Shure VA302 Schematic

VA302 SERIES

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OPERATING AND SERVICE MANUAL

Manufactured by

SHURE BROTHERS

Evanston, Illinois 60204 U.S.A.

AL406

(RE)

27A818

INC.

222 Hartrey Avenue

Printed in

U.S.A.

VA302

VA302 Series Vocal Master

SPECIFICATIONS

Series Console Amplifier Type Power Output

Voltage Gain

Frequency Response Input Impedance

Distortion Hum and Noise

Speaker Load lmpedance

Input Clipping Level

Bass Control Action ............................

Treble Control Action

"Aux. Hi-Level" Output Jack

...................................

...........

.....................................

.I00

watts continuous '(RMs); (to 8 ohm load, see Figure

.....................................

.........

...........................................

..................................................

Nominal

.............................

........................

............... .Impedance

output (to 8 ohm load); nominal

i10

.All silicon transistor mixer/power amplifier

Page

.80

db Input Attenuator "Out"

.5%

ohms; operational

.Greater than

Greater than

t13

db at

10,000

5,000

V at

watts to speakers, Clipping Level 4 V.

db lnput Attenuator "In" (8 ohm load)

Hz.

.320

ohms lnput Attenuator "Out"

500

ohms lnput Attenuator "In"

maximum at rated output at

.60

db below rated output

(See Figure

Mv. Input Attenuator "Out"

150

Mv. lnput Attenuator "In"

100

Hz.

with respect to "flat" setting

Hz.

with respect to "flat" setting

ohms; Output

ohm load)

20,000

5.3

Hz.

(typical)

ohms minimum

Page 7)

db below speaker

KHz.

"Mic. Level" Output ............. Hi-Z: impedance

Lo-Z: impedance

Echo-"To Input" Jack (Output To External Echo Unit)

Output

Echo-"To Output" Jack (Input From External Echo Unit)

"Reverb Switch" Jack

Center Notch Frequencies of "Anti-Feedback" Filters

db above microphone inputs with individual volumes at

200

Sensitivity

"Master Volume" Control at maximum settings; Clipping Level

setting of "Echo Gain" control. Clipping level increases with reduced

....................

Mv. for rated amplifier output with "Echo Gain" Control and

1,000

D.C. switching (no audio), parallels the Master Reverb

In-Out Switch. Any cable with a resistance of less

ohms; Output

..................

.................

nominal

ohms; Output

nominal

setting of "Echo Gain" control.

than

......

db below auxiliary output;

Mv. Clipping Level

db below auxiliary output;

Mv. Clipping Level

.Impedance

"10";

Clipping Level 3 V.

Impedance

V. with maximum

5,000

ohms may be used.

Filter "A"

Filter

"B"

Filter "C"

Filter "D"

120

10,000

ohms;

40,000

ohms;

5,000 2,200 1,000

155

Mv. Mv.

Hz.

Hz. Hz.

Hz.

Console (Continued) power Supply: VA302-C

VA302E-C VA302E6-C

Power Consumption

Ambient Temperature Range

Dimensions

Weight: VA302-C

VA300-S Speaker Column Power Rating Impedance Frequency Response Horizontal Distribution

.................................

........................................................

VA302E-C and VA302E6-C

.................................................................

.....................................................................

..................................................

...........................................

....................................

..................................................

..............................................................

.........................

.................

,100, 120,140, 200, 220, 240 volts, 50160 Hz.

180 watts with

-7°C. to 43°C. (20" F. to 11O0F.) without derating 213 mm height x 635 mm width x 375 mm depth

.........................................

,120 volts, 60 HZ.

Factory wired for 240 volt operation.

.80 watts maximum with no signal in.

KHz.

120/240 volts, 50160 HZ.

Switch selectable.

signal and 100 watts output,

400 watts maximum operating

(8% in.

in. x 14% in.)

18.6 kg (41 Ib) .19.05

50 Hz. to 10,000 Hz.

(42

Ib)

.I00 watts

16 ohms

140' Vertical Distribution Dimensions

Weight..

The Shure Model consists of one Control Console (VA302-C) and two Speaker Columns (VA300-S).

The Shure Model consists of one Control Console Speaker Columns (VA300-S).

Designed specifically for the performing vocalist, the Vocal Master Sound System provides the required portability, flexibility, and dependability demanded by professional entertainers.

mixerlpower amplifier Control Console permits the

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 Console. Unique circuitry design protects the solid-state components against damage as a possible result of open-circuit

...............................

.................................................

VA302 Vocal Master Sound System

VA302E Vocal Master Sound System

VA302E6 Vocal Master Sound System

.................................................................

(VA302E-C) and two

(VA302E6-C) and two

65'

1594 mm height x 400 mm width x 222

(62% in. x

31.78 kg (70 Ib) including cable

or short-circuit conditions of the amplifier outputs. The output transistors are also protected against overheating by the use of automatic thermal sensors. All components of the Vocal Master Sound System are conservatively rated and are operated well within their respective tolerances to assure long life and trouble-free performance.

The VA302-C is Underwriters' Laboratories, Inc. listed,

and is listed by the CSA Testing Laboratories as certified.

The VA300-S Speaker Columns are highly directional,

wide range, line-radiators. A rear-ported enclosure is uti-

lized which contributes to the directional characteristics of

the Speaker Column and is crucial in reduction of feed-

back.

VA300-S employs four special 8-inch loudspeakers

The and two special 10-inch loudspeakers providing a total cone area of 2,310 cm2 (358 in2).

Each Speaker Column is furnished with a

gauge, 2-conductor rubber jacketed cable with locking

phone plugs attached.

15% in.

mm depth

in.)

15m (50 ft), #I8

FIGURE

Front Panel Controls (Refer to Figure 1)

1. "Anti Feedback" Switches (Four).

"Reverb Intensity" Control.

3. "Reverb Treble

"Master Reverb" Switch. 10. V.U. Meter "Hi/Lo" Sensitivity Switch.

Individual Channel "Volume" Controls (Six). 11. V.U. Meter.

Bass" Controls (Dual Concentric).

Individual Channel "Treble & Bass" Controls (Six, Dual Concentric).

Individual Channel "Reverb" Switches (Six).

"Master Volume" Control.

"On-Off-On" Power Switch.

Rear Panel Controls and Connections (Refer to Figure 2)

11. Line Cord Storage Spindles.

12. A.C. Line Cord.

13. D.C. Fuse

(3AG/5A).

14. A.C. Fuse (3AG/3A/SB).

15. "Thermal Overload" lndicator Lamp.

16. "Reverb Switch" Remote Control Jack (Phone Type).

17. "Speaker" Output Jacks (Two, Phone Type).

18. "Aux. Hi-Level" Output.

19. "Low-Hi" Impedance Switch for Microphone Output

FIGURE

20. "Microphone" Level Output Connector (Male Cannon Type).

21. Echo-"To Input" Jack (Switching Phone Type).

22. Echo-"To Output" Jack (Switching Phone Type).

23. Echo "Gain" Control. "ln/Out" lnput Attenuator Switches (Six).

24.

25. "lnput" Connectors (Six, Female Cannon Type).

26. "Voltage Selector" Switch.

27. "Thermal Overload" lndicator Lamp.

28. A.C. Fuse (1.6 AT or 3.0 AT).

29. A.C. Power (Mains) Connector.

30. D.C. Fuse (5.0 A).

General Operating Instructions:

1. Set all front panel controls in the following manner: All switches Intensity" Control and and (6), set in the "flat response" position (indicator ribs at the "Off" position; "Hi-Lo" Sensitivity Switch (10) in the "Hi" position.

2. Unwrap the A.C. line cord (12) from the storage spindles (11); plug line cord into an outlet. The VA302-C is designed to operate from outlets supplying 110 to 130 volts, 60 Hz. The operate from outlets supplying 220 to 260 volts, 50 to 60 operate on 110 to 130 volts, 50 to 60 Hz. See page 8 for instructions. The VA302E6-C is designed to operate from outlets supplying 100, 120, 140, 200, 220, or 240 volts, 50 to 60 Hz. as selected by an integral voltage-selector switch. See page 8 for instructions.

3. Remove the speaker cables from the storage compartments in the 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" (17). These plugs are provided 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, each Speaker Column has a pair of parallel-wired input jacks, an alternate speaker hook-up would be to connect a speaker cable from the Console to one Speaker Column and then connect a second cable from this Speaker Either hook-up will provide an 8 ohm load. If longer speaker cables are required, see page 6.

4. Connect one or more low impedance microphones to the Console at the connectors marked "Inputs" (25). The Console is designed to operate with any high quality dynamic or ribbon-type low impedance microphone. For high impedance microphones see page 11.

5. Set all six Input Attenuator Switches (24) on the rear panel of the Console to "Out." These switches should generally be set in the "Out" position when using low impedance dynamic or ribbon microphones. See page 6 for a description of the switch function.

6. Turn on the Power Switch (9) located on the front panel of the Console. Set the "Master Volume" Control (8) to

"5." While talking or singing into one of the microphones connected to the console, turn up the indi-

vidual volume control for that microphone to a normal

level. On Consoles with a three-position Power Switch (9), use the "On" position which results in the least

amount of hum coming from the speakers.

(I), (4), (7), set to "Out" position; "Reverb

(2), and all "Volume" Controls (5)

(8), set at "0"; all "Treble" and "Bass" Controls (3)

12:OO o'clock); "On-Off-On" Switch (9) set in

VA302E-C is wired at the factory to

Hz.

simple wiring change allows the VA302E-C to

VA3OO-S Speaker Columns. Insert and

#18 gauge unshielded cable. Since

Column to the second Speaker Column.

7. Now turn up the other lndividual Channel Volume Controls (5) which are being used. By use of the individual Channel Volume Controls balanced for level so that the sound coming from the speakers is in proper balance for each microphone. Increasing or decreasing the Volume on one channel will have no effect on the other channels of the Console.

8. Note the action of the Individual Treble and Bass Con-

9. Turn the Reverb Intensity Control

10. Set all four Anti Feedback switches (1) to the "Out"

11. The Master Volume Control (8) will raise or lower the

12. For most applications set the V.U. Meter Sensitivity

(61;

trols type, the large knob being the Bass control and the smaller knob being the Treble control. Each of these knobs incorporates an indicating rib. Under average conditions, the controls should be set with indicating ribs facing straight up vide a normal "flat" frequency response. All Treble and Bass Controls on the Console operate in the same manner; turning the controls clockwise respectively 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.

"4." Set the Master Reverb switch (4) to the "In" position. Reverberation may now be selectively added to any of the six channels by setting the Individual Channel Reverb switches

different settings of the Reverb Intensity Control (2)

will not affect the overall system gain. Generally a setting of

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 individual 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.

position. These switches can help eliminate feedback.

Each switch cuts out part of the critical generating frequencies. See page 8 for a detailed description on how to effectively use them.

volume of all channels simultaneously without affect-

ing 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.

Switch (10) to the "Hi" position. With an 8-ohm speaker

load (two watts output. With the Sensitivity Switch set to the

"Lo" position, a reading of put. Adjust the volume controls for the desired sound

level. Note the meter reading and use it as a visual

reference for the desired sound level. For further information on the V.U. Meter, see page 9.

these controls are of the dual concentric

"1" to

"4"

of the Reverb lntensity Control

VA3OO-S), a reading of 0 db indicates 50

(5), the microphones may be

(12:OO o'clock position) to pro-

(2)

to a setting of

(7)

to the "In" position. Note that

feedback-

0 db indicates 2 watts out-

(2)

lnput Connections:

Six individugl input connectors are provided on the rear

panel of the Console. These connectors are professional 3-pin female audio connectors (25). The Console is designed to operate with any high quality dynamic or type low impedance microphone.

The main advantage of low impedance microphones

is that virtually unlimited cable lengths may be used, whereas high impedance microphones require that cable length not exceed 6m (20 ft).

Low impedance microphones should be wired using low capacitance, two-conductor, shielded cable (such as den #8412, #8422). When wiring professional 3-pin audio connectors, the cable shield should be connected to Pin

and one of the two conductors to Pin No. 2, the other

No. conductor. to Pin No. 3. When using several microphones, consistency of cable wiring should be followed to insure that all microphones are "in phase."

To test two microphones and their cables for proper phasing, connect them to the Console. Talk or sing into the two microphones while holding them three or four inches apart. The amplified sound from the speaker column will be the same when talking directly into either microphone or directly between them if they are in phase with each other. If the sound drops drastically, or a dead spot is found when talking between the two microphones, one of them, or their cables, is out of phase.

To change the phase of the one microphone, or cable, interchange the conductors that are wired to Pins No. 2 and No. 3 of the 3-pin connector. Test all the microphones

and cables this way to insure that they are all "in phase"

with each other.

For high impedance microphones, see page 11.

For additional microphone inputs, connections from electrified musical instruments, and connections to play back a tape, see page 11.

ribbon-

Bel-

lnput Attenuator Switches:

Six individual input attenuator switches (24) are located above the six input connectors. These screwdriver-slot slide switches allow the microphone input signal to be attenuated (reduced) before entering the preamplifier.

With the switch in the "Out" position, the signal from the microphone is switched directly to the preamplifier of

the channel. With the switch in the

nal from the microphone is attenuated by 15 db before en-

tering the preamplifier.

This feature may be useful when working the microphones very close to the performer's lips as with "hard rock" vocalists, who may produce signals in excess of

the clipping level of the preamplifiers; in such an instance, the attenuator will generally eliminate the distortion which would otherwise occur.

"In" position, the sig-

Output Connections:

Two parallel-wired "Speaker" output connectors are

provided on the rear panel of the Console. These connec-

tors are standard phone jacks (17).

Full rated output of the 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 (overheating) may result.

It should be 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:

jacks or the speaker cables between two Vocal Master Amplifiers or the Vocal Master and any other amplifier. This may result in damage to one or both amplifiers, and is not covered by the Guarantee.

The Vocal Master does not use speaker output matching transformers and thus avoids the distortion, power loss and added weight inherent in such transformers. The

speaker output voltage is 28.3 volts, to 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 connect from the Console to each 16-ohm

speaker. Greater cable lengths require heavier gauge wire to avoid appreciable power loss in the speaker cable. For

30 to 51 m (100 to 170 ft), use

270 ft), use

#12 gauge wire. To maximize the power to each speaker, a

separate cable should be used to connect each speaker to the Console.

Do not interconnect the speaker output

#8452,8478,8460, or 8461) may be used to

(VA3OO-S)

#16 gauge; 51 to 81 m (1 70 to

#f4 gauge; and 81 to 128m (270 to 425 ft), use

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 sound 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 utilizes two special 10-inch speakers and four special 8inch speakers, and has a total speaker cone area of 2,310 cm2 (358 in2) per column. The VA300-S Speaker Column delivers virtually uniform penetrating power over a in the horizontal plane and a 65" angle in the vertical plane.

The rear-ported enclosure of the VA300-S contributes to

its highly directional pattern, which is critical in achieving maximum audience penetration and reduction of feedback.

The Shure VA3Ol-S Speaker Column is intended primarily for use as an "on-stage monitor." While this speaker meets all of the criteria for an excellent vocal system

speaker, its area of coverage is more localized than that

VA3OO-S. The nominal impedance of the VA3Ol-S is

of the

32 ohms, so that when used in conjunction with two

VA3OO-S Speaker Columns, the total system impedance becomes 6.4 ohms. An integral volume control on the VA301-S permits its use on-stage as a monitor at the highest possible sound level without feedback.

COIU~~

140" angle

The following list shows various speaker combinations and the resultant impedance loads which are suitable for use with the Vocal Master Console:

QUANTITY and IMPEDANCE

SPEAKER MODEL OHMS (NOMINAL)

~~301

VA300-S and 1 VA301-S

1 VA300-S and 2 VA301-S 1 VA3OO-S and 3 VA301 1 VA300-S and 4 VA301 -S 2

VA3OO-S and 1 VA301-S

VA3OO-S and 2 VA301-S

-S

VA301 -S

-S

If additional speakers (more than in the table above) are required, use a Shure Power Master Amplifier to drive the extra speakers. See page 12 for instructions.

FIGURE

5678910

IMPEDANCE

Typical output power vs. speaker load impedance for

the Vocal Master Console.

(OHMS)

Column Speaker Placement:

It must always be kept in mind that every room or space is acoustically unique and there are no set "rules" for speaker placement. A number of generalizations however may be made which will at least provide a good starting point under various conditions.

Always consider speaker placement in relation to microphone placement. It is desirable for the loudspeakers and microphones to be in close proximity in order to provide

the illusion of source-oriented sound. Source-oriented sound, ideally, should provide the listener with the illusion that all of the sound is coming directly from the sound source, the stage or performance area. It is also desirable to keep loudspeakers and microphones separated in order to achieve a high threshold of acoustic feedback. While these statements are contradictory, a good solution to both can generally be accomplished.

When the VA300-S Speaker Columns are used on stage, as they most often are with a portable system, the speakers should be placed at the sides of the stage and as far forward as possible. With this setup, the entire stage area will be relatively free from acoustic feedback; also the illusion of sound coming from the center of the stage will be quite good except for the first few forward rows of seats.

The Shure VA300-S Speaker Column has been designed with rear ports to give the column a bidirectional horizontal polar pattern below 200 Hz. This design feature was decided upon in order to reduce low frequency acoustic feedback and provide a relatively "dead" area at the sides of the column with the result that microphones may be placed

there with minimal feedback problems at low frequencies.

Try to keep the speaker columns above the heads of the audience. The easiest way to do this is put the speaker columns on the stage. If the stage is only a foot or two high, raise the speaker columns up by placing them on a

solid platform or box.

Keeping in mind that the speaker columns have a narrow coverage angle in the vertical plane and a broad coverage

angle in the horizontal plane, here are a few generalizations on speaker requirements for various room shapes.

A deep, narrow auditorium would generally require only

two speakers if the seating is all on one level. If balconies were added to this same room, additional speaker columns would be required to aim sound up into them.

A shallow, broad room might require four speakers to

be utilized in order to cover the extreme horizontal ex-

panse. Again if balconies were added, four more speakers might be required to expand the vertical coverage.

The "Theatre-in-the-Round" will almost always necessitate the use of at least four columns. More speakers might be required to provide adequate horizontal coverage if the theatre is very deep.

To "aim" speakers up for effective coverage of a balcony, use the Shure Model

A3S-S stand will provide added stability and approxi-

The

mately

of up to

15O of tilt. The A3S-T stand provides adjustable tilt

30'. In an emergency, a spare microphone stand

A3S-S or A3S-T Speaker Stand.

can be used to hold up a tilted speaker column. Adjust the height of the microphone stand to one or two inches less

than the height of the top edge of the upper rear port on the back of the speaker. Tilt the speaker back until the top edge of the upper rear port rests on the top of the microphone stand. Changing the height of the microphone stand adjusts the amount of tilt on the speaker.

The VA300-S Speaker Column may be used on its side,

though this reduces the horizontal coverage and the pene-

trating power. In a low ceiling, small intimate room such

as a night club, horizontal mounting, at or near the ceiling level may be very successful. An alternate solution for this

type of small room is to use

VA3Ol-S Monitor Speakers. It is not recommended that the VA300-S Speaker Column be used on its side in larger rooms.

It is not possible to adequately cover all

phases of speaker placement in all types of rooms in this manual. Just remember that every room is acoustically different from any other and therefore speaker placement will vary from room to room.

Good speaker placement will provide the audience with even distribution of sound intensity, sound which is free from excessive reverberation and echoes, and the illusion of sound emanating from the real source.

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