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Dolby Laboratories CP65 manual A-ChainAlignment Procedures, c. Magnetic Preamplifier Adjustments

Models: CP65

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A-Chain Alignment Procedures

c. Magnetic Preamplifier Adjustments

Magnetic Alignment

7.Remove the Cat. No. 242 card and locate the reversible plug-in Magnetic Input Sensitivity header.

100mV

in

in 1V

The CP65 accepts a nominal operating input level of either 100 mV or 1V — chosen by the position of the reversible plug-in header. The input impedance of the CP65 is 100K at both input levels. In addition, some preamplifiers may require a termination resistor (usually 600 ohms). You can connect the termination resistors at the input barrier strip TB3 and TB4 "from mpu–no nr" terminals on the backplane. Note that changeover between projector 1 and projector 2 must be accomplished in the magnetic preamplifier.

If noise reduction is to be used for decoding 70 mm Dolby Stereo soundtracks, the header on the Cat. No. 242 B-chain card must be set to the 100 mV position.

If the existing non-Dolby magnetic preamplifiers are used, their compatibility with the CP65 must be ensured.

8. Re-install the Cat. No. 242 card and restore the NORMAL/BYPASS switch to the NORMAL position.

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Dolby Laboratories CP65 manual A-ChainAlignment Procedures, c. Magnetic Preamplifier Adjustments, Magnetic Alignment

Contents

Installation and Alignment Instructions Model CP65 Cinema ProcessorDolby Laboratories Inc Dolby Laboratories Inc U.S. HeadquartersU.K. European Office 100 Potrero Avenue San Francisco, CA TelephoneINTRODUCTION Table of ContentsINITIAL SET-UPAND INSTALLATION EQUIPMENT REQUIREDAPPENDIX C APPENDIX AAPPENDIX B APPENDIX D04 Dolby Stereo A-type 05 Dolby Stereo SR INTRODUCTIONCP65 60 Non-syncPage 2 1kHz, 100% Modulation, Left/Right - Cat. No SECTION EQUIPMENT REQUIRED1 Dolby Tone and Pink Noise - Cat. No 4Stereo Optical Surround Level - Cat. No TEST FILM3SMPTE Buzz Track JIFFYSECTION INITIAL SET-UPAND INSTALLATION Acceptable SettingVoltage Voltage RangeCat. No J5 J6 J7 J8 Cat. No. 249, Power Supply ModuleCat. No. 242, B-ChainCard Cat. No. 443, Control Logic Card J3 INCP65 Backplane Standard CP65 or CP65AIn a CP65-300when Cat. No. 300 modules are fitted in place of the normal Cat. No. 350 modules J16 and J18 should be rotated so that the words “Format 42” appears the right way up. With J24 in the “NR” position input signals will be A-typedecoded when the Mag/Aux format is selected. With J24 in the “NO NR” position signals pass through the noise reduction modules but the processing will be turned off. If both of these processing options are required frequently an external switch may be connected to J24 CP65-300J1 Optical Bass Extension output level sets the output level range for the subwoofer channel. In the HIGH position J1 is set at the factory for a power amplifier input sensitivity of between 90 mV and 1.23 V. If the power amplifiers used in the installation are very sensitive 10 mV to 100 mV input sensitivity, it may be necessary to set J1 to the LOW position. If you are unsure of the sensitivity of your power amplifiers set J1 to the LOW position initially. If the high output position is required this will be determined during OBE alignment Slot selected projector. Electronic switches selectCard Descriptions Card2 4 Channel Decoder Two-channelNoiseReduction Module 7,8,9Function SlotCard Cat. NoFuse Voltage SettingInternational TypeIMPORTANT SAFETY NOTICE IEC NOTICESGB F D I E S NL IMPORTANT - NOTE DE SECURITEModel CP65 HUM PROBLEMS3.Room lighting dimmer controls SCR-TYPE With CP65 FADER turned up and format 04 selected 2. Aligning the B-Chain SECTION AN OVERVIEW OF THE ALIGNMENT PROCEDURE1. Aligning the A-Chain and with a broad range of speakers. Accurate equalization requires the use of standardized acoustic measurement procedures Many loudspeakers used in theatres are far from ideal and require boosting of the low- and high-frequencyextremes in order to produce an approximation of the standard reference response curve. Bass and treble controls-centeredon the turnover points of typical loudspeakers-liftthe ends of the spectrum without the need for large amounts of narrow- band boost from the third-octavecontrols in the Cat. No. 64 cards. The third-octavecontrols are used for minor adjustments that are required to smooth the frequency response curve SECTION A-CHAINALIGNMENT Action a. Preliminary Proceduresa. Preliminary Procedures Notes Indicationa. Preliminary Procedures Notes A-ChainAlignment Proceduresa. Preliminary Procedures ActionAction b. Optical Preamplifier Adjustmentsb. Optical Preamplifier Adjustments Notes Indicationb. Optical Preamplifier Adjustments Notes A-ChainAlignment Proceduresb. Optical Preamplifier Adjustments Actionb. Optical Preamplifier Adjustments L L R R L L R RCAT NO b. Optical Preamplifier Adjustments NotesCAT. NO. 97 TEST FILM ActionIndicationn REPEATA-ChainAlignment Procedures OSCILLOSCOPE TRACESRTA DISPLAY b. Optical Preamplifier AdjustmentsA-ChainAlignment Procedures 12 ANDREPEAT b. Optical Preamplifier Adjustmentsb. Optical Preamplifier Adjustments CAT NOFOR PROJECTOR NO. REPEAT 1 → b. Optical Preamplifier Adjustments Notesc. Magnetic Preamplifier Adjustments Magnetic AlignmentMagnetic Alignment A-ChainAlignment Proceduresc. Magnetic Preamplifier Adjustments SECTION B-CHAINALIGNMENT bypass a. Setting Room Equalizationa. Setting Room Equalization Notes Actiona. Setting Room Equalization Notes Loudspeakers and Crossoversa. Setting Room Equalization ActionGeneral bypassAmplifiers a. Setting Room EqualizationAction B-ChainAlignment Proceduresa. Setting Room Equalization Notes Indicationa. Setting Room Equalization Notes REPEATa. Setting Room Equalization Actiona. Setting Room Equalization Notes B-ChainAlignment Proceduresa. Setting Room Equalization Actiona. Setting Room Equalization Notes Do not adjusta. Setting Room Equalization ActionAction a. Setting Room Equalizationa. Setting Room Equalization Notes IndicationL 14 → 21 R 14 → b. Adjusting L,C,R Gainb.Adjusting L,C,R Gain 22REPEAT79 dBC c. Setting Mono Gainc. Setting Mono Gain Notes ActionB-ChainAlignment Procedures d. Subwoofer Alignment Cat. Nod. Subwoofer Alignment Cat. No. Notes Actiond. Subwoofer Alignment Cat. No 90 dBCB-ChainAlignment Procedures Actiond. Subwoofer Alignment Cat. No FROMd. Subwoofer Alignment Cat. No ActionAction Select format 04 Dolby Stereo A-Typed. Subwoofer Alignment Cat. No REPEATd. Subwoofer Alignment Cat. No SAME ASd. Subwoofer Alignment Cat. No Actione. Surround Equalization Alignment Cat. No Re Se. Surround Equalization Alignment Cat. No Actione. Surround Equalization Alignment Cat. No ActionREPEAT e. Surround Equalization Alignment Cat. NoAction Action 88 dBCe. Surround Equalization Alignment Cat. No Action B-ChainAlignment Procedurese. Surround Equalization Alignment Cat. No Indicationmsec f. Adjustment of Surround DelayThumbwheel Switch Settingxx dBC g. Adjustment of Bypass Gaing. Adjustment of Bypass Gain Notes B-ChainAlignment Proceduresg. Adjustment of Bypass Gain FROM xx dBC -3dB yy dBCB-ChainAlignment Procedures g. Adjustment of Bypass Gain NotesPress the format 60 non sync switch h. Adjustment of Non-syncGainh. Adjustment of Non-syncGain Notes ActionAction h. Adjustment of Non-syncGainh. Adjustment of Non-syncGain Notes Indication5REPEAT PAGE 5-20STEP i. Adjustment of Mono Gain and Equalizationi.Adjustment of Mono Gain and Equalization Notes B-ChainAlignment Proceduresj. Final Checks Press the format 04 Dolby Stereo A-type switchJIFFY TEST FILM j. Final Checks NotesSECTION REFERENCE DIAGRAMS Cat. No. 222 Dual Noise Reduction Module INPUTS OUTPUTSPage Cat. No. 242 B-ChainFacilities Card Cat. No. 249 Power Supply Card Cat. No. 259 Transformer Module INPUTS OUTPUTSCat. No. 443 Control Logic Card +24V CP65 POWER DISTRIBUTION TABLECat. No +15VAPPENDIX A CHECKING PHASING OF SPEAKERS 10,000 Frequency in Hz5,000 20,0002.Cat. No. 327A Circuit Description APPENDIX C CP65M MONO INSTRUCTIONS1.Operation C.2 Schematic Cat. No. 327A A3C2984 revTerminal Block TB1 APPENDIX D BACKPLANE CONNECTIONS LISTCP65 Backplane Connections Terminal Block TB2D connector J18