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1、1. SERVICE MANUAL PROJECT TWELVE MONO POWER AMPLIFIER RadioFans.CN 收音机爱 好者资料库 SPHINX Project Twelve Service Manual 2 Contents 1. UNPACKING.3 2. SPHINX WARRANTY CARD .3 3. CONTACTING THE MANUFACTURER.3 4. THE POWER AMP AT A GLANCE.4 Front panel.4 Rear panel .5 5. TECHNICAL SPECIFICATIONS.6 6. GENERAL
2、 CHECKLIST.7 Optical connections .7 Switching the amp on.7 Protection mode.7 Cables.7 7. USING THE AMP WITHOUT PROTECTION CIRCUIT.8 Removing the protection circuit board .8 Repositioning the protection circuit board.8 8. ADJUSTMENT PROCEDURES.9 Bias.9 Offset .10 Common mode .10 9. PROBLEMS AND SOLUT
3、IONS.11 10. DIAGRAMS AND PARTS LISTS .12 Connection diagram for testing the project 12.13 Schematic layout of project 12 with securityprint.14 Schematic layout of all relevant parts.15 Project 12 amplifier diagram.16 Project 12 protection diagram.17 PCB drawings of Project 12.18 Partlist amplifier .
4、19 Partlist protection.22 RadioFans.CN 收音机爱 好者资料库 SPHINX Project Twelve Service Manual 3 The Sphinx Project Twelve design The Sphinx Project Twelve was designed for the ever-increasing group of quality-conscious audiophiles. We are very proud of the tradition connected with the SPHINX name, especial
5、ly concerning audio quality perfection. This service manual will help you to optimally service and repair the Sphinx Project Twelve Mono Power Amplifier. The design is based on the long experience of the Sphinx design team with ultra-wide bandwidth power FETs. These have an unique and extremely wide
6、 power bandwidth exceeding 1.5 MHz, a very high slew rate of over 100 V/s and an unequalled perfect phase linearity over the complete frequency bandwidth. Six of these 100 W FETs are used to obtain maximum reliability. The extremely low output impedance results in a damping factor of over 600! Toget
7、her with the very heavy power supply and its large energy buffer of 26,920 F, this results in an effortless sound with a very large dynamic range and an unsurpassed transient response. Much attention has also been paid to the physical layout, the positioning of components and the internal grounding.
8、 This results in an equivalent input noise value of 1 V (-120 dBV): remarkable for a pre-amp, but really astounding for a big power amp with two transformers. All of this means that the Project Twelve can work with all kind of loads from every loudspeaker: even the most difficult ones like electrost
9、atic and magnetostatic. To obtain the maximum quality from this power amp it is necessary to use it with top quality audio components preferably with other Sphinx components. 1. UNPACKING Before leaving the factory every Project Twelve is subjected to stringent and extensive technical and exterior q
10、uality inspections. This ensures the user many years of high quality audio from a perfect- looking product. We recommend owners to ship the Project Twelve in its original carton. After unpacking the Project Twelve we therefore recommend you carefully check it for any transport damage. If you find an
11、y damage and the product has not been shipped in the original carton the ensuing repair costs will not be covered by the warranty. 2. SPHINX WARRANTY CARD To be entitled to any warranty repairs the owner must have send the filled out warranty card to Sphinx or a distributor where it has been registe
12、red. Other regulations may apply in your specific country: when in doubt, please consult the proper authorities. 3. CONTACTING THE MANUFACTURER In case of any problem not covered in this manual or if you have other questions you may contact the Sphinx International Service Department in The Netherla
13、nds (local time: GMT +1h) during office hours at the following numbers: Telephone(+31) 35 602 0302 Fax(+31) 35 602 2806 E-mailaudionleuronet.nl It is always very helpful and efficient if you have all relevant information about the specific product and the problem ready. Please also refer to the User
14、 Manual of the Project Twelve for information about functions not described in this manual. It is important to familiarise yourself with the special functions, operation and possibilities of the Sphinx Project Twelve. SPHINX Project Twelve Service Manual 4 4. THE POWER AMP AT A GLANCE Front panel 1.
15、 LED: Indicates the selected function: stand-byred ongreen protectionblinking red. 2. STANDBY: To switch the component on and off. SPHINX Project Twelve Service Manual 5 Rear panel 3. BALANCED/UNBALANCED: With this switch you may select the balanced input (5.) or the unbalanced input (8). 4. CONTROL
16、 IN: To connect the optical cable from another Sphinx component like a pre-amp. CONTROL OUT: To connect the optical cable that goes to another Sphinx component. 5. BALANCED INPUT: To connect the balanced XLR cable from the pre-amp output. 6. MAINS: This is the combined mains master switch (0/1) and
17、input. MAINS: To connect the power amp to a mains outlet (230 - 240 VAC). 7. OUTPUT: To connect the cable from the loudspeaker: red+ white- 8. UNBALANCED INPUT: To connect the unbalanced cinch cable from the pre-amp output. Manufacturers label: Here youll find important data on this component, such
18、as serial number and mains voltage to be used. SPHINX Project Twelve Service Manual 6 5. TECHNICAL SPECIFICATIONS Bandwidth0 - 1.5 MHz (+0/-3 dB) 0 - 203,000 Hz after RF input filter Phase 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), TH
19、D 0.01% Output voltage / current, max.36 V / 16 A THD+N (IHF-A)0.006% (100 W into 8 ohm, 1 - 20,000 Hz) IMD120 dB Slew rate20 V/s Common Mode Rejection Ratio30dB 100 Hz Damping factor645 10 Hz 629 100 Hz 595 1 kHz 155 10 kHz InputXLR balanced / cinch WBT unbalanced level, nominal1.25 V (1.9 dBV) / 1
20、.25 V (1.9 dBV) impedance600 ohm / 20 kohm Supply capacitance26,920 F total Power consumption600 W max. (5 W standby) Power transformer, primary230 VAC / 115 VAC secondary45 VAC / 3,33 A (2x) Temperature protection70 C / 158 F Maximum DC-offset+350 mV and 350 mV Short circuit protectionMeasured at s
21、ource resistor R31 Dimensions (h x w x d)68 x 250 x 340 mm Weight6,5 kg This 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 specificati
22、ons may be changed by SPHINX without prior notice if technical developments make this necessary. SPHINX Project Twelve Service Manual 7 6. GENERAL CHECKLIST Before you test or service the Project Twelve please check the following items. They will give information about the current status of the ampl
23、ifier. Note: The Project Twelve will become warm, so correct placement is critical. Do not position it on top of or close to other heat-radiating equipment (such as other power amps) or in direct sunlight. Please ensure unrestricted ventilation around the component. Optical connections The optical C
24、ONTROL IN (4.) is light-sensitive. A strong light source might therefore activate the CONTROL function and switch the Project Twelve to Standby. While this mode has priority the amplifier can not be activated with the Standby switch at the front panel. Before you start connecting equipment it is alw
25、ays wise to check whether all the mains cables of all components are disconnected from the mains outlets! This will prevent any damage to the loudspeakers and amplifiers caused by incorrect wiring or settings. Connect the mains cable after you have connected all other components in the system and ha
26、ve double-checked all connections. If you use more than one Project Twelve connect hem all to the same mains outlet and phase. Switching the amp on Before you switch the power amp on you should always first: connect a pre-amp connect the pre-amps Control Out to the power amps Control In or place the
27、 dummy plug in the Control IN connector of the power amp. After switching the amplifier ON the red LED (1.) will first blink slowly (1x per second) and then will light continuously. The amp is now in Standby mode. Pressing the Standby-button (2.) will activate the amplifier and the LED turns to gree
28、n. Protection mode If - after switching on - the red LED (1.) blinks rapidly (2x per second) this indicates that the protection mode is active. This may be caused by one of the following problems: 1. The operational temperature exceeds 70 C. 2. The output DC-offset exceeds +/- 350 mV. 3. The output
29、is shorted (current-limiter active) 4. Power supply voltage is wrongly connected or low (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 protect
30、ion mode can only be deactivated by switching 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 30 seconds the protection mode will automatically be activated. Note: This also happens if the amplifier worked prop
31、erly before switching it off! Cables Always use loudspeaker and audio cables and connectors of the highest quality. Siltech cable is used throughout internally and we recommend using this same cable for all external connections. If you have the choice between longer loudspeaker cables or longer audi
32、o cables, choose the latter (cables between pre-amp and power amp will cause the least signal quality loss). Warning! The output Short-circuit protection will be activated at output currents of over 27A. At lower output currents (AC or DC) the amplifier has no direct protection. At continuous large
33、currents, the temperature protection will take over. SPHINX Project Twelve Service Manual 8 7. USING THE AMP WITHOUT PROTECTION CIRCUIT To adjust the internal controls of the Project Twelve the protection circuit board may be removed. This ensures that all adjustment points on the main board are fre
34、ely visible and accessible (instead of through small openings in the protection circuit board). Removing the protection circuit board The protection circuit board is mounted on top of the upper main printed circuit board of the amplifier. The drawing “Schematic layout of project 12 with securityprin
35、t” (page 14) shows the main board of the Project Twelve with the protection circuit including all the parts mentioned below. Use the following steps: 1. Remove the top cover plate of the amp. It is fixed with one hex screw (M4x12) at the rear panel 2. Remove the two small screws (M3x6) of the protec
36、tion 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 only one way of doing this due to the mounted Balanced/Unbalanced switch): a) Lift up th
37、e front side of the board so the large connector is disconnected from the main circuit board. b) Lift the rear side of the board to disconnect the other connector. Now you may remove the board. 6. Connect the input signal to the main circuit board with the special Servicing Cable (*). 7. Reposition
38、the jumper from JP2 & JP3 to JP1 & JP2. The output relay now works without control signal from the protection circuit. Repositioning the protection circuit board To reposition the protection circuit board you use the 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 to disconnec
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