Gemini-XPB750-pwr-sm维修电路原理图.pdf

(1)?XPB-750/1600Power AmplifierCONTENTS:Connections & Operations:.Page 2-6Specifications:.Page 7Parts Lists:.Page 7-11PCBs:.Page 12Schematics:.Page 13-14Gemini Sound Products Corp.120 Clover Place P.O. Box 6928Edison, NJ 08818-6928732-738-9003 (Phone) 732-738-9006 (Fax)RadioFans.CN 收音机爱 好者资料库(2)1723465891011131212347589101114151719201618RadioFans.CN 收音机爱 好者资料库(3)StereoMono BridgeParallel Mono(4)Always make sure that this switch is in the correct position and thatall speaker connections have been made correctly for the mode ofoperation you wish to use before powering up the amplifier.Bridge LED (13): the bridge LED will light when you have set the rearpanel Operation Mode Switch (3) for mono bridge operation.Always make sure that this switch is in the correct position and thatall speaker connections have been made correctly for the mode ofoperation you wish to use before powering up the amplifier.Signal LED (14): the signal LEDs for each channel show when a signalis present. In Mono Bridge mode, both the channel A LED and thechannel B LED will light in unison.Clip LED (15): the amplifier has true clip LEDs to help you properlycontrol the amplifiers output and achieve undistorted sound. The clipLEDs for each channel light when your signal level is so strong thatthe distortion reaches 1% THD. The clip LED should not remainconstantly on or flash repeatedly during operation. For clean soundreproduction, the clip should only light occasionally for an instant. Ifthe LED remains on or flashes repeatedly, you will hear distortedsound that can be damaging to your speaker systems. If this occurs,reduce the signal level by lowering the input level control for thechannel that is clipping or reduce the level at the source. If the clipLED lights when no signal is present, it may indicate a RF signal onthe output which may cause damage to speakers (the RF signal willnot be audible). Please note that when you are using the amplifier inthe Mono Bridge mode, both clip LEDs of the bridged channels willoperate simultaneously.Protect LED (16): when you first turn on the amplifier, the protect LEDslight briefly during a turn-on delay which indicates that the outputsare disconnected internally. There will be an audible click when theoutputs reconnect and the protect LEDs will turn off. Otherwise, theprotect LED indicates that there is a problem either in the amplifiersexternal connections, load or temperature conditions or its internalfunctions. If one of these situations occur, the amplifier senses theproblem and automatically switches into protection mode. The LEDwill light to warn you of the trouble and the amplifier will stopworking. If this occurs, switch off the amplifier and refer to theTrouble Shooting Guide. If the protect LED remains lit when resumingamplifier operation, do not use the amplifier and contact anauthorized service technician.Level Controls (17, 18): establish the input levels required for eachchannel. Only the Channel A Level Control (17) works in MonoBridge mode.Operating InstructionsTHE AMPLIFIERS POWER MUST BE TURNED OFF WHENCHANGING MODES OF OPERATION.Stereo OperationThe unit has two channels for stereo operation. Each channelprovides a separate and discrete signal at the speaker outputsaccording to the signal received at the inputs. The following instructionsare for applications with 8 Ohm, 4 Ohm or 2 Ohm speakers of matchedpower ratings.1. With the power off, set the OPERATION MODE SWITCH (3) to theSTEREO position. When the power is on, the Mono and Bridge LEDson the front panel will not light. If these LEDs illuminate, you have theswitch in the wrong position. Correct before continuing.2. With the power off, connect your input cables to the channel A andB inputs using either the XLR INPUT JACKS (1, 5) or 1/4 INPUTJACKS (2, 4) of each channel. The other channel A and channel Binputs can be used to link to an additional amplifier.3. Connect the loudspeakers to the channel A and channel B SPEAKEROUTPUTS (9, 11). THE TOTAL SPEAKER LOAD MUST BE AT LEAST2 OHMS PER CHANNEL. If you try to operate at a lower impedance,the amplifier will go into protection mode and stop operation until youcorrect the load conditions.4. With the LEVEL CONTROLS (17, 18) of both channels set to zero(fully counterclockwise), turn the POWER SWITCH (20) on. Apply asignal to the input of the amplifier. The level of the input signal shouldConnections, Controls and IndicatorsRear Panel?Input Section:There are two parallel input connectors (one female XLR and one1/4” jack) per channel. Either can be used as an input or as a link tochain amplifiers.XLR Input Jacks (1, 5): electronically balanced inputs accept astandard XLR male connector. Pin 1 = shield/ground, pin 2 = hot orpositive (+) and pin 3 = cold or negative (-).1/4 Phone Input Jacks (2, 4): accept a balanced as well as anunbalanced line level signal. The unbalanced line uses a standardtip-sleeve connection. The tip is positive and the sleeve is negative/ground. The balanced line uses a tip-ring-sleeve connection. Tip =hot or positive (+), ring = cold or negative (-), and sleeve = shield/ground.Operation Mode Switch (3): switch is used to set the unit for Stereomode, Parallel Mono mode or Mono Bridge mode.AC Power Section:Fuse (7): replace fuse with those of proper type and rating.Signal Ground Lift Switch (8) is used to lift the balanced inputconnectors ground/shield from the amplifiers ground. When thesignal ground lifted, the sound source disconnects from theamplifiers ground preventing ground loops which can generate humand noise. See the Signal Ground Lift Switch Instructions for moredetail.AC Cord Outlet (6) (Note: 230V units only) is used to attach thepower cord to the unit.Output Section:Disconnect the unit from the AC power source before making anyconnections. Pay close attention to polarity (shown on the back of theunit) when connecting your speakers. Connecting your speakersystems using the wrong polarity will not damage your speakers, but itwill impact the quality of the sound (lack of bass and incorrect stereoimage).Speaker Outputs for 120V Unit (9, 10, 11): the speaker output jacksare 5-way binding posts that will accept a standard banana plugs,spade lugs or bare wire. Make sure that all the connections areclean when using bare wire connections. If any strands of wirefrom one connector touch the adjacent connector, the sound will bedistorted, and your amplifier will overheat and go into protectionmode.Speaker Outputs for 230V Unit (9, 10, 11): Neutrik Speakonconnectors are provided to connect speakers to the amplifier quicklyand easily. They are high current rated and provide very stable anddurable contacts. A third Speakon connector in the center isprovided to be used if the amplifier is in the Mono Bridge mode. EverySpeakon connector has pin 1- as negative and pin 1+ as positive.? ?!?#?$?%?&?$?(?)#?(?!?!?!?*? ?+?!?%? ?!?(?!?(?Front PanelPower Switch (20): turns the unit on and off.Power LED (19): the power LED lights when the power is on. If thepower LED does not light, refer to the trouble shooting guide.Mono LED (12): the mono LED will light when you have set the rearpanel Operation Mode Switch (3) for parallel mono operation.(5)be as high as you will ever need it to be. This way, it will be as highabove the amplifiers noise floor as possible, ensuring an excellentperformance and signal to noise ratio. Adjust the LEVELCONTROLS for each channel to achieve the desired maximumlistening level. Note, when the clip LEDs light, there is distortionpresent in the amplifiers output section. If a clip LED remains on orflashes repeatedly, reduce the signal level by lowering the input levelcontrol for the channel that is clipping or reduce the level at thesource.Parallel Mono OperationFollow these instructions for Parallel Mono Operation using a singleinput cable, and you will have the same monophonic signal on both thechannel A and the channel B outputs. Each channels output iscontrolled independently by that channels level control.1. With the power off, set the OPERATION MODE SWITCH (3) to thePARALLEL MONO position. When the power is on, the MONO LED(12) on the front panel will light. If the LED does not illuminate, youhave the switch in the wrong position. Correct before continuing.2. With the power off, connect your input cables to the channel A inputonly using the either the XLR INPUT JACK (5) or 1/4 INPUT JACK(4) of channel A. The other channel A input can be used to link to anadditional amplifier.3. Connect the loudspeakers to the channel A and channel B SPEAKEROUTPUTS (9, 11). THE TOTAL SPEAKER LOAD MUST BE AT LEAST2 OHMS PER CHANNEL. If you try to operate at a lower impedance,the amplifier will go into protection mode and stop operation until youcorrect the load conditions.4. With the LEVEL CONTROLS (17, 18) set to zero (fullycounterclockwise), switch the power on. Apply a signal to the input.The level of the input signal should be as high as you will ever needit to be. This way, it will be as high above the amplifiers noise flooras possible, ensuring an excellent performance and signal to noiseratio. Adjust the LEVEL CONTROLS for each channel to achieve thedesired maximum listening level. Note, when the clip LEDs light, thereis distortion present in the amplifiers output section. If a clip LEDremains on or flashes repeatedly, reduce the signal level by loweringthe input level control for the channel that is clipping or reduce thelevel at the source.Mono Bridge OperationFollow these instructions to bridge the units outputs. Bridging theamplifier converts the unit to a monophonic or single channel. Theamplifier can be used with 8 Ohm or higher loads only in Mono Bridgemode. This mode is used to provide a higher voltage with greaterheadroom to your speaker. Before setting your amplifier for Mono Bridgeoperation, make sure that your speaker can handle the high power levelprovided by the amplifier in Mono Bridge mode. CAUTION: VOLTAGEOVER 100 VOLTS MAY BE PRODUCED AT THE BRIDGE OUTPUTTERMINALS IN THIS MODE.1. With the power off, set the OPERATION MODE SWITCH (3) to theBRIDGE position. When the power is on, the BRIDGE LED (13) onthe front panel will light. If the LED does not illuminate, you have theswitch in the wrong position. Correct before continuing.2. With the power off, connect your input cables to channel A inputonly using the either the XLR INPUT JACK (5) or 1/4 INPUT JACK(4) of channel A. The other channel A input can be used to link to anadditional amplifier.3. Connect the loudspeaker to the BRIDGE SPEAKER OUTPUT (10)only. With a 230V unit, use the center speakon. With a 120V unit,use the two innermost red terminals. Be sure the polarity of yourconnections is correct. The total speaker load must be at least 4Ohms or above. If you try to operate at a lower impedance, theamplifier will go into protection mode and stop operation until youcorrect the load conditions.4. With the CHANNEL A LEVEL CONTROL (17) set to zero (fullycounterclockwise), switch the power on. Apply a signal to the input.The level of the input signal should be as high as you will ever needit to be. This way, it will be as high above the amplifiers noise flooras possible, ensuring an excellent performance and signal to noiseratio. Adjust the LEVEL CONTROL (17) for channel A to achieve thedesired maximum listening level. Note, when the clip LEDs light, thereis distortion present in the amplifiers output section. If a clip LEDremains on or flashes repeatedly, reduce the signal level by loweringthe input level control for channel A or reduce the level at thesource. During Mono Bridge operation, the channel B level isinactive, however, both channels LEDs will flash simultaneously andshow output conditions.Using the Signal Ground Lift SwitchDepending on your system configuration, sometimes applying theground will create a quieter signal path. Sometimes lifting the groundcan eliminate ground loops and hum to create a quieter signal path.1. With the power amp on, listen to the system in idle mode (no signalpresent) with the ground applied (the SIGNAL GROUND LIFTSWITCH (8) in the left position).2. Then turn the power off before moving the SIGNAL GROUNDLIFT SWITCH (8). Lift the ground by moving the SIGNAL GROUNDLIFT SWITCH to the right, turn the power back on and listen todetermine which position will provide a signal devoid of backgroundnoise and hum. Keep the SIGNAL GROUND LIFT SWITCH in theground position if the noise level remains the same in either position.CAUTION: DO NOT TERMINATE THE AC GROUND ON THE POWERAMPLIFIER IN ANY WAY. TERMINATION OF THE AC GROUND CAN BEHAZARDOUS.(6)UNIT DOES NOT PRODUCE SOUND. POWER LEDDOES NOT LIGHT. POWER SWITCH NOT IN ON POSITION. POWER CABLE NOT CONNECTED TO AMPLIFIEROR TO OUTLET. AC OUTLET NOT ACTIVE. MAIN AMPLIFIER FUSE DEFECTIVE. MOVE POWER SWITCH TO ON POSITION. CONNECT POWER CABLE TO AC SUPPLY. CHECK CONDITION OF OUTLET. REPLACE AMPLIFIER MAIN POWER FUSE ON REAR PANEL WITH CORRECTTYPE AND RATING.LOUD 50/60 HZ OR 100/120 HZ HUM IS HEARD ATALL TIMES THROUGH THE SPEAKER SYSTEMS. IMPROPER OR DEFECTIVE GROUNDCONNECTION AT INPUTS. IMPROPER ORDEFECTIVE GROUND AT INPUT SOURCE DEVICE(S). IMPROPER OR DEFECTIVE GROUNDCONNECTION ON AC OUTLET. GROUND LOOP THROUGH AC LINE CONNECTION/RACK MOUNTING. CHECK FOR PROPER AC LINE GROUND ON POWER AMP AND ALL INPUTDEVICES. CHECK INPUT CABLES FOR ALL SOURCE DEVICES AND SIGNALPROCESSING AS WELL AS INPUT CABLES TO POWER AMPLIFIER. CHECKPOSITION OF GROUND LIFT SWITCH AS PER INSTRUCTIONS FOR LIFTINGTHE GROUND. NEVER LIFT THE AC LINE GROUND ON THE POWER AMPLIFIER. IF YOUARE NOT TOTALLY FAMILIAR WITH GROUND LIFTING OR UNIFICATIONPROCEDURES, DO NOT ATTEMPT THEM WITHOUT FIRST CONSULTINGYOUR DEALER OR A QUALIFIED SOUND TECHNICIAN FOR MOREINFORMATION ON GROUNDING. IMPROPERLY DONE, SUCH PROCEDURESCAN POSE A SAFETY AND/OR FIRE HAZARD.SOUND IS DISTORTED. DISTORTION OCCURRING IN SOURCE DEVICE. INPUT LEVEL IS SET TOO HIGH. CHECK CLIP INDICATORS ON INPUT SOURCE DEVICES AND RESET LEVELSIF NECESSARY TO ELIMINATE DISTORTION. ADJUST LEVEL CONTROLS AS PER INSTRUCTIONS.PROTECT LED REMAINS LIT OR GOES ON ANDOFF INTERMITTENTLY AFTER USING AMPLIFIERFOR A SHORT TIME. UNIT IS OPERATING AT EXCESSIVELY HIGHTEMPERATURE. EXTREMELY LOW SPEAKER IMPEDANCE. SHORT IN SPEAKER CONNECTORS, SPEAKERCABLE OR SPEAKER SYSTEM. CHECK THAT AMPLIFIER IS ADEQUATELY VENTILATED ON THE FRONTAND REAR PANELS WHERE THE AIR VENTS AND FANS ARE LOCATED. IFOVERHEATED, LET THE AMPLIFIER COOL DOWN BEFORE APPLYING ANINPUT SIGNAL. CHECK THE POSITION OF OPERATION MODE SWITCH. BE SURE THAT THESPEAKER CONNECTIONS ARE MADE IN ACCORDANCE WITH THE SWITCHSETTING. VERIFY SPEAKER SYSTEM IMPEDANCES. BE SURE THE TOTAL SPEAKERSYSTEM IMPEDANCE IS AT LEAST 4 OHMS PER CHANNEL WHEN THEOPERATION MODE SWITCH IS IN THE STEREO POSITION OR PARALLELMONO POSITION. IF THE SWITCH IS IN THE BRIDGE MODE, THE IMPEDANCEMUST BE AT LEAST 8 OHMS. IF YOU ARE NOT SURE OF YOUR TOTALSPEAKER IMPEDANCE LOAD, CONTACT YOUR DEALER FOR MOREINF