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INSTRUCTION MANUAL
for the
JC-2 PREAMPLIFIER
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IMPORTANT Please read these instructions carefully and completely before operating the JC-2 preamplifier. A great deal of effort went into the design and construction of this precision device. Understanding its functions will enable you to use it to fullest advantage.
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INSTRUCTION MANUAL for the JC-2 PREAMPLIFIER 1. INTRODUCTION The MARK LEVINSON JC-2 PREAMPLIFIER is the distillation of years of scientific research and careful listening. The amplification circuitry designed by John Curl combines the advantages of class A, completely complementary push-pull operation, high open-loop bandwidth, and low feedback configurations in order to approach perfect solid-state pre- amplification of the most demanding recorded musical material. Hand- matched active an
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3.2. Power Supply Connection The power supply for the JC-2 is mounted in a separate chassis to eli- minate hum pick-up. Check the voltage the power supply comes a cable with a three power supply label to be sure they correspond to the voltage of the power source being used. From one end of the power supply comes a cable with a three prong AC plug on the end of it. Connect this end to a wall outlet, using a ground adapter plug if your wall outlet will not accept three prongs. From the other en
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TAPE 1/TAPE 2 - selects either tape input 1 or tape input 2 for the input/ monitor switch. MONO/STEREO - selects either a mono or a stereo mode at the main outputs. HIGH/LOW - selects either 21dB gain (HIGH) or 11dB gain (LOW) in the output stage. Line level inputs should generally be used only with the low gain setting. Low level phono inputs can be used with either HIGH or LOW depending on the output level of the phono cartridge. If when using the low gain position, the output level control is
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UNIVERSAL PHONO PLUG-IN CARDS System: Gain: Overload: 1kHz 20kHz A Two UP-1A cards are normally sup- 36dB 100mv 900mv plied with the JC-2 unless other- wise specified. This system accepts Input impedance: 47kOhms. B The UP-1B system offers lower 30dB 220mv 1.6v sensitivity but increased head- room for the highest output magne- tic phono cartridges. C This set provides exact equalization for the Brüel & Kjaer series of cartridge measurement records. Information on request. D This system includ
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6. SPECIFICATIONS Phono Section: Gain* 1kHz 36dB OVERLOAD POINT* 1kHz 100mv min. *(see also Section 5) MAXIMUM OUTPUT 18Hz to 20kHZ 6v min. CHANNEL TRACKING 18Hz to 20kHz .5dB ( .2 typ.) FREQUENCY RESPONSE -1.5dB down at 18Hz, 30kHz min. NOISE 18Hz to 20kHz: ASA "A" weighted below 10mv, inputs shorted 85dB 90dB min. below 10mv, 600ohms load 83dB 88dB INPUT IMPEDANCE 47kOhms* RECOMMENDED LOAD 10kOhms or higher OPEN LOOP BANDWIDTH 1500Hz min. SLEW RATE 20V/microsecond NOISE (JC-1SM) below 1mv i
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7. WARRANTY All MARK LEVINSON products are guaranteed for five full years from date of purchase. Parts and labor will be furnished free of charge. The manufacture assumes no responsibility for damaged or abused equipment and reserves the right to determine cause of defects. IMPORTANT: Addendum to Section 4 An output coupling selector switch is located between the line ampli- fiers on the main circuit board. When switched to the right (factory set position) the line outputs are AC coupled for
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NEW DEVELOPMENTS IN THE JC-2 JC-2 Preamplifiers starting with serial number 2148 differ from previous units. They are equipped with lemo connectors, a new power supply (PLS-150), two phono inputs and new phono plug-in cards. PHONO SECTION The standard systems are now A3, D5 and d6. The plug-in cards contain a two-station program switch for selection of input and gain characteristics. System Rocker Switch Function Open Closed A3 1 input impedance 100k 50k 2 gain 30dB 40dB D5 1 CRC* CRC out CRC i
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TONEARM CABLE ADAPTOR From an effort to simplify the connection of existing turntables to MLAS Pre- amplifiers fitted with Lemo connectors, we have developed the CA-1 cable adap- tor. The CA-1 is a solid block of aluminum 2X2X .75" machined to exact toler- ances and finished in our standard brushed black anodized surface. It replaces the phono connectors of any existing tonearm cable and allows connections to our preamps with an LL (Lemo to Lemo) cable set. (see page 11 of our 12-1-76 notice. )
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INSTRUCTIONS FOR ASSEMBLING THE CA-1 CABLE ADAPTOR 1. The CA-1 may be mounted to a shelf, cabinet, or turntable base with one wood screw. This keeps fragile tonearm leads from breaking or flexing. 2. Use LL-.6 or LL-3 cables to connect with your JC-2 or LNP-2 preamplifier. 3. Cut the phono connectors from the tonearm leads, nothing which wire is left and which is right. 4. Strip the ends about 1/2" so that a center conductor and shield are prepared for each end. 5. Insert the wires through the s
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PLS-150 POWER SUPPLY SYSTEM JC-2 preamplifiers with Lemo connectors are equipped with the PLS-150 Power Supply. The PLS-150 Power Supply is considerably larger and heavier than the ones delivered with previous units. We recommend that it be positioned with the cable end facing the wall and the front plate facing forwards. In this way, the two LED' s will be visible. these lights indicate that the power supply is receiving the correct AC voltage and is delivering the correct DC voltage. If the AC
