Sphinx-PhonoEqualizer-riaa-sm 维修电路原理图.pdf

1. SERVICE MANUALPHONO EQUALISERRadioFans.CN 收音机爱 好者资料库SPHINX Phono equaliser Service Manual 2 1. UNPACKING.32. CONTACTING THE MANUFACTURER.33. THE PHONO EQUALISER AT A GLANCE.4Front panel.4Rear panel .54. INSTALLATION AND CONNECTIONS.6Installation.6Connecting the mains cable .6Audio connections .6Connecting the pre-amp .6Connecting the turntable.6Connecting the optical cables.65. CHANGING THE SETTINGS.7Removing the cover.7a. LED: Project or Myth Series standard.7b. Input sensitivity (Gain) .8c. Input capacity (MM).8d. Cartridge type / Input impedance.9e. RIAA or 78 rpm.9f. 78 rpm filter.9Replace the cover.96. OPERATION.10Switching on.10Standby.10Switching off.107. THE 78 RPM MODES .108. CARE AND MAINTENANCE.119. TECHNICAL SPECIFICATIONS.1110. PROBLEMS AND SOLUTIONS.1211. DIAGRAMS AND PARTS LIST.13Overview Components.14General Overview Phono Equaliser.15Amplifier.16Power Supply and Control .17Parts List.18RadioFans.CN 收音机爱 好者资料库SPHINX Phono equaliser Service Manual 3 The Sphinx Phono equaliser designThis service manual will help you to optimallyservice and repair the Sphinx Phono equaliser.The Phono equaliser active MM and MC phono pre-preamplifier is the first to obtain the extremely highaudio quality standards of the Sphinx product line.The design has therefor been only been finalisedafter numerous intensive comparative listeningsessions. It is based on a radically new amplifierdesign using special complementary FETs in asingle housing (the same that are used for theProject Eight preamplifier). This is guarantees ultra-low noise and an incomparable transient response.It offers numerous user adjustable settings for MMand MC (Gain, Impedance, etc.). This enables youto fine-tune the Phono equaliser to almost anycartridge on the market.It is however not confined to the regular MM andMC cartridges but in addition offers special settingsfor the use of 78-rpm records!One of which is a specially designed filter: thisensures the correct playback correction curve. Andthus prevents the usual annoying increased surfacenoise of the records when played via normalphono preamps. It restores the actual sound qualityof the records.To obtain the maximum quality from this Phonoequaliser it is necessary to use it with top qualityaudio components, preferably with other Sphinxcomponents. The Phono equaliser may be used withcomponents from the Sphinx Project Series, theMyth Series and even with non-Sphinx products.1. UNPACKINGBefore leaving the factory every Phono equaliser issubjected to stringent and extensive technical andexterior quality inspection.This ensures you will enjoy many years of highquality audio performance from a perfect-lookingproduct.After unpacking your Phono equaliser we thereforerecommend you carefully check it for any transportdamage.In case of damage: please contact your Sphinxdealer immediately and retain all packing materialsfor possible proof of damage and possible claims.Even if the component is in perfect condition youshould still keep the packing materials. If you needto transport your Phono equaliser at a later time itwill be best protected by the original packingmaterials.2. 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.SPHINX Phono equaliser Service Manual 4 3. THE PHONO EQUALISER AT A GLANCEFront panel1. LED:ingreen(for Myth Series: not illuminated)StandbyredSPHINX Phono equaliser Service Manual 5 Rear panel2. R IN: Connect to this input the right (red) outputcable from the turntable.3. L IN: Connect to this input the left (white orblack) output cable from the turntable.4. R OUT: Connect this output to the right input ofthe (pre-) amplifier5. L OUT: Connect this output to the left input ofthe (pre-) amplifier.6. GND: Connect here the separate ground wirefrom the turntable.Also connect here the ground wire from the(pre) amplifier (if applicable).7. Control IN: Connect here the optical cable fromanother Sphinx components Control Out(usually the preamplifier).8. Control OUT: Connect here the optical cablethat goes to another Sphinx componentsControl In.9. AC IN: Connect the mains cable to a mainspower outlet (100 - 240 VAC).10. Manufacturers label: (at housing underside)This shows important data for the component,such as serial number and mains powervoltage.SPHINX Phono equaliser Service Manual 6 4. INSTALLATION AND CONNECTIONSInstallationThe Phono equaliser will not become very hot, soplacement is not critical, although you should notplace it on top of or near other heat-radiatingequipment (such as power amps) or in directsunlight.If you use it in a closed cabinet or on a bookshelf,please ensure unrestricted ventilation around thecomponent.To prevent any possible interference keep powersupply cables away from all audio cables.Note: The mains power transformer of the Phonoequaliser is mounted at the front side.Position the Phono equaliser as close to theturntable as possible while keeping the cables asshort as possible.Always connect the separate ground wire from theturntable to the GND terminal (6).If all these conditions are met, the Phono equaliserwill perform to the extremely high standards it isdesigned for.Connecting the mains cableBefore you connect the cable please checkwhether the mains voltage indicated on themanufacturers label on the rear panel is thesame as your local mains voltage.If not: please contact your dealer and do not connectthe component to the mains.The Phono equaliser does not have a dedicatedon/off switch. After you have connected it to themains power it will always be active while the defaultsetting is ON.This way the electronic circuits will be kept atoptimum working temperature so you can enjoymaximum audio quality immediately after switchingon. Additionally it significantly increases the life spanof the component.Via the Control IN input (7) however it may beremotely switched to Standby by another Sphinxcomponent.Connect the mains cable after you have connectedall other components in the system, have double-checked all connections and after the Phonoequaliser has been matched to the cartridge in use(see Chapter 5).Audio connectionsBefore you start connecting equipment it is alwayswise to check whether all the mains power cables ofall components are disconnected from the mainsoutlets! This will prevent any damage to theloudspeakers and amplifiers caused by incorrectwiring or settings.Make sure you connect L and R properly. Most cinchcables use Red for the Right channel and White orBlack for Left.The cinch connectors on the rear panel of the Phonoequaliser have a red centre for the right channel anda white one for the left channel.When making the connections please refer to thedescriptions for parts 2. to 10. on page 5.Connecting the pre-ampConnect the R OUT (4) and L OUT (5) to the LINE-or AUX inputs of the pre-amp, using normal cinchcable (but of top quality!).Connect the separate ground wire (if supplied) fromthe pre-amp to the GND terminal (6).Connecting the turntableConnect the (in most cases fixed) audio cable fromthe turntable to the R IN (2) and L IN (3).Connect the separate ground wire from the turntableto the GND terminal.Connecting the optical cablesConnect the CONTROL OUT of a Sphinx pre-amp tothe CONTROL IN (7) of the Phono equaliser. It willthen switch to Standby mode as soon as the pre-amp is set to Standby.Connect the Phono equalisers CONTROL OUT (8)to the CONTROL IN of another Sphinx component. Itwill then automatically switch to Standby as soon asthe Phono equaliser is selected to Standby.Ensure proper connection of the optical cables,otherwise the Standby LED on the front panel mayremain off, even though the Standby mode isactivated.If the CONTROL IN is not used and the Phonoequaliser is placed in strong direct sunlight, theStandby mode may self-activate.In that case you should place the supplied dummyconnector in the CONTROL IN jack.SPHINX Phono equaliser Service Manual 7 5. CHANGING THE SETTINGSThe Phono equaliser may be used with a widerange of cartridges, including the 78 rpm types.Before you can use the Phono equaliser it shouldtherefore be matched to your specific cartridge andapplication.In addition there are two special filters that may beselected.Note: The rumble filter (12 dB/octave10 Hz) cannot be deselected.And you can even select the working mode of theLED on the front panel: Project Series or MythSeries!In order to select the correct settings youll need thefollowing data:a. The type of audio system:Sphinx Project or Myth SeriesRe. the cartridge:b. The output sensitivityc. The output capacitanced. The type: MM or MC andthe output impedanceAnd finally:e. The type of records: normal or 78 rpm.These data you may find in the manuals and/ortechnical specifications of the equipment.Write these (preferably with a pencil) into the lastcolumn of the following table.The Phono equalisers default values are marked inthe first column:SettingDefaultYour dataa.LED:Project Seriesb.High Gain(250-750 V)c.47 pFd.MC cartridge200 ohme.RIAAf.78 rpm filter OFFThis simplifies the procedure while showing exactlythe default value(s) differing from your data andthus which setting(s) need to be changed!A. Default values match your data and systemYou do not have to change anything, may skip thischapter, go straight to Chapter 6 and start using thePhono equaliser.B. Some values are differentIn that case you may have to change one or moresettings. You should use the following proceduresto ensure correct results.You may refer to the sticker inside the covershowing the settings for each DIP-switch.Which setting should be changed is whollydependent on the default values that differ fromyour data.Note: If you have to change more values, the orderin which you adjust settings a f is not important.ATTENTION: Before starting the proceduresalways first disconnect the mains cable fromthe power outlet!Removing the coverCarefully (to prevent any scratching of the surface)remove the small Phillips screws on the left-handside and on the right-hand side.Remove the cover and store it in a safe place.However, make sure that you are able to read thesticker on the inside when necessary.Youll see the mains transformer and the circuitboard with the components and switches.The Phono settings are changed by means of thesmall switches in the four red switch blocks(showing the text ON).The LED setting is changed with the small shortingplug (positioned closest to the 8-pin power supplyconnector at the front of the housing).a. LED: Project or Myth Series standardWhen using the Phono equaliser with the SphinxMyth Series you are able to give the LED (1.) thesame functionality as that on the Myth Series (whenthe equipment is on the LED is off).- Remove the red shorting plug.- You will see two free pins.- Replace the plug so it covers both pins.- Ready!If there are no other settings to be changed youmay continue with “Replace the cover”. Otherwiseselect one of the following settings.SPHINX Phono Equaliser Service Manual 8 b. Input sensitivity (Gain)It is important to match the input sensitivity of thePhono equaliser to the output value of the cartridgein use. Only this will ensure the maximum S/N ratioand will prevent distortion.The Gain has three settings:- High: for cartridges with an output signalbetween 250 V and 750 V.- Mid: for cartridges with an output signalbetween 750 V and 1,5 mV.- Low: for cartridges with an output signalbetween 1,5 mV and 15 mV.The Gain is set with switches 1 and 2 of the largered switch blocks (one for each channel).Using the value of your cartridge (as marked in thetable), move the switches to the correct valueaccording to one of the following pictures.c. Input capacity (MM)This setting is specifically for MM cartridges. Thestandard value is 47-pF, but some cartridges needa value of 147-pF for optimum results.Note: This setting has no influence on the MCsettings.The standard value is LOW (47-pF).You select the HIGH value by moving switch 3 tothe upper (ON) position.SPHINX Phono Equaliser Service Manual 9 d. Cartridge type / Input impedanceFor each cartridge type you need to set the correctinput impedance.You may find the value for your cartridge in itsmanual under the technical specifications.The impedance is set with switches 4, 5 and 6.If your MC cartridge needs an impedance otherthen 200 ohm you may select:- 100 ohm or- 50 ohm.For a MM cartridge however you can only select:- 51 kohm.e. RIAA or 78 rpmThe standard replay correction is RIAA, this is alsosuitable for many 78 rpm records. The Phonoequaliser can be switched to a special 78 rpmcurve needed by certain records (see alsoChapter-7. “The 78 rpm modes”).This is set with switches 1 and 2 on the small redblocks.f. 78 rpm filterTo ensure proper 78 rpm replay quality with modernaudio systems, it is necessary to use a special low-pass filter. Otherwise the frequencies above 4 kHzwill become too emphasised. After selecting thisfilter the replay quality will be more according to theold standards.Replace the coverAfter you have changed the settings we advice youto recheck whether each setting is correctly done. Itis also very useful to make a note of all thechanges you have made for future reference.Then replace the cover and tighten the screws.The Phono equaliser is now ready for use with youraudio system.SPHINX Phono Equaliser Service Manual 10 6. OPERATIONAfter you have properly adjusted all settings youmay start using the Phono equaliser.Connect the mains cable to a mains outletThe LED (1) will blink red for some time after whichit changes to green (when the Myth setting isselected it will go off).Switching onThe Phono equaliser per default is always switchedon and can not be switched off.This way the electronic circuits will be kept atoptimum working temperature so you can enjoymaximum audio quality immediately after switchingon. Additionally it significantly increases the lifespan of the component.StandbyThe Phono equaliser may be remotely switched toStandby by another Sphinx component if it isconnected to the CONTROL IN (7) optical input.The LED will switch to red.Switching offThe only way to switch the Phono equaliser offcompletely is to unplug the mains cable.7. THE 78 RPM MODESWhen cutting a record master for vinyl records theaudio signal is sent (for technical reasons) througha special correction equaliser: this increases thehighs and decreases the lows. During replay of therecord this correction curve is reversed by thereplay filter in a phono pre-amp.The RIAA curve is an international standard curvefor 33 and 45 rpm records. This attenuates thefrequencies above 2120 Hz and amplifies thosebelow 500 Hz (these points are also