User manual CREST AUDIO PRO II SERIES

[. . . ] owner's manual 8002 power amplifier Professional Power Amplifier 8002 ACL Signal Status -6 -10 -15 -30 -80 -1 ØdB -3 -10 -15 -30 -80 ØdB -1 -6 -3 Ch A Ch B 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. [. . . ] There are no user-serviceable parts or adjustments that require opening the power amplifier. Cover removal exposes the risk of shock, so refer all servicing to qualified service technicians authorized by Crest Audio. a p. 10 features overview 3 / location of connectors and controls legend of panel symbols front panel / rear panel p. 11 3 features overview 8002 shown Pro II owner's manual 1 2 3 Professional Power Amplifier 4 5 67 8 8002 ACL Signal Status -6 -10 -15 -30 -80 -1 ØdB -3 -10 -15 -30 -80 ØdB -1 -6 -3 Ch A Ch B p. Using cables terminated with Speakon connectors, attach to both the channel A and channel B connectors for Stereo or Parallel mode, or to the Bridged mode connector/s for Bridged Mono mode. see--operation modes rear panel legend input connection 1 3- 2+ XLR TRS connector polarity connector polarity Ø 40x 20x dBu XLR Pin + 2 Mode Selection Switch This recessed, three-position switch configures the amplifier for Stereo, Parallel or Bridged Mono mode operation. Amplifiers are factory-configured for Stereo mode. see--operation modes A B Do not adjust the mode selection switch while the amplifier is turned-on. a + + + B p. 14 + A AB A AB AB AB GAIN bridged mono mode parallel mode stereo mode chassis ground lifted-position chassis ground grounded-position gain select XLR pin 2/3 hot (+) output connection speakon output channel A stereo/parallel channel B stereo/parallel Ø 40x 20x dBu 2 3 GAIN A B bridged mono five-way binding post A XLR Pin + channel A stereo/parallel A B 2 3 bridged mono channel B stereo/parallel features overview rear panel 3 Female Balanced XLR Input Connectors 4 Male Balanced XLR Input Connectors These connectors accept input signals on balanced male and female XLR input plugs. Connectors for each channel are in parallel; any unused XLR connectors may be used for daisy-chaining input connections to other amplifiers. In Parallel and Bridge Mono mode a signal applied to channel A's input connectors will appear also at channel B's. Never connect a hot (red) output to ground or to another hot (red) output! 3 a 5 Input Sensitivity/Gain Switch The Pro II Series amplifiers come standard set to x40 gain. The Input Sensitivity/Gain switch allows the user to select either . 775 (0dB) sensitivity, x40, or x20 gain. 6 Fan Inlet Ports and Filters Cooling air enters the amplifier through the fan inlet ports located on the rear of the amplifier chassis. Be sure not to block these ports when installing the amplifier or other associated equipment. Air must flow unimpeded. Fan filters (removable without tools) are provided to minimize entry of dust and dirt. 7 Input XLR Polarity Switch Pro II Series amplifiers are supplied standard with the XLR configured as Pin 2 hot (+). Use the XLR polarity switch to change this setting to Pin 3 hot (+) if desired. 8 Signal Ground-Lift Switch The recessed signal ground-lift switch electrically connects signal ground to the chassis/AC ground. This switch is factory-set to the ground position (bottom). The top position lifts the amplifier's signal ground. In a properly designed system (for safety purposes and to minimize noise), amplifiers should be connected to ground through the AC line cord. Whenever possible, the signal source equipment should share the same AC ground as the amplifier. In some cases this may not be possible, and a ground loop results. If this happens, the first step is to move the ground-lift switch to the lifted position (top). In this position, the signal ground is lifted and completely isolated from the chassis/AC ground. Do not change the switch to the lifted position if the amplifier and the signal source equipment are on the same AC ground. Should the ground loop problem persist after the ground-lift switch has been set to the lifted position, then the shield on balanced input lines should be grounded at one end only (usually the signal source). p. 16 operation modes 4 / choosing the appropriate mode switching between operation modes keeping the amplifier cooled special considerations when using bridged mode stereo / / parallel / bridged p. 17 4 operation modes 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. Pro II owner's manual stereo In Stereo mode, both channels operate independently, with their input attenuators controlling their respective levels. Signal at Channel A's input produces output at Channel A's output, while signal at Channel B's input produces output at Channel B's output. Recommended minimum nominal load impedance for stereo operation is 2 ohms per channel. Either the male or female XLR inputs may be used. parallel When set to Parallel mode, a signal applied to Channel A's input will be amplified and appear at outputs for both Channels A and B. [. . . ] Like ACL, the IGM circuit is inaudible in normal use. 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 Abnormally high heat sink temperatures will engage the Protect circuit for the overheating channel only. (An output relay disconnects the loudspeakers until nominal temperature range is restored. ) During this time, the Status LED will light red. [. . . ]