shure_va300_vocal-master_sm 电路图.pdf

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1、VA 300 OPERATING AND SERVICE MANUAL Manufactured by SHURE BROTHERS INC. 222 Hartrey Avenue Evanston, Illinois 60204 U. S. A. Copyright 1978, Shure Brothers Inc. AL404 (RE) 27A819 Printed in U. S. A. RadioFans.CN 收音机爱 好者资料库 VA300 SPECIFICATIONS VA300-C Console Amplifier Type . . . . . . . . . . . . .

2、 . . . . . . . . . . . . . . .All silicon transistor mixer/power amplifier Power Output. . . . . . . . . . . 100 watts continuous (RMS); (to 8 ohm load, see Figure 3, Page 7) Voltage Gain. . . . . . . . . . . . . . . . . . . . . . . . . . .60 db “Mic.” Input Level (8 ohm load) 49 db “Inst.” Input Le

3、vel (8 ohm load) Frequency Response . . . . . . . . . . . . . . . . . . . . . . . . . . 2 db 40 Hz. to 20,000 Hz. (typical) Input Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60,000 ohms “Mic.” Input Level 120,000 ohms “Inst.” Input Level Distortion . . . . . .

4、. . . . . . . . . . . . . . . . . . . . . . . . . .5% maximum at rated output at 1 KHz. Hum and Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 db below rated output Speaker Load Impedance . . . . . . . . . . . . . . . .Nominal 8 ohms; operational 5.3 ohms mi

5、nimum (See Figure 3, Page 7) Input Clipping Level . . . . . . . . . . . . . . . . . . . . . . . Greater than 300 Mv. (“Mic.” Input Level) Greater than 1 V. (“Inst.” Input Level) Bass Control Action . . . . . . . . . . . . . . . . . . . . . 13 db at 100 Hz. with respect to “flat” setting Treble Contr

6、ol Action . . . . . . . . . . . . . . . . . . 10 db at 10,000 Hz. with respect to “flat” setting “To Tape Recorder” Jack . . . . .Impedance 5,000 ohms; Output 19 db below speaker output; nominal - 2 V at 50 watts to speakers, Clipping Level 4 V. Echo-“To Input” Jack (Output To External Echo Unit) .

7、. . . . . . . . . . .Impedance 10,000 ohms; Output 20 db above microphone inputs with individual volumes at “10”; Clipping level 3 V. Echo-“To Output” Jack (Input From External Echo Unit) . . . . . . . . . .Impedance 40,000 ohms; Sensitivity 200 Mv. for rated amplifier output with “Echo Gain” Contro

8、l and “Master Volume” Control at maximum settings; Clipping level 2 V. with maximum setting of “Echo Gain” control. Clipping level increases with reduced setting of “Echo Gain” control. “Reverb Switch“ Jack . . . . . . . . . . . . . . . . D.C. switching (no audio), parallels the Master Reverb In-Out

9、 Switch. Any cable with a resistance of less then 5,000 ohms may be used. Center Notch Frequencies of “Anti-Feedback” Filters. . . . . . . . . . . . . .5,000 Hz. 2,200 Hz. 1,000 Hz. 155 Hz. 2 RadioFans.CN 收音机爱 好者资料库 VA300-C Console (contd) Power Supply . . . . . . . . . . . . . . . . . . . . . . . .

10、 . . . . . . . . .120 volts, 60 Hz. 80 watts maximum with no signal in. 180 watts with 1 KHz. signal and 100 watts output 400 watts maximum operating -7C to 43C (20F to 110F) without derating Power Consumption . . . . . . . . . . . . . . . . . . . Ambient Temperature Range. . . . . . . . . Dimension

11、s. . . . . . . . . . . . . . . . . . . . . . . .213 mm height x 635 mm width x 375 mm depth (8-3/8 in. x 25 in. x 14-3/4 in.) Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17.25 kg (38 Ibs.) VA300-S Speaker Column Power Rating . . . . . . . . . . . . . .

12、 . . . . . . . . . . . . . . . . . . . . . . 100 watts Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 ohms Frequency Response. Horizontal Distribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Hz. to 10,000 Hz. 140 Vertical Distribution.

13、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 5 Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . 1594 mm height x 400 mm width x 222 mm depth (62-3/4 in. x 15-3/4 in. x 8-3/4 in.) Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14、 . . . . . . 31.78 kg (70 Ibs.) including cable DESCRIPTION The Shure Model VA300 Vocal Master Sound System con- sists of one Control Console (VA300-C) and two Speaker Designed specifically for the performing vocalist, the Columns (VA300-S). VA300 Vocal Master Sound System provides the required port

15、ability, flexibility, and dependability demanded by profes- sional entertainers. The VA300-C mixer/power amplifier Console permits the user to mix up to six microphones with individual control over volume, tone and reverberation. A solid-state 100 watt R.M.S. power amplifier is incorporated in the C

16、onsole. Unique cir- cuitry design protects the solid-state components against dam- age as a possible result of open-circuit or short-circuit condi- tions of the amplifier outputs. The output transistors are also protected against overheating by the use of automatic thermal sensors. All components of

17、 the VA300 Vocal Master Sound System are conservatively rated and are operated well within their respective tolerances to assure long life and trouble-free The VA300-C is Underwriters Laboratories, Inc. listed, and is listed by the CSA Testing laboratories as certified. performance. The VA300-S Spea

18、ker Columns are highly directional, wide range, line-radiators. A rear-ported enclosure is utilized which contributes to the directional characteristics of the Speaker Column and is crucial in reduction of feedback. The VA300-S employs four special 8-inch loudspeakers and two special 10-inch loudspe

19、akers providing a total cone area of 2,310 cm (358 in). Each Speaker Column is furnished with a 15m (50 ft) #18 gauge, 2-conductor rubber jacketed cable with locking phone plugs attached. 3 RadioFans.CN 收音机爱 好者资料库 Figure 1 Front Panel Controls (Refer to Figure 1)6. Individual Channel “Treble “Reverb

20、 Intensity” Control (2). and all “Volume” Controls (5) and (8), set at “0”; all “Treble” and “Bass” Controls (3) and (6). set in the “flat response” position (indicator ribs at 12:00 oclock); “On-Off-On” Switch (10) set in the “Off” position. 2. Unwrap the A.C. Line cord (12) from the storage spindl

21、es (11); plug line cord into a 110 to 130 volt, 60 Hz. outlet. The line cord is a 2.75m (9 ft), 3-conductor cord with a 3-pin grounding plug. If extension cords are required, use a high quality, rubber-jacketed cable with #18 gauge wire or larger. 3.Remove the speaker cables from the storage compart

22、- ments in the VA300-S Speaker Columns. Insert and lock the right angle phone plug on the cable into either of the two parallel-wired phone jacks; one on each Speaker Column. Connect the other end of each cable to the jacks on the rear panel of the Console marked “Speakers” (15). These plugs are pro

23、vided with locking rings to lock the plug to the jack. Each speaker cable is 15m (50 ft) in length and is made from heavy duty 2-conductor, #18 gauge unshielded cable. Since each Speaker Column has a pair of parallel-wired input jacks, an alternate speaker hook-up would be to connect a speaker cable

24、 from the Console to one Speaker Column and then connect a second cable from this Speaker Column to the second Speaker Column. Either hook-up will provide an 8 ohm load. If longer speaker cables are required, see page 6. 4. Connect one or more high impedance microphones to the Console at the connect

25、ors marked “Inputs” (22). The VA300 is designed to operate with any high quality dynamic orribbon-type high impedance microphone. For low impedance microphones see page 1 0 . 5.Set all six Input Attenuator Switches (21) on the rear panel of the Console to “Mic.” These switches should generally be se

26、t in the “Mic.” position when using high impedance dynamic or ribbon microphones. See page 6 for a description of the switch function. 6. Turn on the Power Switch (10) located on the front panel of the Console. Set the “Master Volume” Control (8) to “5.” While talking or singing into one of the micr

27、ophones connected to the console, turn up the individual volume control for that microphone to a normal level. If at this point a slight hum is heard in the speakers, switch the Power Switch (IO) to whichever 7. 8. 9. 10. 11. “On” position results in the least amount of hum coming from the speakers.

28、 Now turn up the other Individual Channel Volume Controls (5) which are being used. By use of the Indivi- dual Channel Volume Controls (5), the microphones may be balanced for level so that the sound coming from the speakers is in proper balance for each micro- phone. Increasing or decreasing the Vo

29、lume on one channel will have no effect on the other channels of the Console. Note the action of the Individual Treble and Bass Con- trols (6); these controls are of the dual concentric type, the large knob being the Bass control and the smaller knob being the Treble control. Each of these knobs inc

30、orporates an indicating rib. Under average condi- tions, the controls should be set with indicating ribs facing straight up (12:00 oclock position) to provide a normal “flat” frequency response. All Treble and Bass Controls on the Console operate in the same manner; turning the controls clockwise re

31、spectively increases Bass or Treble, counterclockwise decreases Bass or Treble. Note that changing the Bass or Treble Controls on one channel has no effect on the other channels of the unit. Turn the Reverb Intensity control (2) to a setting of “4” Set the Master Reverb switch (4) to the “In” positi

32、on. Reverberation may now be selectively added to any of the six channels by setting the Individual Channel Reverb switches (7) to the “In” position. Note that different settings of the Reverb Intensity Control (2) will not effect the overall system gain. Generally a setting of “1” to “4” of the Rev

33、erb Intensity Control (2) is adequate for vocals. The Reverb Treble and Bass Controls (3) operate in the same manner as those of the individual channel Treble and Bass Controls but provide independent tonal balance of the reverberant signal only. These controls do not affect the tone of the individu

34、al channels. For example, increasing Treble and decreasing Bass will approximate the reverb sound of a tape-type reverberation unit while decreasing Treble and increasing Bass will approximate the sound of a plate-type reverberation device. Set all four Antifeedback switches (1) to the “Out” positio

35、n. These switches can help eliminate feedback. Each switch cuts out part of the critical feedback-generating frequencies. See page 8 for a detailed description on how to effectively use them, The Master Volume Control (8) will raise or lower the volume of all channels simultaneously without affectin

36、g the “balance,” or “mix.” NOTE: With the Console driven at or near full power, pilot lamps will dim or vary in brightness; this is a normal condition. 5 Input Connections: Six individual input connectors are provided on the rear panel of the Console. These connectors are standard 1/4 inch phone jac

37、ks (22). The Console is designed to operate with any high quality dynamic or ribbon-type high impedance micro- phone. High impedance microphone cables should be limited to a maximum length of 6m (20 ft) to avoid high frequency signal loss and to reduce the possibility of hum and noise pickup in the

38、cables. Standard 1/4 inch phone plugs should be attached to the “Console end” of the microphone cables; the center conductor of the cable should be attached to the “tip” terminal of the phone plug and the shield of the cable should be connected to the “sleeve” terminal. For low impedance microphones

39、, see page 10. For additional microphone inputs, see page 10. For connec- tions from electrified musical instruments, see page 10. For connections to play back a tape, see page 9. For connections to a phonograph, see page 10. Six individual input level adjustment switches (21) are lo- cated above th

40、e six input jacks. These screwdriver-slot slide switches allow the microphone input signal to be attenuated (reduced) before entering the preamplifier. With the switch in the “Mic.” position, the signal from the microphone is switched directly to the preamplifier of the channel. With the switch in t

41、he “Inst.” position, the signal from the microphone is attenuated by 11 db before entering the preamplifier. This feature may be useful when working the microphones very close to the performers lips as with “hard rock” vocalists, who may produce signals in excess of the clipping level of the preampl

42、ifiers; in such an instance, the attenuator will generally eliminate the distortion which would otherwise occur. Output Connections: Two parallel-wired “Speaker” output connectors are pro- vided on the rear panel of the VA300. These connectors are standard phone jacks (15). Full rated output of the

43、amplifier is obtained when the speaker load is 8 ohms (two VA300-S Speakers). Speaker loads of less than 5.3 ohms (more than three VA300-S Speakers) should not be used with this amplifier. No damage to the speakers or amplifier will occur, but thermal shutoff of the amplifier may result. It should b

44、e noted that various speaker loads will affect the output power of the amplifier. See Figure 3, Page 7 to determine amplifier output power for the given speaker load. WARNING: Do not interconnect the speaker output jacks or the speaker cables between two VA300 Amplifiers or the VA300 and any other a

45、mplifier. This may result in damage to one or both amplifiers, and is not covered by the Guarantee. The VA300 does not use speaker output matching trans- formers and thus avoids the distortion, power loss and added weight inherent in such transformers. The speaker output vol- tage is 28.3 volts, to

46、an 8-ohm load, for 100 watts. This allows long speaker lines with wiring practices consistent with those used for 25-volt speaker lines. Up to 30m (100 ft) of #18 gauge two-conductor cable (such as Belden #8452, 8478, 8460, or 8461) may be used to connect from the VA300-C to each 16-ohm (VA300-S) sp

47、eaker. Greater cable lengths require heavier gauge wire to avoid appreciable power loss in the speaker cable. For 30 to 51m (100 to 170 ft), use #16 gauge; 51 to 81m (170 to 270 ft), use #14 gauge; and 81 to 128m (270 to 425 ft), use #12 gauge wire. To maximize the power to each speaker, a separate

48、cable should be used to connect each speaker to the VA300. Speakers: Selection of speakers for use in a vocal music system is most critical. The factors which most significantly contribute to an outstanding vocal speaker system are correct frequency range, distortion-free reproduction, and enough so

49、und power to fully penetrate the audience area. The Shure VA300-S Speaker Column has been designed to provide all of these features. It is recommended that VA300-S Speaker Columns be used in pairs, each column having a nominal impedance of 16 ohms, which provides an impedance of 8 ohms when two are used. Each column utilizes two special IO-inch speakers and four special 8-inch speakers, and has a total speaker cone area of 2,310cm (358 in) per column. The VA300-S Speaker Column delivers virtually uniform penetrating power over a 140 angle in the horizontal plane and