output! a 6 Speakon Output Connectors Speakers can also be connected via industry-standard Speakon (NL4) connectors. One connector is provided for each channel. In Bridged Mono mode, the Speakon connector for Channel A is used exclusively Note -- Both Binding Post and Speakon output connectors may be used at the same time. Both sets are are parallel to each other, so if you use them together be sure calculate the total impedance for each channel. For example: If you connect a 4 ohm load to the binding posts on channel A, and another 4 ohm load via the Speakon connector on channel A, the total impedance for channel A will be 2 ohms, not 4. In situations where an UNBALANCED signal is fed to the amp, it's important to ground the unused input. If the inverting (-) input of an amp channel is left floating, the gain will drop by 3 dB. For more information about this, ask your dealer or contact Crest Audio Technical Support directly. + 7 IEC power connector Accepts a standard IEC terminated power cable See -- Connecting Power in Chapter 5. p. 11 Operation Modes 4 / Choosing the appropriate mode Switching between operation modes Special considerations when using bridged mode Stereo / / Parallel Bridged p. 13 4 Operation Modes Mode Selection The rear panel Mode Select Switch determines whether the amplifier is in stereo, parallel or bridged mono mode. Do not operate the Mode Select Switch with the amplifier on. [. . . ] While the speakers are disconnected, the Auto Ramp circuit fully attenuates the signal. After the output relay closes, the signal slowly and gradually raises up to its set level. The Auto Ramp Signal Control circuit has some important advantages over the conventional instant-on circuits: 1. If a signal is present during power-up or when coming out of a protect mode, the speakers are spared a sudden, potentially damaging burst of audio power. Because the gain is reduced until after the output relay closes, no arcing occurs at the contacts, thereby extending their useful life. p. [. . . ]