Shure VA 300 User Manual

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
VA300 SPECIFICATIONS
VA300-C Console
Amplifier Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . All silicon transistor mixer/power amplifier
Power Output . . . . . . . . . . .
Voltage Gain . . . . . . . . . . . . . . . . . . . . . . . . . . .
Frequency Response . . . . . . . . . . . . . . . . . . . . . . . . . . ± 2 db 40 Hz. to 20,000 Hz. (typical)
Input Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60,000 ohms “Mic.” Input Level
Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5% maximum at rated output at 1 KHz.
Hum and Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 db below rated output
Speaker Load Impedance . . . . . . . . . . . . . . . .
Input Clipping Level . . . . . . . . . . . . . . . . . . . . . . . Greater than 300 Mv. (“Mic.” Input Level)
Bass Control Action . . . . . . . . . . . . . . . . . . . . .
Treble Control 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;
100 watts continuous (RMS); (to 8 ohm load, see Figure 3, Page 7)
60 db “Mic.” Input Level (8 ohm load)
49 db “Inst.” Input Level (8 ohm load)
120,000 ohms “Inst.” Input Level
Nominal 8 ohms; operational 5.3 ohms minimum
(See Figure 3, Page 7)
Greater than 1 V. (“Inst.” Input Level)
± 13 db at 100 Hz. with respect to “flat” setting
nominal - 2 V at 50 watts to speakers, Clipping Level 4 V.
Echo-“To Input” Jack (Output To External Echo Unit) . . . . . . . . . . . .
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” Control and
“Master Volume” Control at maximum settings; Clipping level 2 V. with maximum
setting of “Echo Gain” control. Clipping level increases with reduced setting
“Reverb Switch“ Jack . . . . . . . . . . . . . . . .
In-Out Switch. Any cable with a resistance of less then 5,000 ohms may be used.
Center Notch Frequencies of “Anti-Feedback” Filters. . . . . . . . . . . . . .
D.C. switching (no audio), parallels the Master Reverb
Impedance 10,000 ohms;
of “Echo Gain” control.
5,000 Hz. 2,200 Hz.
1,000 Hz.
155 Hz.
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VA300-C Console (cont’d)
Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Consumption . . . . . . . . . . . . . . . . . . .
180 watts with 1 KHz. signal and 100 watts output
Ambient Temperature Range
Dimensions
Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . 213 mm height x 635 mm width x 375 mm
. . . . . . . . .
-7°C to 43°C (20°F to 110°F) without derating
80 watts maximum with no signal in.
400 watts maximum operating
depth (8-3/8 in. x 25 in. x 14-3/4 in.)
120 volts, 60 Hz.
17.25 kg (38 Ibs.)
VA300-S Speaker Column
Power Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 watts
Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 ohms
Frequency Response
Horizontal Distribution
Vertical Distribution
........................
................................
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
50 Hz. to 10,000 Hz.
140°
65°
Dimensions
Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . .
DESCRIPTION
The Shure Model VA300 Vocal Master Sound System con­sists of one Control Console (VA300-C) and two Speaker Columns (VA300-S).
Designed specifically for the performing vocalist, the VA300 Vocal Master Sound System provides the required portability, flexibility, and dependability demanded by profes­sional 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 Console. Unique cir­cuitry design protects the solid-state components against dam­age as a possible result of open-circuit 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 VA300 Vocal Master Sound
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.)
31.78 kg (70 Ibs.) including cable
System are conservatively rated and are operated well within their respective tolerances to assure long life and trouble-free performance.
The VA300-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 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 loudspeakers providing a total cone area of 2,310 cm² (358 in²).
Each Speaker Column is furnished with a 15m (50 ft) #18 gauge, 2-conductor rubber jacketed cable with locking phone plugs attached.
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Figure 1
Front Panel Controls (Refer to Figure 1)
1. “Anti-Feedback” Switches (Four).
2. “Reverb Intensity” Control.
3. “Reverb Treble & Bass” Controls (Dual Concentric).
4. “Master Reverb” Switch.
5. Individual Channel “Volume” Controls (Six).
6. Individual Channel “Treble & Bass” Controls (Six, Dual Concentric).
7. Individual Channel “Reverb” Switches (Six).
8. “Master Volume” Control.
9. “Thermal Overload” Indicator Lamp.
10. “On-Off-On” Power Switch.
Rear Panel Controls and Connections
11. Line Cord Storage Spindles.
12. A. C. Line Cord.
13. D. C. Fuse (3AG/5A).
14. A. C. Fuse (3AG/3ASB).
15. “Speaker” Output Jacks (Two, Phone Type).
16. “To Tape Recorder” Jack (Phone Type).
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Figure 2
(Refer to Figure 2)
17. “Reverb Switch” Remote Control Jack (Phone Type).
18. Echo-“To Input” Jack (Switching Phone Type).
19. Echo-“To Output” Jack (Switching Phone Type).
20. Echo “Gain” Control.
21. “Mic./lnst.” Input Attenuator Switches (Six).
22. “Input” Jacks (Six, Phone Type).
VA300 Vocal Master
OPERATING INSTRUCTIONS
General Operating Instructions:
1. Set all front panel controls in the following manner: All switches (1), (4). (7). set to “Out” position; “Reverb
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 o’clock); “On-Off-On” Switch (10) set in the “Off” position.
2. Unwrap the A.C. Line cord (12) from the storage
spindles (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 compart­ments 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 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, #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 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 connectors marked “Inputs” (22). The VA300 is designed to operate with any high quality dynamic or microphone. For low impedance microphones see page
10.
5. Set all six Input Attenuator Switches (21) on the rear panel of the Console to “Mic.” These switches should generally be set 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
microphones 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
ribbon-type high impedance
“On” position results in the least amount of hum
coming from the speakers.
Now turn up the other Individual Channel Volume
7. Controls (5) which are being used. By use of the Indivi­dual 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 micro­phone. Increasing or decreasing the Volume on one channel will have no effect on the other channels of the Console. Note the action of the Individual Treble and Bass Con-
8. 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 incorporates an indicating rib. Under average condi­tions, the controls should be set with indicating ribs facing straight up (12:00 o’clock 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 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. Turn the Reverb Intensity control (2) to a setting of
9.
“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 (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 Reverb 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
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. Set all four Antifeedback switches (1) to the “Out”
10. position. 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
11. volume of all channels simultaneously without affecting 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.
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Input Connections:
Six individual input connectors are provided on the rear panel of the Console. These connectors are standard 1/4 inch phone jacks (22). The Console is designed to operate with any high quality dynamic or ribbon-type high impedance micro­phone. 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 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, see page 10.
For additional microphone inputs, see page 10. For connec­tions 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 lo­cated above the 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 the “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 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.
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 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 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: Do not interconnect the speaker output jacks
or the speaker cables between two VA300 Amplifiers or the VA300 and any other amplifier. 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 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 #8452, 8478, 8460, or 8461) may be used to
connect from the VA300-C to each 16-ohm (VA300-S) speaker. 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 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 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 column utilizes two special IO-inch speakers and four special 8-inch speakers, and has a total speaker cone area of 2,310cm² (358 in²) per column. The VA300-S Speaker Column delivers virtually uniform penetrating power over a 140° angle 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, penetration and reduction of feedback.
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 of the VA300-S. The nominal impedance of the VA301-S is 32 ohms, so that when used in conjunction with two VA300-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.
the resultant impedance loads which are suitable for use with the VA300 Vocal Master:
required, use a Shure PM300 Power Master Amplifier to drive the extra speakers. See page 11 for instructions.
which is critical in achieving maximum audience
The Shure VA301-S Speaker Column is intended primarily
The following list shows various speaker combinations and
IMPEDANCE
QUANTITY and SPEAKER MODEL
1 VA300-S 2 VA300-S 3 VA300-S 1 VA301-S 2 VA301-S 3 VA301-S 4 VA301-S 5 VA301-S 6 VA301-S
1 VA300-S and 1 VA301-S 1 VA300-S and 2 VA301-S 1 VA300-S and 3 VA301-S 1 VA300-S and 4 VA301-S 2 VA300-S and 1 VA301-S 2 VA300-S and 2 VA301-S
OHMS (NOMINAL)
16
8
5.3
32
16
10.6 8
6.4
5.3
10.6 8
6.4
5.3
6.4
5.3
If additional speakers (more than in the table above) are
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Figure 3. Typical output power vs. speaker load impedance for the
VA300 Vocal Master
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 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 col-
umns 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.
relation to
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 expanse. 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 Speaker Stand. This stand will provide added stability and approximately 150 of tilt. In an emergency, a spare microphone 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 penetra­ting 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 VA301-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 ethos, and the illusion of sound emanating from the real source.
Power Connections:
Connect the line cord (12) to an outlet which supplies 120 volts AC, 60 Hz. power. The three-position toggle switch on the front panel of the VA300 controls power to the Console. This three-position switch (10) is used to reverse line polarity, for minimum hum.
If extension cords are required to supply power to the VA300, a high quality #18 gauge or larger cord should be used.
Do not connect more than one VA300, or other amplifier to one extension cord. Use separate extension cords for each amplifier. Use a maximum of two VA300’s or other amplifier
per 120 volt house circuit. Failure to adhere to the above will
result in loss of available output power and the risk of blowing
house fuses, but will in no way damage the VA300 amplifier.
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