Shure_55_Data_Sheet 电路图.pdf

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1、SHURE BROTHERS INCORPORATED Microphones and Acoustic Devices 225 WEST HURON STREET : CHICAGO 10, ILLINOIS PHONE DELAWARE 7-4550 : CABLE: SHUREMICRO DATA SHEET D A T E :FEBRUARY, 1951 S U B J E C T :Model 55 Multi-Impedance Unidyne Dynamic Microphone. 55 Multi-Impedance Unidyne Microphone (Super-Card

2、ioid Uni-directional Moving-CoilDynamic) General:Model 55 is-a super cardioid unidirectional moving coil dynamic microphone providing wide-range high quality reproduction of sound. The true unidirection- al characteristic of the Unidyne, obtained by the uni- phase principle* provides highly satisfac

3、tory operation under adverse acoustic conditions where a conventional microphone would be practically useless. (See “Acoustic Considerations”). The microphone has a specially designed moving system containing a new type moving-coil element, operating in conjunction with a high flux magnet in the mag

4、netic circuit providing high efficiency and smooth peak free response from 40 to 15,000 cycles. The rear response is down approximately 15 db due to the uni- phase unidirectional acoustic network. The case is modern in design with attractive stream- lining and grille treatment. The head tilts throug

5、h an angle of 90 to permit aiming at the source of sound for best pickup. A built-in cable connector is provided and a 20 ft. shielded rubber-jacketed cable with microphone plug attached is included. Applications:Model 55 is suitable for high quality public address, broadcasting, recording and simil

6、ar appli- cations. The true unidirectional characteristic of the Unidyne provides an easy solution to the feedback problem in reverberant locations, facilitates orchestral placement, permits best utilization of space in small broadcast studios, and allows practically complete ex- clusion of unwanted

7、 noises. The swivel allows the head to be tilted through an angle of 90 permitting the micro- phone to be aimed at the source of sound. Installations:All microphones have the standard 5/8-27 thread and may be mounted on any conventional desk, banquet, or floor stand. When long lines are used, care s

8、hould be taken that the cable does not parallel A.C. power lines for long distances to avoid A.C. hum induction. Connections:The Model 55 Microphone is of the multi-impedance type. Model 55 may be worked directly into a 30-50 ohm line, a 150-250 ohm line, or a high im- pedance input. Selection of th

9、ese impedances is accom- plished by changing the position of the switch at the rear of the microphone. The switch positions are marked L for low impedance (30-50 ohms), M for medium imped- ance (150-250 ohms), and H for high impedance (35,000 ohms). line length is practically unlimited, since neithe

10、r response or level is appreciably affected by reasonable lengths of line. The high impedance position on the Model 55 Microphone may be used with any crystal microphone amplifier or other amplifier with an input impedance of 100,000 ohms or more (See Fig. A-3). For best high frequency response, the

11、 total cable lengths should not ex- ceed 25 feet; longer cable lengths may be used with some loss of high frequency response. The additional loss at 5000 cycles is of the order of 2.5 db for an additional 25 ft. length of cable (50 ft. total) and 6 db for an additional 50 ft. length (75 ft. total).

12、If the Model 55 Microphone is used in the high impedance position, single conductor shielded cable may be used to provide ad- ditional cable lengths; also, the two-conductor cable fur- nished with the Microphone may be replaced with single conductor shielded cable, if the microphone is intended to o

13、perate directly into high impedance (grid) input only. In this instance, the number one pin and the number two pin of the cable plug must be shorted together and con- nected to the shield of the cable. The shield, chassis or amplifier ground should be securely connected to a water pipe or similar gr

14、ound to prevent shock hazard during operation of amplifying system. The low andmedium impedance positions of the Model 55 may be fed into a standard low or medium impedance input amplifier (Fig. A-1), or into an amplifier with high impedance input (Fig. A-2). In the latter case, Shure Model A86A Cab

15、le-Type Transformer is available for coupling the low impedance line to the amplifier input. The double winding primary of the Shure Model A86A Cable type transformer permits coupling either a 30-50 ohm line or 150-250 ohm line to high impedance input. In circuits using the grid leak type of bias on

16、 the input tube, it may be desirable to use a .01 mfd. or larger condenser between the microphone and the input grid circuit. Operation:The microphone should be placed in its operating position before turning up the volume controls of the amplifier. Jarring or excessive moving of the in- strument sh

17、ould be avoided while the system is in opera- tion in order to prevent the spring-suspended microphone unit from touching the inside of the case and producing undesirable noises. The low and medium impedance positions are recom- mended where long cable lengths are required or under conditions of sev

18、ere hum disturbances. The permissible *Patented by Shure Brothers Inc. No special precautions beyond ordinary care are necessary in the operation of the Model 55 Dynamic microphone. It will operate efficiently and dependably under all ordinary conditions in hot and cold climates. To retain the full

19、strength of the highly efficient permanent Copyright, 1951 Shure Brothers, Inc.( O v e r ) Printed in U.S.A. RadioFans.CN 收音机爱 好者资料库 magnet and to maintain alignment of the structure, dropping or other severe mechanical shocks should be avoided. Acoustic Considerations: The expression super cardioid

20、 response simply means that the horizontal polar characteristic ap- proximates a super cardioid. There is a wide, useful pickup angle at the front of the microphone while the response at the sides is down 6 db from the front response. The rear response in practical super cardioid microphones is down

21、 of the order of 15 db from the front side response. The Unidyne fulfills these requirements over a broad range of frequencies. The true unidirectional characteristic of the Unidyne should not be confused with the relatively slight directional effect at high frequencies only which can be produced by

22、 baffle effects in the conventional pressure microphone. Frequency- Cycles per Second Fig. B. Response-Frequency Characteristic Model 55 Microphone. 27A31. 2-51. The result of this unidirectional characteristic is a complete elimination of acoustic feedback at volume levels which would causeconsider

23、able feedback with conventional semidirectional microphones. In practically all cases it is possible to increase loud- speaker levels when a Unidyne is installed. By directing the dead side (rear) of the microphone towards the audience or other source of interfering sound, pickup can be concentrated

24、 on the desired source. Reverberation energy pickup is decreased approximately two-thirds. The microphone can be placed close to reflecting sur- faces without objectional effects if the rear side of the microphone is toward the reflecting surface.This is particularly valuable in small broadcast stud

25、ios. It is desirable to experiment with micro- phone placement and orientation in order to secure the greatest benefits from the unidirectional characteristic. Specifications 1000 C.P.S. Response: Model 55 L Position: Open Circuit Voltage Level . . . . . . . . . . . . .-84.1 db.( * ) Loaded With 40

26、Ohms . . . . . . . . . . . . . . . . . .-90.1 db.( * ) Power Level Into 40 Ohms . . . . . . . . . . . . .-56.1 db.( * * ) RMA Microphone Rating GM (Sensitivity) .-149.8 db.( * * * ) Model 55 M Position: Open Circuit Voltage Level. . . . . . . . . . .-76.8 db.( * ) L o a d e d W i t h 2 5 0 O h m s.

27、. . . . . . . . . . . . .-82.8 db.( * ) Power Level Into 250 Ohms. . . . . . . . . . . .-56.8 db.( * * ) RMA Microphone Rating GM (Sensitivity) .-148.6 db.( * * * ) Model 55 H Position: Open Circuit Voltage Level . . . . . . . . . . . .-57.5 db.( * ) Loaded With 100,000 Ohms . . . . . . . . . . . .

28、. . -60.1 db.( * ) RMA Microphone Rating GM (Sensitivity) .-153.7 db.( * * * ) ( * )0 db. = 1 Volt Per Dyne Per Sq. cm. ( * “ )0 db. = 1 Milliwatt with 10 Dynes Per Sq. cm. ( * * * )RMA Standard SE-105 Aug. 1949. Recommended Load Impedance: Model 55 L Position 30-50 Ohms. Model 55 M Position 150-250

29、 Ohms. Model 55 H Position 100,000 Ohms or More. M O D E L 5 5 C o d e W o r dR U M U L Net Wt. Less Cable2-3/4 Ibs. Shipping Weight4 Ibs. Cable 20 ft. Two-Conductor Height, Overall( a ) * 7-25/32 Height, Case( h ) *4-7/16 Width ( b ) * 3-3/16 Thickness ( c ) * 3-9/16 Finish Satin Chrome *See Fig. C

30、. Guarantee: Each microphone is guaranteed to be free from electrical and mechanical defects for a period of one year from date of shipment from factory, provided all instructions are com- plied with fully. In case of damage, return the microphone to the factory for repairs. Our guarantee is voided

31、if the microphone case is opened. MODEL 55 Architects Specification The microphone shall be a dynamic type microphone with a frequency range of 50 to 15,000 c.p.s. This unit shall have a super-cardioid pattern with nulls located at approxi- mately 130 and 230. The cancellation at the nulls shall be

32、at least 10 db. over the complete range of audio-frequency. The microphone shall be equipped with a three-position im- pedance change switch for adjusting the microphone rating impedance to 38, 150 or 40,000 ohms. The microphone rating GM (sensitivity) at 1000 c.p.s. shall be within 3 db. of the fol

33、lowing levels: L position of switch -149.8 db. M position of switch -148.6 db. H position of switch -153.7 db. RMA Standard SE-105 August 1949. The microphone shall be provided with a swivel adjust- able from 0 to 90 and it shall have a detachable cable con- nector. The microphone will mount on a stand having a 5/8 -27 thread. The overall dimensions shall be 7-25/32 1/4 inches in height, 3-3/16 1/8 inches in width and 3-9/16 1/8 inches in thickness. RadioFans.CN 收音机爱 好者资料库