HarmanKardon-Citation2-pwr-sm1维修电路原理图.pdf

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1、RadioFans.CN RadioFans.CN 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. Unmeasurable at normal lis

2、tening 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- 80,000 cycles per second +0

3、, -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 power supply. SENSITIVIT

4、Y: 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 output tube. Two A.C. balan

5、ce 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 diodes, and 1 selenium

6、 rectifier. POWER CONSUMPTION: 350 watts. DIMENSIONS: 16 wide x 9 high x 11 deep. WEIGHT: 60 lbs. FINISH: Charcoal brown and gold. RadioFans.CN 2 FEATURES Use of video output pentodes in all low level stages for exceptionally wide frequency response and low distortion. Output stage consists of two K

7、T88/6550s 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 consists of 4 Silicon Rectifier Diodes

8、, 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 designed specifically for this amplifier

9、 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. Military construction for neat and

10、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 and to reduce assembly time. Use

11、 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 experimentation in the technique

12、 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 perform satisfactorily with any

13、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 resulting in uncompromising perf

14、ormance. 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 obtained by carefully studying the large

15、 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. This will insure proper constructio

16、n 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 DESCRIPTION Extensive listening st

17、udies 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 below 5 cycles has a tight and clear

18、ly 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 tendency toward strident reproduc

19、tion 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 frequencies with excellent instr

20、ument 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, and linearization is ob- tained

21、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 performance proves conclusively that extrem

22、ely 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 characteristics, and improved trans

23、ient 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 distortion produced. Thus, if one sta

24、ge 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 clean transient response. The pow

25、er 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 an absolute minimum, and the dis

26、tributed 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 amplifier techniques and multipl

27、e 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 conventionally in pulse amplifiers and wide

28、 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 amplifier, exclusive of the output t

29、ransformer, 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 records and tapes you never knew ex

30、isted, 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 respective categories. Handle all parts

31、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 all parts are present and are corre

32、ct 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 dealer at once. If the kit was shippe

33、d 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 occasionally be necessary for us to make mi

34、nor 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 some instances, a 5% tolerance co

35、mponent 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 for the proper assembly of this k

36、it. 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, screwdriver, sharp knife, solder (rosi

37、n 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 considerable difficulty and is extre

38、mely 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 you can attain a workable degree

39、 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 indicated on the package label as

40、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 the best results. Alpha, Cen-tri

41、-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 in the 50-80 watt range. You may

42、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. Carefully scrape all terminals and l

43、eads 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 it helps the solder adhere more re

44、adily 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 melting drops of solder onto the conn

45、ection 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 smooth appearance. When in doubt a

46、s 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 job. 7. When using your soldering

47、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 component with a long-nose plier

48、s. 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 result in the formation of shorts bet

49、ween 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 90 days following the original d