Shure-M62v preamp 电路图.pdf

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1、222 HARTREY AVE EVANSTON, ILL. (60204) U.S.A. DATA SHEET MODEL M62V AUDIO LEVEL CONTROLLER AREA CODE 312/328-9000 CABLE SHUREMICRO MODEL M62V AUDIO LEVEL CONTROLLER GENERAL: The “Level-Loc” Audio Level Controller is basically a low noise preamplifier with unity gain from micro- phone level in to mic

2、rophone level out or 60 db of voltage gain from Hi Imp. microphone level in to Aux. Output. The input and microphone level output contain matching transformers so either high or low impedance may be selected. In addition, a high impedance Aux. Output is provided capable of driving any high im- pedan

3、ce amplifier, mixer or tape recorder input re- quiring 1 volt or less. This preamplifier has the addi- tional capability of reducing its gain as the input signal increases, thereby ho/ding the output signal constant. After a predetermined input level is reached (threshold) the output level is “Locke

4、d”, that is, it remains constant even if the input signal increases by as much as 100 times (40 db). This reduction in gain, which results in a constant output level, is obtained without introducing significant distortion or transients into the program material. The DISTANCE SELECTOR switch determin

5、es the input level at which gain reduction (Level-Lot action) begins. An INPUT LEVEL CONTROL is also provided that: 1. Can be used as a vernier control to allow fine adjustment of input threshold between the preset threshold levels selected by the DISTANCE SELECTOR switch. 2. Can act as an input att

6、enuator for signals that are higher than normal microphone levels. Such inputs may be: signals from microphones used very close to the mouth, outputs from preampli- fiers, line amplifiers, tuners or tape recorders. The Audio Level Controller: ? Reduces blasting or large volume increases when a speak

7、er or entertainer varies his dis- tance and position from the microphone. ?Upgrades tape-recording systems and the Audio portion of Video Tape Recorders, by controlling the maximum signal level being fed to the re- corder. This prevents distortion and overloading of the tape recorder which might be

8、caused by “close talking” the microphone, or by very loud vocal or musical passages. OUTPUT INPUTHi Imp. Mic.Lo Imp. Mic.Aux. Output Hi Imp. Mic.Unity-20 db+60 db Lo Imp. Mic.+20 dbUnity+80 db Copyright 1969, Shure Brothers Inc. 27A823 (JI) ?Permits any number of microphones to be used in a paging s

9、ystem or conference arrangement, without setting the level for each individual microphone. (For paging systems only low impe- dance microphones with normally open switches should be used.) Any number of these micro- phones may be operated in parallel across the low impedance input of the M62V, the A

10、udio Level Controller will automatically set a fixed maximum paging level that cannot be exceeded. SPECIFICATIONS Input Impedance (below threshold): High Impedance: 50 K ohms Low Impedance: 300 ohms (for 25 to 600 ohm sources) Input Levels: High Impedance: microphone level to 10 volts max. (using in

11、put level control) Low Impedance: microphone level to .2 volt max. (using input level control) Output Impedance: High Impedance Microphone Level: 3.3 K ohms Minimum recommended load: 5 K ohms Low Impedance Microphone Level: Less than 50 ohms Minimum recommended load: 25 ohms Aux. Output: 10 K ohms.

12、Minimum recommended load: 10 K ohms Gain Characteristics: Below threshold, Input Level control Maximum (10); measured from input to output : Frequency Response: 2 db 40 to 20,000 Hz Printed in U.S.A. RadioFans.CN 收音机爱 好者资料库 Maximum Output Noise (high-impedance microphone output), in db below 1 volt:

13、 300-20,000 Hz30-20,000 Hz (Noise)(Hum and Noise) Lo Imp. input 150 ohm Termination -103 db Hi Imp. Input -95 db 33 K ohm Termination -104 db Distortion (any level of regulation): 3% maximum THD. -95 db Dynamic Characteristics:Fast attack, moderate re- covery, fixed. Attack: For a 20 db step increas

14、e above threshold, gain is within 2 db of final value in 500 microseconds. Recovery: For a 20 db step decrease to threshold, gain is within 2 db of final value in 700 milliseconds. Battery Life: Approximately 200 hours. Dimensions: See Figure 5. Net Weight: 2.2 Ibs. Input Connections: The Cannon-typ

15、e receptacle marked INPUT is designed for either low (25 to 600 ohms) or high impedance (50,000 ohms) inputs. The impedance is selected by a slide switch above the input receptacle. The unit is not recommended for use with crystal or ceramic microphones. The input receptacle is a female Cannon-type

16、XL-3-13 (uses XL-3-12 mate, Shure Part No. 95A55, or XL-3-12C mate, Shure Part No. 95A227). See Figure 2a for low and high impedance connections to re- ceptacle. INPUT PLUG CONNECTIONS FIGURE 2a AUX. INPUT POWER: This jack is used as a power input when using the power supply of a Shure M67 or M68 Se

17、ries Mixer or M63 Audio Master.In this case, the battery should be disconnected. A special connecting cable is provided to connect the AUX. INPUT POWER jack on the M62V to the Accessory 28 V. D.C. jack on the M68 Mixer or to the Pos. (red) 30 V. D.C. jack on the M67 Mixer or M63 Audio Master. In ord

18、er to utilize A.C. current, the use of a 9 volt D.C. Battery Eliminator is suggested. There is a pro- vision in the battery compartment cover that will allow using a 9 V. D.C. Battery Eliminator to power the M62V. The Battery Eliminator cable is to be slipped into the split rubber grommet on the cov

19、er of the battery com- partment. To secure cable, rotate grommet turn. Connection is to be made using the same battery clips that normally connect to the 9 volt battery. Output Connections: The receptacle marked MIC.(Note: If a Shure M68, M67 or M63, or a Battery OUTPUT is a dual impedance output se

20、lected by theEliminator is to be used, first remove the battery.) Page switch above the receptacle. This output is designed to work into a 25 to 600 ohm microphone line or microphone input, or into a high impedance amplifier or tape recorder microphone input. The receptacle is a male three-pin Canno

21、n type XL-3-14 connector (uses XL-3-11 mate, Shure Part No. 95A38, or XL-3-11 C mate, Shure Part No. 95A176). See Figure 2b for microphone level output receptacle connections. MICROPHONE OUTPUT PLUG CONNECTIONS FIGURE 2b The receptacle marked AUX. OUTPUT is a phono pin jack which accepts a standard

22、phono pin plug. This output is designed to work into a high-impedance (10 K ohm or greater), high level input of a mixer, preamplifier, amplifier, or tape recorder. This output may be connected to the AUX. INPUT of an M68 Series Mixer, the HIGH-LEVEL INPUT of an M63 Audio Master or the line input (b

23、ridging) of an M67 Professional Microphone Mixer. The static characteristics of the high-level AUX. OUTPUT are shown in Figure 1b. This output provides a constant 1 volt level (with a 47 K ohm load) when- ever the input level is above threshold. Below thres- hold it provides approximately 60 db of g

24、ain over the Hi-Imp Mic. Level Input. NOTE: This output is disabled when the MASTER CONTROL switch is set to “Bypass.” Battery and Auxiliary Power Connections: The battery to power the M62V is shipped with the unit but must be installed. Install as follows: 1. Remove Battery Compartment Cover by rem

25、oving the lower slotted screw holding cover, loosening the upper screw, and sliding the cover down. 2. Snap battery into clips provided. 3. Replace Battery Compartment Cover and tighten screws securely. Battery Replacement-Use Eveready type 216 or 222, or equivalent 9 V. Battery. 2 RadioFans.CN 收音机爱

26、 好者资料库 CONTROLS AND OPERATION MASTER CONTROL: With the MASTER CONTROL in the “Bypass” position: The battery is disconnected from the “Level-Loc” circuitry and thus the level-controlling action of the M62V is inoperative. The AUX. OUTPUT is disabled. The input to the M62V is switched directly to the

27、MIC. LEVEL OUTPUT so in this “Bypass” con- dition the unit can serve as a microphone line matching transformer. With the MASTER CONTROL switch in the “Level- Loc” position, the unit is energized, its level-con- trolling capability operates, and the AUX. OUTPUT is available. DISTANCE SELECTOR: When t

28、he M62V is being fed directly from a micro- phone source, best results are usually obtained when the DISTANCE SELECTOR is set for the actual dis- tance the performer is located from the microphone. For example: a singer or soloist standing nominally 6 inches from a microphone would require a setting

29、 of “6 or Less” on the DISTANCE SELECTOR. A panel discussion where the speaker(s) may be any distance up to 18 inches or more, would require a setting of “18 or More” on the DISTANCE SELECTOR. When recording in quiet surroundings, the 18 setting of the DISTANCE SELECTOR may be used to obtain maximum

30、 control of the recorded level. This is especially advantageous in recording sound sources where the volume is not predictable. If under these conditions, very loud program material or high sensi- tivity microphones result in distortion, the DISTANCE SELECTOR may be changed from the “18 or More” pos

31、ition to the “12” or “6 or Less” position. (Each position represents a 6 db change in threshold.) In extreme cases of overload the INPUT LEVEL CON- TROL can be reduced (See INPUT LEVEL CONTROL) When using the Audio Level Controller in a public- address system, with the Master Control in the “Level-

32、Loc” position, turn up the volume control on the public-address amplifier to that point where the system is just below the threshold of feedback with no one speaking into the microphone. In this manner, the total system gain is reduced as signal above threshold is applied, and the system is more sta

33、ble during loud parts of the performance. Should accidental feedback occur, the M62V will prevent it from becoming “ear- splitting” or damaging the loudspeakers. The Level-Lot action may be demonstrated by switching from the LEVEL-LOC to the BYPASS position of the MASTER CONTROL, provided the MIC. L

34、EVEL OUTPUT is being used. Figure 1 illustrates the static input-output character- istics of the Audio Level Controller, with the INPUT LEVEL CONTROL at maximum and Hi Impedance in- put and Hi. Imp. microphone level output, (Note: there is a 20 db level difference between Hi Imp. and Lo Imp. A high

35、impedance to low impedance transformer, as used in the Input or Output of the M62V, gives a 20 db reduction of voltage gain.) Page 3 As an example, consider the Distance Selector switch set to the “18 or More” position. As the input is increased from a low value, say -80 dbv (-80 dbv means 80 db bel

36、ow 1 volt or .1 millivolt), the output will increase as much as the input until point A, the “threshold,” (the input level at which compression takes place), is reached. Above this input level (-56 dbv), the output will remain nearly constant over an input range of 40 db or more, as represented by c

37、urve A-A (on Figure 1a). The input threshold voltage, and consequently the regulated output level, may be increased by either 6 or 12 db by changing the setting of the DISTANCE SELECTOR. In this case, operation above the input threshold is represented by curves B-B” or C-C, ac- cording to the settin

38、g. These threshold voltages have been chosen to approximate the output of a typical microphone with an average speaker at the distances labeled on the switch. At greater distances or quieter speech, the output will follow the input, but if the person speaking is louder or closer to the microphone, t

39、he Audio Level Controller will prevent its output from increasing, thus eliminating “blasting” or overloading of subsequent electronics. INPUT LEVEL CONTROL: The INPUT LEVEL CONTROL is employed when a higher-than-normal signal level is fed into the M62V, such as the output of preamplifiers, line amp

40、lifiers, tape recorders or tuners. The INPUT LEVEL CONTROL may also be used as a vernier control to allow fine adjustments of the input threshold that may occur between the 6 db steps of the preset “DISTANCE SELECTOR” switch. High-impedance, unbalanced signals up to 10 volts can be applied to the hi

41、gh-impedance input; low- impedance, balanced signals no greater than 200 millivolts may be connected directly to the low-imped- ance input. If the low-impedance signal is greater than this (for example, a 600 ohm line at +4 dbm), a line adapter balanced attenuator such as the Shure A15LA may be conn

42、ected between the line and the input of the M62V. Alternately, if the line can be un- balanced (one side grounded), it may be connected to the high-impedance input with no attenuator. With such inputs, the DISTANCE SELECTOR should be set to the “6 or Less” position. To adjust the INPUT LEVEL CONTROL

43、, monitor the output of the M62V and apply an average level input. Starting at 0, ad- vance the INPUT LEVEL control. The signal will begin to appear at the output and will increase in volume until a point is reached at which no further increase is noted. This is the threshold, and if the control is

44、left at this setting, any inputs less than the test input level will pass through the M62V uncontrolled, while those which are louder will be prevented from rising and overloading succeeding equipment. Operation of the Audio Level Controller above the constant output region is not recommended. The c

45、urves shown on Figure la and b are valid when the INPUT LEVEL CONTROL is used; however, the appropriate attenua- tion must be added to the Input Voltage (Horizontal) Scale. For example, if the INPUT LEVEL CONTROL is set to “5” approximately 20 db should be added to RadioFans.CN 收音机爱 好者资料库 the input

46、voltage figures, so the point marked -60 dbv on the input voltage scale (Horizontal) would become -40 dbv. In other words, the entire curve would be shifted 20 db to the right. TO USE WITH SHURE M68 SERIES MICROPHONE MIXERS: The two ways of using the M62V with the M68 Series Mixers are: 1. Connect a

47、 microphone directly into the Hi or Lo impedance input of the M62V. Connect the microphone level output of the M62V (Hi or Lo impedance) to a microphone input on the M68 mixer (either Hi or Lo Impedance, whichever was selected on the M62V). This method gives audio “Level-Loc”control on the one micro

48、- phone attached to the M62V ONLY. All other inputs to the M68 are unaffected. 2. Connect the M62V to control ALL inputs of the M68 mixer, by connecting the microphone level output of the M68 to the input of the M62V, (if the Lo Imp. microphone level output of the M68 is used the M62V input must be

49、set on LOW Impedance, if the Hi Impedance microphone level output of the M68 is used, the M62 input must be set on Hi Impedance) or connect the Aux. Hi level output of the M68 to the input (set on Hi Imp.) of the M62V. (The INPUT LEVEL CON- TROL may be used to control the threshold level as covered under “INPUT LEVEL CONTROL.”) The input for the main amplifier or tape recorder is then connected to the M62V microphone level output (Hi or Lo Imp.) or the AUX. OUTPUT. When used in this manner, the MASTER CON- TROL of the M68 Mixer should be set to about “5” and the individual controls use