Sphinx-Project12-pwr-sm 维修电路原理图.pdf

1. SERVICE MANUALPROJECT TWELVEMONOPOWER AMPLIFIERRadioFans.CN 收音机爱 好者资料库SPHINX Project Twelve Service Manual 2 Contents1. UNPACKING.32. SPHINX WARRANTY CARD .33. CONTACTING THE MANUFACTURER.34. THE POWER AMP AT A GLANCE.4Front panel.4Rear panel .55. TECHNICAL SPECIFICATIONS.66. GENERAL CHECKLIST.7Optical connections .7Switching the amp on.7Protection mode.7Cables.77. USING THE AMP WITHOUT PROTECTION CIRCUIT.8Removing the protection circuit board .8Repositioning the protection circuit board.88. ADJUSTMENT PROCEDURES.9Bias.9Offset .10Common mode .109. PROBLEMS AND SOLUTIONS.1110. DIAGRAMS AND PARTS LISTS .12Connection diagram for testing the project 12.13Schematic layout of project 12 with securityprint.14Schematic layout of all relevant parts.15Project 12 amplifier diagram.16Project 12 protection diagram.17PCB drawings of Project 12.18Partlist amplifier .19Partlist protection.22RadioFans.CN 收音机爱 好者资料库SPHINX Project Twelve Service Manual 3 The Sphinx Project Twelve designThe Sphinx Project Twelve was designed for theever-increasing group of quality-consciousaudiophiles.We are very proud of the tradition connected withthe SPHINX name, especially concerning audioquality perfection.This service manual will help you to optimallyservice and repair the Sphinx Project Twelve MonoPower Amplifier.The design is based on the long experience of theSphinx design team with ultra-wide bandwidthpower FETs.These have an unique and extremely wide powerbandwidth exceeding 1.5 MHz, a very high slewrate of over 100 V/s and an unequalled perfectphase linearity over the complete frequencybandwidth.Six of these 100 W FETs are used to obtainmaximum reliability.The extremely low output impedance results in adamping factor of over 600!Together with the very heavy power supply and itslarge energy buffer of 26,920 F, this results in aneffortless sound with a very large dynamic rangeand an unsurpassed transient response.Much attention has also been paid to the physicallayout, the positioning of components and theinternal grounding. This results in an equivalentinput noise value of 1 V (-120 dBV): remarkablefor a pre-amp, but really astounding for a big poweramp with two transformers.All of this means that the Project Twelve can workwith all kind of loads from every loudspeaker: eventhe most difficult ones like electrostatic andmagnetostatic.To obtain the maximum quality from this power ampit is necessary to use it with top quality audiocomponents preferably with other Sphinxcomponents.1. UNPACKINGBefore leaving the factory every Project Twelve issubjected to stringent and extensive technical andexterior quality inspections. This ensures the usermany years of high quality audio from a perfect-looking product.We recommend owners to ship the Project Twelvein its original carton.After unpacking the Project Twelve we thereforerecommend you carefully check it for any transportdamage.If you find any damage and the product has notbeen shipped in the original carton the ensuingrepair costs will not be covered by the warranty.2. SPHINX WARRANTY CARDTo be entitled to any warranty repairs the ownermust have send the filled out warranty card toSphinx or a distributor where it has been registered.Other regulations may apply in your specificcountry: when in doubt, please consult the properauthorities.3. CONTACTING THE MANUFACTURERIn case of any problem not covered in this manualor if you have other questions you may contact theSphinx International Service Department in TheNetherlands (local time: GMT +1h) during officehours at the following numbers:Telephone(+31) 35 602 0302Fax(+31) 35 602 2806E-mailaudionleuronet.nlIt is always very helpful and efficient if you have allrelevant information about the specific product andthe problem ready.Please also refer to the User Manual of theProject Twelve for information aboutfunctions not described in this manual.It is important to familiarise yourself with thespecial functions, operation and possibilitiesof the Sphinx Project Twelve.SPHINX Project Twelve Service Manual 4 4. THE POWER AMP AT A GLANCEFront panel1. LED: Indicates the selected function:stand-byredongreenprotectionblinking red.2. STANDBY: To switch the component on and off.SPHINX Project Twelve Service Manual 5 Rear panel3. BALANCED/UNBALANCED: With this switchyou may select the balanced input (5.) or theunbalanced input (8).4. CONTROL IN: To connect the optical cablefrom another Sphinx component like a pre-amp.CONTROL OUT: To connect the optical cablethat goes to another Sphinx component.5. BALANCED INPUT: To connect the balancedXLR cable from the pre-amp output.6. MAINS: This is the combined mains masterswitch (0/1) and input.MAINS: To connect the power amp to a mainsoutlet (230 - 240 VAC).7. OUTPUT: To connect the cable from theloudspeaker:red+white-8. UNBALANCED INPUT: To connect theunbalanced cinch cable from the pre-ampoutput.Manufacturers label: Here youll findimportant data on this component, such asserial number and mains voltage to be used.SPHINX Project Twelve Service Manual 6 5. TECHNICAL SPECIFICATIONSBandwidth0 - 1.5 MHz (+0/-3 dB)0 - 203,000 Hz after RF input filterPhase response error151 W into 8 ohm (21.8 dBW), THD 246 W into 4 ohm (23.9 dBW), THD 340 W into 2 ohm (25.3 dBW), THD 0.01%Output voltage / current, max.36 V / 16 ATHD+N (IHF-A)0.006% (100 W into 8 ohm, 1 - 20,000 Hz)IMD120 dBSlew rate20 V/sCommon Mode Rejection Ratio30dB 100 HzDamping factor645 10 Hz629 100 Hz595 1 kHz155 10 kHzInputXLR balanced / cinch WBT unbalanced level, nominal1.25 V (1.9 dBV) / 1.25 V (1.9 dBV) impedance600 ohm / 20 kohmSupply capacitance26,920 F totalPower consumption600 W max. (5 W standby)Power transformer, primary230 VAC / 115 VAC secondary45 VAC / 3,33 A (2x)Temperature protection70 C / 158 FMaximum DC-offset+350 mV and 350 mVShort circuit protectionMeasured at source resistor R31Dimensions (h x w x d)68 x 250 x 340 mmWeight6,5 kgThis unit conforms to the EMC interference regulations issued by the EU and to the CE standards.This unit complies with safety regulation VDE 0860 and therefore with international safety regulation IEC 65.Technical specifications may be changed by SPHINX without prior notice if technical developments make thisnecessary.SPHINX Project Twelve Service Manual 7 6. GENERAL CHECKLISTBefore you test or service the Project Twelveplease check the following items. They will giveinformation about the current status of the amplifier.Note: The Project Twelve will become warm, socorrect placement is critical. Do not position it ontop of or close to other heat-radiating equipment(such as other power amps) or in direct sunlight.Please ensure unrestricted ventilation aroundthe component.Optical connectionsThe optical CONTROL IN (4.) is light-sensitive. Astrong light source might therefore activate theCONTROL function and switch the Project Twelveto Standby.While this mode has priority the amplifier can notbe activated with the Standby switch at the frontpanel.Before you start connecting equipment it is alwayswise to check whether all the mains cables of allcomponents are disconnected from the mainsoutlets!This will prevent any damage to the loudspeakersand amplifiers caused by incorrect wiring orsettings.Connect the mains cable after you have connectedall other components in the system and havedouble-checked all connections.If you use more than one Project Twelve connecthem all to the same mains outlet and phase.Switching the amp onBefore you switch the power amp on you shouldalways first: connect a pre-amp connect the pre-amps Control Out to the poweramps Control In or place the dummy plug in the Control INconnector of the power amp.After switching the amplifier ON the red LED (1.)will first blink slowly (1x per second) and then willlight continuously.The amp is now in Standby mode.Pressing the Standby-button (2.) will activate theamplifier and the LED turns to green.Protection modeIf - after switching on - the red LED (1.) blinksrapidly (2x per second) this indicates that theprotection mode is active.This may be caused by one of the followingproblems:1. The operational temperature exceeds 70 C.2. The output DC-offset exceeds +/- 350 mV.3. The output is shorted (current-limiter active)4. Power supply voltage is wrongly connected orlow (for correct voltage see underside of PJ 12)The protection mode will do the following things:1. Disconnect the amplifier output.2. Disconnect the amplifier input.3. Reset the bias current to 0 mA.The protection mode can only be deactivated byswitching the amplifier off with the Mains Switch (6.)and leave it off for at least 30 seconds.If the amplifier is switched on again within those 30seconds the protection mode will automatically beactivated.Note: This also happens if the amplifier workedproperly before switching it off!CablesAlways use loudspeaker and audio cables andconnectors of the highest quality.Siltech cable is used throughout internally and werecommend using this same cable for all externalconnections.If you have the choice between longer loudspeakercables or longer audio cables, choose the latter(cables between pre-amp and power amp willcause the least signal quality loss).Warning!The output Short-circuit protection will beactivated at output currents of over 27A. Atlower output currents (AC or DC) the amplifierhas no direct protection. At continuous largecurrents, the temperature protection will takeover.SPHINX Project Twelve Service Manual8 7. USING THE AMP WITHOUTPROTECTION CIRCUITTo adjust the internal controls of the Project Twelvethe protection circuit board may be removed.This ensures that all adjustment points on the mainboard are freely visible and accessible (instead ofthrough small openings in the protection circuitboard).Removing the protection circuit boardThe protection circuit board is mounted on top ofthe upper main printed circuit board of the amplifier.The drawing “Schematic layout of project 12 withsecurityprint” (page 14) shows the main board ofthe Project Twelve with the protection circuitincluding all the parts mentioned below. Use thefollowing steps:1. Remove the top cover plate of the amp. It isfixed with one hex screw (M4x12) at the rearpanel2. Remove the two small screws (M3x6) of theprotection circuit board.3. Unsolder the five wires at the top-left corner(Audio-IN).4. Unsolder the two PTC-resistors (for the over-temperature protection at 70 C).5. Carefully remove the circuit board (there is onlyone way of doing this due to the mountedBalanced/Unbalanced switch):a) Lift up the front side of the board so the largeconnector is disconnected from the main circuitboard.b) Lift the rear side of the board to disconnectthe other connector.Now you may remove the board.6. Connect the input signal to the main circuitboard with the special Servicing Cable (*).7. Reposition the jumper from JP2 & JP3 to JP1 &JP2.The output relay now works without controlsignal from the protection circuit.Repositioning the protection circuit boardTo reposition the protection circuit board you usethe steps from the previous “Removing the”-procedure but in reverse order.1. Reposition the jumper from JP1 & JP2 to JP2 &JP3.If not, the protection circuit will not be able todisconnect the amplifiers output.2. Position the board over the mounting positionsand stick the Balanced/Unbalanced buttonthrough the appropriate opening in the rearpanel of the housing.3. Carefully insert the rear connector into thecorresponding main circuit board socket andthen the front connector in its socket.4. Fix the protection circuit board position with thetwo small screws.5. Solder the five wires to their correct positions(position #1 is the one at the rear, see also thedrawing):1) Red (+) wire from BALANCED IN2) Red (+) wire from UNBALANCED IN3) Black wire (ground) from BALANCED IN4) Black wire (ground) from UNBALANCED IN5) Blue (-) wire from BALANCED IN.6. Solder the two PTC-resistors to the circuitboard.7. Replace the top cover plate of the housing andfix it with the hex screw.(*) If there is no Servicing Cable available you maymake one yourself using a suitable connector.Connect the wires as follows: Pin 1 (and 2) = negative signal: connect to bluewire from Balanced In Pin 3 (and 4) = ground: connect to black wire ofboth inputs Pin 5 (and 6) = positive signal: connect to redwire of both inputsThe 6 pin connector at the main board then can beused as the signal input.WARNING!The amplifier may be used without the protectioncircuit.We do not recommend this however while thisprevents the output from being disconnected incase of any malfunction.SPHINX is not responsible for any damagecaused by the removal of the protectioncircuit or the use of the amp without theprotection circuit!Attention:Incorrectly positioned connectors may causedamage to the Project Twelve and the pre-amp.SPHINX Project Twelve Service Manual9 8. ADJUSTMENT PROCEDURESThe Project Twelve has three adjustable settings:1. Bias: to set the bias current of the power-FETs2. Offset: to set the minimal DC voltage for theoutput3. Common Mode: to maximise the commonmode rejection of the balanced inputRe-adjustment of one or more might be necessarydue to ageing or when parts have been replaced orrepaired.After removing the top cover plate you will see thethree main sections of the amplifier:1. The power transformer2. The main printed circuit board holding theactual audio amplifier3. The protection circuit board responsible forswitching the Project Twelve on and off.BiasWith this procedure you set the proper bias level forthe power FETs. This ensures their Class Aoperation at low power levels.Connect the amplifier according to the drawing“conection diagram for testing the project 12” (page13).The input of the amplifier must be shorted (by wayof the MUTE function of the oscillator). Switch the amplifier ON and wait until it hasreached the proper working temperature (thistakes an hour). Set the millivolt-meter to the DC-range. Place the two measuring clips of the meteracross one of the source resistors (R30, R31,R39, R40, R43 or R45: see schematic at page15). The level should be 10 mV DC (2 mV).If not: adjust potmeter P2 until the level is10 mV (P2 can be reached via the biasadjustment hole in the protection circuit board). Switch the oscillator on and set it to 1 kHz and alevel of 0 dBu. Check the distortion with a THD analyser: itshould be conform the specified values (0.006%IHF-A 1 kHz). If this is correct the procedure is finished. You may now switch off the amplifier orcontinue with another adjustment procedure.Attention:When re-adjusting any setting please ensure thatthere is no loudspeaker connected to the output!Otherwise the loudspeaker may be seriouslydamaged.Attention:The amplifier is able to generate high outputvoltages of over + or -60 V.Please be very careful during the adjustments!Attention:All source resistors must show the same 10 mVvalue. If not this indicates that the FETs are notaccurately matched and their variance is too high.This will cause offset- an