Harman-Kardon-Citation_2-Service-Manual 电路图 维修手册.pdf

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1、RadioFans.CN 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 1 BASIC SPECIFICATIONS SUSTAINED POWER OUTPUT: 60 watts per channel. PEAK POWER OUTPUT: 130 watts per channel. HARMONIC DISTORTION: Less than 0.5%, 20- 20,000 cycles per second at 60 watts. Less than 0.1%, 20- 20,000 cycles per second at 20 watts. Unme

2、asurable at normal listening level. INTERMODULATION DISTORTION: Less than 0.5% at 60 watts. Less than 0.2% at 20 watts. Unmeasurable at normal listening level. FREQUENCY RESPONSE: 60 watts. 18- 40,000 cycles per second +0, -1.0 db. 20 watts. 12- 60,000 cycles per second +0, -1.0 db. 1 watt. 2- 80,00

3、0 cycles per second +0, -1.0 db. OUTPUT IMPEDANCE: 4, 8, and 16 ohms per channel. DAMPING FACTOR: Greater than 18. FEEDBACK Total 30 db. Achieved through multiple loops. HUM AND NOISE: Better than 90 db below 60 watts. POWER SUPPLY: Close B+ regulation through use of low Z silicon diode rectifier po

4、wer supply. SENSITIVITY: 1.5 volt RMS input for 60 watts. STABILITY: Unconditionally stable under any load. INPUT RECEPTACLES: One for each channel. One input for A.C. balance adjustment. CONVENIENCE RECEPTACLE: One A.C. convenience receptacle. CONTROLS: Four bias adjust controls. One for each outpu

5、t tube. Two A.C. balance controls. FUSE A.C. primary, externally accessible. CONSTRUCTION: Military terminal board construction with all components held to rigid tolerances. TUBE COMPLEMENT: Total 10 tubes, 5 semi-conductors. 6- 12BY7A pentodes; 4- KT88/6550 beam power pentodes, 4 silicon rectifier

6、diodes, and 1 selenium rectifier. POWER CONSUMPTION: 350 watts. DIMENSIONS: 16 wide x 9 high x 11 deep. WEIGHT: 60 lbs. FINISH: Charcoal brown and gold. RadioFans.CN 收音机爱 好者资料库 2 FEATURES Use of video output pentodes in all low level stages for exceptionally wide frequency response and low distortio

7、n. Output stage consists of two KT88/6550s per channel, conservatively operated in fixed bias, distributed load circuit. Multiple feedback loops for increased degree of usable feedback to greatly lower distortion without sacrificing stability. 30 db overall. Low internal impedance power supply consi

8、sts of 4 Silicon Rectifier Diodes, choke, and heavy duty electrolytics with potted power transformer for close regulation. Extended frequency response. Two octaves above and below the normal range of hearing for smooth, transparent sound. Absolute stability with any load! Output transformers designe

9、d specifically for this amplifier to exacting specifications. High power output at the extreme ends of the range enables the amplifier to effortlessly drive any of todays inefficient speakers at any power level. High power rating insures flawless, transparent reproduction at low listening levels. Mi

10、litary construction for neat and professional appearance. Bias meter to adjust individually the plate current of each KT88/6550 for proper balance and lowest distortion. This insures optimum performance even after aging of the output tubes. Unique packaging of components to facilitate identification

11、 and to reduce assembly time. Use of special glass resistors and heavy duty capacitors for long life and trouble free performance. All components are conservatively rated. 3 CITATION II CURVES 4 5 INTRODUCTION This new Citation basic amplifier kit represents the culmination of extensive research and

12、 experimentation in the technique of kit design. It is meant to satisfy the aspirations of those who insist on nothing short of perfection itself. The keynote is unparalleled performance and there has been no compromise made in the design of this magnificent instrument. Although the Citation II will

13、 perform satisfactorily with any high quality preamplifier, it is strongly recommended it be used with the Citation I or Citation IV stereo preamplifiers control center for optimum performance. The Citation I and IV match the superb frequency response and distortion specifications of the Citation II

14、 resulting in uncompromising performance. This instruction manual is written in simple, nontechnical language and if you will take the time to read it thoroughly before starting the actual construction of this kit, your work will be easier and far more accurate. Additional information may be obtaine

15、d by carefully studying the large fold-out diagrams supplied with this manual. These may be attached to the wall opposite your workbench for easy reference. After studying the manual, work slowly and carefully. After every ten or fifteen steps, go back over your work to check for possible errors. Th

16、is will insure proper construction and will afford you the feeling of satis- faction upon completing an amplifier that performs perfectly the first time it is connected. KEEP THIS INSTRUCTION MANUAL AVAILABLE AT ALL TIMES FOR IT CONTAINS IN- DISPENSABLE TECHNICAL AND SERVICE INFORMATION. TECHNICAL D

17、ESCRIPTION Extensive listening studies reveal that the behavior of a high fidelity amplifier several octaves above and below the normal range of human hearing distinctly colors the reproduced sound. It has been determined that an amplifier having a wide frequency response at useable power levels bel

18、ow 5 cycles has a tight and clearly defined low end, particularly in the 40-100 cycles region. A similar condition applies to the performance of an amplifier in the high frequency spectrum. If an am- plifier limits its high frequency response to slightly above the limit of audibility, it may have a

19、tendency toward strident reproduction and poor differentiation of instruments in the high overtones. Conversely, an amplifier which has a frequency response beyond 100,000 cycles without evidence of ringing or instability with reactive loads will offer clean, transparent tone qualities in the higher

20、 frequencies with excellent instrument separation. It is for this reason as well as other considerations that conventional power amplifier design has been by- passed in the general design concept of this basic amplifier. Current power amplifier design is based upon “single loop” feedback techniques,

21、 and linearization is ob- tained by overall feedback from the voice coil terminals to the cathode of the input tube. Stability problems limit this application to 20- 26 db of useable feedback, which represents a 101 to 201 reduction in distortion. Careful listening evaluation of amplifier performanc

22、e proves conclusively that extremely stable amplifiers with higher degrees of feedback provide a noticeable improvement in sound quality and a definite reduction in listening fatigue. This improvement can be attributed to lower harmonic and intermodulation distortion prod- ucts, more linear phase ch

23、aracteristics, and improved transient response. A “multiple loop” approach toward increasing the degree of useable feedback is the most logical approach to lower distortion without sacrificing stability. These “multiple loops” become additive if their ratio is adjusted to the relative degree of dist

24、ortion produced. Thus, if one stage has twice the distortion of another, it should have twice as much feedback around it. Experiment has shown that the equivalent of 30 db overall feedback is safely reached by this approach. It is essential to have a well regulated power supply in order to maintain

25、clean transient response. The power supply of this amplifier incorporates four Silicon Rectifier Diodes, which together with extremely low copper loss in the power transformer provides regulation equivalent to that of a regulated supply. Leakage inductance in the output transformers has been kept to

26、 an absolute minimum, and the distributed capacitance of the primary halves have been carefully balanced against each other to maintain the natural resonances of the output 6 transformers well above 200,000 cycles. The combined use of these special output transformers in conjunction with video pulse

27、 amplifier techniques and multiple feedback loops have enabled us to achieve the exceptionally wide frequency response of two octaves above and below the normal range of human hearing. This design employs 2-KT88/6550 beam power pentodes in each channel, driven by video power pentodes used convention

28、ally in pulse amplifiers and wide band industrial equipment such as computers. All low frequency coupling networks have been inserted into internal feedback loops, thereby reducing phase distortion to an absolute minimum in the subsonic region. At the same time the high frequency response of the amp

29、lifier, exclusive of the output transformer, is flat to the megacycle region. From the moment you turn this amplifier on and the stylus touches the record with an assured “thump”, you will know you have constructed an exceptional instrument. Critical listening tests will reveal subtleties in your re

30、cords and tapes you never knew existed, and each performance will prove to be a new experience for you. UNPACKING Set aside ample room on your workbench to unpack the contents of this kit. Open the carton carefully and place all of the components on your workbench, separating them into their respect

31、ive categories. Handle all parts with care, for they may become damaged through carelessness. Check the contents of the carton and folds of the packing material before discarding it. After all of the parts have been unpacked, check them against the master parts list in this manual to make certain al

32、l parts are present and are correct as to type and value. Whenever possible, the values are stamped on the outside of the parts to facilitate identification. PLEASE NOTIFY YOUR DEALER IMMEDIATELY IF A SHORTAGE OR ERRONEOUS PART IS DISCOVERED. In the event of visible shipping damage, notify your deal

33、er at once. If the kit was shipped to you, notify the transportation company without delay. Harman-Kardon will cooperate with you in such instances, but please note that only you can recover from the carrier for damages incurred during shipping. To help us expedite delivery to you, it may occasional

34、ly be necessary for us to make minor part substitutions. Before these substitutions are made, they are thoroughly checked to be certain that the replacement is equal to or superior to the original component in every respect. For example, a 50 volt capacitor may be substituted for a 25 volt unit. In

35、some instances, a 5% tolerance component may be substituted for a 10% unit. This would provide a component with closer tolerances than required. In every case, these substitutions will not affect the per- formance of the unit. CONSTRUCTION INFORMATION Tools Required Only standard tools are required

36、for the proper assembly of this kit. The most important and frequently used tool will be the soldering iron. It should therefore be a good one. A pencil type iron between 50 and 80 watts or a solder gun up to 100 watts is recommended. You will also require a long-nose pliers, diagonal cutters, screw

37、driver, sharp knife, solder (rosin core only), and an adjustable wrench. An ohmmeter could be of value but is not essential. Soldering Technique Good solder connections are essential for the proper operation of this instrument. An improperly soldered connection or a “cold” solder joint can cause con

38、siderable difficulty and is extremely hard to locate. If you have little or no experience with soldering, it is suggested you read the following section carefully before proceeding with the construction of the kit. Practice your soldering on an old terminal strip or tube socket until you are certain

39、 you can attain a workable degree of skill. Soldering is not difficult. Merely observe the following rules and precautions: 7 1. USE ONLY ROSIN CORE (NON-CORROSIVE) SOLDER! The solder you purchase should be clearly labeled for radio and television use. The usual composition is 60% tin and 40% lead i

40、ndicated on the package label as 60/40. Do not use so-called non-corrosive paste. This compound is highly corrosive when heated and will destroy the insulation value of non-conductors and will quickly lead to erratic or degraded performance. It has been our experience that the following solder offer

41、 the best results. Alpha, Cen-tri-core energized rosin 60/40 alloy .062 dia. Bow, AE 16 rosin core 60/40 alloy .062 dia. Kester, “44” rosin core 60/40 alloy. Kester, “Rosin Five” core 60/40 alloy. Multi-core, Solder #13 SWG (5 core) Flux 364 (rosin) 60/40 alloy. 2. Use a high quality soldering iron

42、in the 50-80 watt range. You may choose either the standard diamond or chisel tip. Always keep the tip clean and properly tinned in accordance with the manufacturers instructions. 3. All terminals and leads must be free from dirt, wax, and corrosion, for solder will not adhere to dirty surfaces. Car

43、efully scrape all terminals and leads which are not clean before applying solder. 4. Solder alone cannot be relied upon for strength. A good mechanical connection must always be made before applying solder. Tinning the leads on resistors and condensers is not always necessary, but is advisable for i

44、t helps the solder adhere more readily to the connection. 5. To solder properly, apply the soldering iron to the joint until the joint heats sufficiently to melt the solder. Apply the solder and hold the iron on the connection until the solder flows freely around and into the connection. Merely melt

45、ing drops of solder onto the connection is not satisfactory and will result in faulty connections. 6. The general appearance of a connection can indicate if it is properly made. A “cold” solder joint presents a dull and pitted or grainy appearance. A good solder connection should have a bright and s

46、mooth appearance. When in doubt as to the condition of a connection, it may be tested by moving the leads slightly to determine if they are loose. Always apply fresh solder when correcting a loose or “cold” solder connection. As a rule, simply reheating the defective joint will not properly do the j

47、ob. 7. When using your soldering iron, avoid applying excessive heat, as this can result in damage to certain components. When soldering a joint having a small component connected to it, the part may be protected from excessive heat produced by the iron by grasping the lead between the joint and the

48、 component with a long-nose pliers. The pliers will then conduct most of the heat away from the component, preventing overheating and damage. 8. Do not use excessive solder when making a connection. Use only enough solder to cover all leads and to insure a tight connection. Excessive solder may resu

49、lt in the formation of shorts between adjacent terminals, particularly on tube sockets and switch terminals. 9. The step-by-step instructions tell you when to solder and when not to solder a connection. When the letters “NS” appear after or during a step, simply wrap or crimp the lead to the terminal and proceed to the next step. When all connections have been completed to this terminal, the solder designation “S” will follow. 8 WARRANTY OF HARMAN-KARDON CITATION KITS For a period of