-
Set all front panel controls in the following manner: All switches (I), (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:OO o'clock); "On-Off-On" Switch (9) set in the "Off" position; "Hi-Lo" Sensitivity Switch (10) in the "Hi" position.
-
Unwrap the A.C. line cord (12) from the storage spin- dles (11); plug line cord into an outlet. The VA302-C is designed to operate from outlets supplying 110 to 130 volts, 60 Hz. The VA302E-C is wired at the factory to operate from outlets supplying 220 to 260 volts, 50 to 60 Hz. A simple wiring change allows the VA302E-C to operate on 110 to 130 volts, 50 to 60 Hz. See page 8 for instructions. The VA302E6-C is designed to oper- ate from outlets supplying 100, 120, 140, 200, 220, or 240 volts, 50 to 60 Hz. as selected by an integral volt- age-selector switch. See page 8 for instructions.
-
Remove the speaker cables from the storage compart- ments in the VA3OO-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" (17). These plugs are provided with lock- ing 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 con- nect 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.
-
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 micro- phone. For high impedance microphones see page 11.
-
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.
-
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 micro- phones 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.
7.
8.
Now turn up the other lndividual Channel Volume Con- trols (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 Con- sole.
Note the action of the Individual Treble and Bass Con- trols (61; 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:OO o'clock position) to pro- 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.
Turn the Reverb Intensity Control (2) to a setting of "4." Set the Master Reverb switch (4) to the "In" posi- tion. Reverberation may now be selectively added to any of the six channels by setting the Individual Chan- nel Reverb switches (7) to the "In" position. Note that different settings of the Reverb Intensity Control (2) will not affect the overall system gain. Generally a set- ting of "1" to "4" of the Reverb lntensity Control (2) is adequate for vocals. The Reverb Treble and Bass Con- trols (3) operate in the same manner as those of the individual channel Treble and Bass Controls but pro- vide independent tonal balance of the reverberant sig- nal 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 decreas- ing Treble and increasing Bass will approximate the sound of a plate-type reverberation device.
Set all four Anti Feedback switches (1) to the "Out" position. These switches can help eliminate feedback. Each switch cuts out part of the critical feedback- generating frequencies. See page 8 for a detailed de- scription on how to effectively use them.
The Master Volume Control (8) will raise or lower the 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.
9.
10.
11.
12. For most applications set the V.U. Meter Sensitivity Switch(10)tothe"Hi" position.Withan8-ohmspeaker load (two VA3OO-S), a reading of 0 db indicates 50 watts output. With the Sensitivity Switch set to the "Lo" position, a reading of 0 db indicates 2 watts out- 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 in- formation on the V.U. Meter, see page 9.
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 de- signed to operate with any high quality dynamic or ribbon- 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 Bel- den #8412, #8422). When wiring professional 3-pin audio connectors, the cable shield should be connected to Pin No. 1 and one of the two conductors to Pin No. 2, the other 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 col- umn 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.
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 "In" position, the sig- nal from the microphone is attenuated by 15 db before en- tering the preamplifier.
This feature may be useful when working the micro- phones 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 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 dam- age 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: Do not interconnect the speaker output jacks or the speaker cables between two Vocal Master Amplifiers or the Vocal Master and any other ampli- fier. This may result in damage to one or both ampli- fiers, 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 prac- tices 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 Console to each 16-ohm (VA3OO-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 #f4 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 Console.
Speakers:
Selection of speakers for use in a vocal music system is most critical. The factors which most significantly con- tribute 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 C O I U ~ ~ utilizes two special 10-inch speakers and four special 8-
inch speakers, and has a total speaker cone area of 2,310 cm2(358 in2)per column. The VA300-S Speaker Column de-
livers 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, which is critical in achieving maximum audience penetration and reduction of feedback.
The Shure VA3Ol-S Speaker Column is intended primar- ily 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 VA3OO-S. The nominal impedance of the VA3Ol-S is 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.
The following list shows various speaker combinations and the resultant impedance loads which are suitable for use with the Vocal Master Console:
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 de- cided upon in order to reduce low frequency acoustic feed- back 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 generaliza- tions 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 necessi- tate 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 bal- cony, use the Shure Model A3S-S or A3S-T Speaker Stand. The A3S-S stand will provide added stability and approxi- mately 15O of tilt. The A3S-T stand provides adjustable tilt of up to 30'. 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 micro- phone 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.
QUANTITY and SPEAKER MODEL
5~ ~ 3-S0 1
6 VA301-S
1 VA300-S and 1 VA301-S 1 VA300-S and 2 VA301-S 1 VA3OO-S and 3 VA301-S 1 VA300-S and 4 VA301-S 2 VA3OO-S and 1 VA301-S 2 VA3OO-S and 2 VA301-S
IMPEDANCE OHMS (NOMINAL)
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.
LV
45678910 1520 3040 IMPEDANCE (OHMS)
FIGURE 3. Typical output power vs. speaker load impedance for the Vocal Master Console.
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 micro- phone 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.
VA302 Power Requirements:
The ~ ~ 3 0 2V-o6cal Master is furnished with a three con- ductor power cable and three-prong plug. Connect the power cable to an outlet which supplies 120 10% volts A.C., 60 Hz power. The three-position toggle switch on the front panel controls power to the amplifier. This switch (9) is also used to reverse line polarity for mini- mum hum. If extension cords are required to supply power to the VA302, a high quality #18 gauge or larger cord should be used.
VA302E Power Requirements:
The VA302E-C Vocal Master is furnished with a three- conductor power cable without a plug. To connect a plug to the power cable, attach the brown lead to the live ( f ) terminal of the plug, attach the blue lead to the neutral (-) terminal of the plug, and attach the green-yellow lead to the earth-ground terminal of the plug.
The VA302E-C is factory wired for operation from a nom- inal 240 volt power supply. Connect the power cable to an outlet which supplies 240 & 10% volts A.C., 50 to 60 Hz power. The three-position toggle switch on the front panel controls power to the amplifier. This switch (9) is also used to reverse line polarity for minimum hum. If extension cords are required to supply power to the VA302E, a high quality cable with conductors of 0.75 square millimeters cross- section or larger should be used.
An internal modification performed by competent per- sonnel will allow the VA302E to be used with 120 volt, 50 to 60 Hz power. To change the power supply wiring for 120 volt operation, do the following:
1. UNPLUG THE AMPLIFIER POWER (MAINS) CABLE.
2. Remove the amplifier from its carrying case as de- scribed on page 14.
3. With the amplifier upside-down, note the six wires from the power transformer TI.
4. Unsolder the yellow-black transformer lead wire and the red-black transformer lead wire from their solder- lug.
5. Resolder the yellow-black lead wire to the solder-lug to which the all-black transformer lead wire is already attached.
6. Resolder the red-black lead wire to the solder-lug to which the green-black transformer lead wire is al- ready attached.
7. Reinstall the amplifier in its carrying case.
8. Remove the four screws from the nameplate on the back of the amplifier. Turn the nameplate over and re- install. The nameplate nomenclature will now be suit- able for 120 volt use.
To change the VA302E back for use with 240 volt power, reverse the above steps. Be careful to reconnect the yellow-black and red-black transformer lead wires to an UNUSED-UNGROUNDED solder-lug. A pictorial diagram of the transformer lead wire connections is located on the inside of the chassis. The circuit diagram for both 120 volt and 240 volt operation is shown on page 22 of this manual.
VA302E6 Power Requirements:
The VA302E6-C Vocal Master is supplied with a detach- able three-conductor A.C. power (mains) cable without a connector on the "mains" end. To attach a connector, con-
nect the brown conductor of the cable to the "live" terminal of the connector, the blue conductor to the "neutral" ter- minal, and the green-yellow conductor to the "earth" (+) terminal.
The VA302E6-C is designed to operate from 100, 120, 140, 200, 220, or 240 volts, 50 to 60 Hertz power (mains). An integral voltage-selector switch, located on the rear panel, allows selection of the proper voltage.
As shipped from the factory, the VA302E6-C is set to op- erate from 240 volts.
The A.C. fuseholder, located nearest the voltage-selector switch, contains a 1.6 ampere slow-blow fuse (1.6 AT) which should be used when the unit is operated from 200 through 240 volts. When operated from 100 through 140 volts, this fuse should be changed to a 3 ampere slow- blow type (3.0 AT). The fuseholder located farthest from the voltage-selector switch contains a 5 ampere (5.0 A) fuse which should not be replaced by other values under any circumstances. Each of the three fuses mentioned is a 5mm x 20mm type, and two of each value are supplied with
the unit.
CAUTION - DO NOT CHANGE VOLTAGE-SELECTOR SWITCH SETTING OR ATTEMPT TO REPLACE FUSES WITHOUT FIRST DISCONNECTING THE A.C. POWER (MAINS) CABLE.
Thermal Overload/Ventilation:
The Console is equipped with thermal sensing switches on the heat-sinks of the output transistors. The thermal switches are set to shut off AC power to the amplifier when a temperature of 90°C. (194°F.) is attained on the heat- sinks; the switches will automatically recycle and return AC power when the heat-sink temperature reduces to 73°C. (164OF.). A thermal overload light (15), located on the rear panel, will indicate if thermal cycling has occurred. Thermal cycling may occur if air is not allowed to circulate through the grilles of the amplifier, if there is a prolonged short- circuit on the speaker output, or if the ambient temperature exceeds 43°C. (110°F.) while the console is operating at or near full power. Thermal cycling may also occur if the speaker load impedance is less than 5.3 ohms. See page 6, Output Connections, for instructions on speaker connec- tions.
Anti Feedback Switches:
Acoustic feedback (a howl or squeal in the speakers) may occur, depending on room acoustics and the physical placement of microphones in relation to the speakers, when volume is increased or when Bass or Treble controls are boosted. To minimize feedback, four Anti Feedback switches (1) are incorporated in the Console. These switches operate four "notch filters" which modify the fre- quency response of the unit. Each switch controls part of the audio spectrum. The top switch (A-yellow colored) fil- ters the highest feedback pitch (squeal), while the bottom switch (D-deep orange colored) filters the lowest feedback pitch (howl). The middle switches (B and C) filter the mid- dle feedback pitches. The action of each filter, with the exception of the (D) filter, has very little effect on the tonal quality of the voice. When using the (D) filter, a decrease in Bass tones may be noticed. To compensate for this simply increase all the individual Channel Bass controls slightly for the desired sound. This feedback switch (D) may be used in a very "boomy" environment to eliminate some of the low frequency room reverberation.
If feedback occurs, locate the one Anti Feedback switch (1) which eliminates the feedback. Gain may then be in- creased or tone control increased until another feedback pitch is apparent. One of the other filters may then be introduced which will eliminate that feedback. IMPOR- TANT: no more than two filters should be used simultane- ously; the effect of more than two filters is one of reduc- ing overall gain and the overall tonal quality of the system may be significantly affected.
Mixing:
Each of the six channels employ an individual Volume control, Bass control, Treble control, and reverberation selector switch.
Individual Volume controls permit proper mixing of the various inputs.
The Bass control allows 13 db of boost or attenuation at 100 Hz. It permits enhancement of a thin voice and is often useful as a low frequency attenuator in "boomy" rooms.
The Treble control permits 10 db of boost or attenuation at 10 KHz, and is useful to "brighten" an otherwise flat- sounding voice. It is often used to great advantage to re- duce high frequency acoustic reverberation in reflective rooms.
The Master Volume control (8) adjusts the output level of the total mixed output, allowing simultaneous increase or decrease of all channels without affecting the mix of the inputs.
Reverb:
The Vocal Master Console includes a built-in electro- mechanical spring-type reverberation device utilizing a total of four coil springs in two transmission paths. Re- verberation is accomplished by driving the input ends of the springs in a torsional mode and transferring the tor- sional movement at the other end of the springs back into an electrical signal which exhibits time delay with a long decay time. Since the reverberation device is an electro- mechanical device, it is sensitive to mechanical shock. It is recommended that if the console is moved while operat- ing, the Master Reverb In-Out switch (4) be set to the "Out" position. This will avoid the possibility of jarring the springs and producing unwanted sounds.
Unique to the Vocal Master is the fact that no matter how much reverberation is used, there is always a backbone of "dry" signal on the total output. Of great importance to the user, and also unique to the Vocal Master, is the system which permits the reverb intensity to be increased without increasing overall gain. In most units which employ artifi- cial reverberation, as the intensity of the reverberant signal is increased, the total gain also increases; this usually leads to acoustic feedback. The reverb mixing system used in the Vocal Master reduces the "dry" signal as the reverberant signal is increased; this accounts for an almost constant gain and reduces the possibility of feedback as reverb is added.
Three controls are pertinent to the Vocal Master Reverb operation. The amount of reverb is selected by the Reverb Intensity control (2). Generally, this control is not used above a setting of "5" for vocalists, though higher settings may be required for instruments. Separate Reverb Bass and Treble controls (3) are provided for the reverb signal only and are independent of the other tone controls on the unit. These controls modify the reverberant signals in es-
sentially the same way the individual channel tone controls modify the non-reverb, or "dry" tones. The reverb tone con- trols allow the user to change the reverberant sound to compensate for the reverberation of each room in which the system is used. In a "boomy" sounding room, decrease the Reverb Bass control or increase the Reverb Treble con- trol, or do both to equalize the reverb signals for the de- sired sound.
The individual channel reverb In-Out switches (7) are basically intended to allow the user the option of having reverb on one or more channels while retaining a "dry" (non-reverb) signal on the other channels. These switches can also be used to perform a variety of other functions which are described under Special Operating Instructions.
The Master Reverb In-Out switch allows instantaneous reverb turn-on or shut-off, no matter how the individual channel reverb selector switches are set. This feature al- lows the user to "pre-program" the console for reverbera- tion.
A phone jack marked "Reverb Switch" (16) is located on the rear panel of the console. This jack parallels the Master Reverb "In-Out" switch (4) and allows the reverb to be re- motely turned on and off when the Master Reverb switch is in the "In" position. The Master Reverb switch will always override the remote switch and turn off the reverb, so care should be taken to insure that the Master Reverb switch is in the "In" position if an external remote switch is desired to control the reverb switching. If an external remote switch is used, and is in the "Off" position, the Master Reverb "ln- Out" switch cannot override it and activate the reverb.
Since the remote switching is D.C., and no audio appears on this jack, any length of unshielded cable can be used between the Console and the remote switch without hum or noise. The remote switch can be any single pole, single throw switch.
VU Meter:
The VU Meter measures the voltage on the "Speaker" jacks and, with a given speaker load, indicates the Console output power to that load. A 3 db increase indicates a doubling of output power, while a 3 db decrease halves output power. The VU Meter Sensitivity Switch increases the sensitivity of the VU Meter by 14 db when set to the "Lo" position. With the Sensitivity Switch in the "Lo" posi- tion "0" VU on the meter corresponds to 4 volts on the "Speaker" jack, which is 2 watts with an 8-ohm load (two VABOO-S Speakers). In the "Hi" position "0" VU corre- sponds to 20 volts on the "Speaker" jack, which is 50 watts with an 8-ohm load.
With an 8-ohm speaker load (two VA300-S) zero VU is 50 watts. Output power for other VU readings is shown in the table below.
SENSITIVITY SWITCH IN "HI" POSITION
vu
+; -3
- 7
-10
SENSITIVITY SWITCH IN "LO" POSITION
vu
Power to 8-ohm load
4 watts 2 watts 1 watt 0.4 watts 0.2 watts
Power to 8-ohm load
100 watts 50 watts 25 watts 10 watts
5 watts
It should be noted that operation of the Console with the meter reading into the red portion of the scale does not indicate any type of overload. "Pinning" the meter, while not a good practice, will not damage it. If the Console is operated without a speaker load (nothing plugged into the "Speaker" jacks) the VU meter readings are meaningless because the Console is delivering zero power. Just disre- gard the meter readings if the Console is operated in this manner.
Auxiliary Hi-Level Output:
A phone jack on the rear panel marked "Aux. Hi-Level
Output" is provided for connections to tape recorders for making recordings, or to additional power amplifiers, such as the Shure Power Master PM300 Series. For specific in- structions for such connections, see the section marked Special Operating Instructions.
The signal at this jack is the same signal that drives the console power amplifier and is considered to be an auxil- iary, high impedance output for driving high-level, high- impedance inputs. Note that all the Console controls, Mas- ter Volume, Anti Feedback, Reverb, etc., affect this signal.
The interconnecting cable used with this jack should be a low capacitance, single conductor, shielded cable (such as Belden #8401, #8410, #a41 1).
Limit the cable length to 15m (50 ft) to avoid loss of high frequency signal and to reduce the possibility of hum pickup.
Microphone Level Output:
A microphone level output connector is provided on the
rear panel of the Console. This connector is a professional three-pin male audio connector (20). A "Lo Z-Hi Z" im- pedance selector switch (19) is located above the output connector. This screwdriver-slot, slide switch selects the
impedance of the microphone output. The signal at this connector is the same signal (but at mic, level) that drives the Console power amplifier and is designed to work into an amplifier or tape recorder microphone input. This output is useful for providing a signal feed to a house P.A. system for coverage in other rooms, or for low level fill in difficult coverage areas of irregularly shaped rooms.
With the "Lo Z-Hi Z" switch in the "Lo Z" position the microphone output connector is switched to a balanced low impedance transformer; connector Pins 2 and 3 are "hot" and Pin 1 is "ground." With the switch in the "Hi Z'' position the connector is sditched to provide a high impe- dance output; connector Pin 3 is "hot" and Pin 1 is "ground." See figure 4.
Echo:
Echo may be introduced into the Console by using an accessory echo device (such as an Echolette or Dynacord). To use an external echo device in conjunction with the Console, interconnect the two units as follows: attach low capacitance, single conductor, shielded cable to the Con- sole jack marked Echo "To Input." Connect the opposite
end of this cable to the echo device jack marked "Input" (Aux. High Level). Connect a similar cable to the echo de- vice jack marked "Output" (Aux. High Level) and connect the opposite end of this cable to the Console jack marked Echo "To Output."
Using the "Echo Gain" Control in conjunction with the level controls on the echo u.nit, the echo signal may be balanced with the gain of the Console so there is no change in level when the individual Reverb In-Out switches are operated.
When connected in the manner described, the individual channel Reverb In-Out switches will offer selective echo in addition to selective internal reverb. With the Master Re- verb In-Out switch in the "Out" position, the individual
TO CONSOLE ECHQ "TO IN- PUT' JACK
TO ECHO DEVICE
HIGH IMPEDANCE MICROPHONE
INPUT JACK
-
RESISTORS ARE 112 WATT 10%CARBON
FIGURE 5.
VA302 Series Vocal Master
.- SHIELD-,- _-__--L
FIGURE 4. Microphone Output Plug Connections.
If the low impedance output is to be used with an un- balanced input, such as an input that uses a phone plug or other connector with only two connections, connect Pins 1 and 2 of the Console microphone output connector to- gether. Use this as the "ground" and connect Pin 3 as the "hot."
It should be noted that the signal at this connector is "out-of-phase" with the Microphone Inputs. See page 6, lnput Connections, for information on phasing.
MIC. OUTPUT
MIC. OUTPUT
HIGH IMPEDANCE
MICROPHONE OUTPUT PLUG CONNECTIONS
channel Reverb switches will select "dry" (no echo) in the "In" position and "Echo" in the "Out" position.
Changing the Master Reverb In-Out switch to the "In" position will permit selection of echo (individual channel Reverb switch "Out") or reverb (individual channel Reverb switch "In").
The output signal of the Console at the jack marked Echo "To Output" is considered high level and is suitable for use with loads of 10 kilohms or greater. The jack marked Echo "To Input" presents a 40 kilohm load to the source and will accept high level signals. Some echo units employ inputs suitable only for very low level; in such cases, a
LOW IMPEDANCE (BALANCED LINE)
resistance pad (attenuator) will be required in the line from the Console to the echo device input. If the echo device in- put is suitable for only high impedance microphones a re- sistive pad consisting of a 100 kilohm and a 3.3 kilohm re- sistor is required. (See figure 5.) Almost all makes of echo units use different output levels; these may generally be compensated for by use of the gain controls on the echo unit and the "Echo Gain" control on the Console.
Tape Recording:
Tape recordings of the Vocal Master output can be made from either the "Microphone Level Output" or the "Auxil- iary Hi-Level Output" on the Console. To use the "Micro- phone Level Output" connect a cable from the Console to the Microphone lnput on the tape recorder. Set the Con- sole "Lo 2-Hi Z" impedance selector switch to match the impedance of microphones normally used with the tape recorder. Use the "Lo 2" position for microphones up to 1000 ohms, and the "Hi Z" position for microphones 1000 ohms or greater impedance.
See the section on Microphone Level Output for wiring instructions.
To use the "Auxiliary Hi-Level Output" on the Console, connect a cable to the Auxiliary Hi-Level lnput on the tape recorder. See the section on Auxiliary Hi-Level Output, page 10, for cable length and type. For stereo tape record- ings see page 13, Stereo Operation.
Playing Tapes:
To play back tape recorded material through the Con- sole, connect a cable from the tape recorder's High Level Output to the Echo "To Output" jack on the Console. Ad- just the Echo "Gain" control, the "Master Volume" control, and the tape recorder playback level control for the desired volume. Note that those lnput Channels on the Console that are switched to Individual Reverb "Out" are now turned off. See the section on Microphone Cuing on page 13.
Limit the cable length connected to this jack to 50 feet of low capacitance, single conductor, shielded cable (such as Belden #8401, #8410, #8411) to avoid loss of high fre- quency signal and to reduce the hum pickup.
An alternate method is to connect the high-level output of the tape recorder to a three-pin professional plug ("hot" lead to pin 3, shield to pin I), and connect the plug to a Shure Model A15LA Line lnput Attenuator. With the A15LA connected to a Console microphone input, 50 dB of attenu- ation is provided at that input.
Still another method is to use a Shure A95 Series Line Matching Transformer, with the auxiliary high-level tape recorder output attached to the high-impedance end and the low-impedance end attached to the Console micro- phone input. The Console Attenuator switch should be in the "In" position. NOTE: It may be necessary to add a Shure A15A Attenuator to provide an additional 15 dB of attenuation.
Musical Instruments:
Most electrified musical instruments may be amplified through the Vocal Master with great effectiveness. Place a microphone in front of acoustical, nonelectrified instru- ments, or in front of the instrument loudspeakers to "mike" an instrument. As an alternate direct connections may be used for instruments with a "pickup" or preamplifier output (such as a guitar or keyboard instrument). Connections are the same as for high impedance microphones, see page 11.
When the instruments play very loud, signals in excess of the Console preamplifier clipping level may be encoun- tered, and produce distortion. Should this occur, switch the input attenuator on that channel to the "In" position
and adjust the channel volume control for the desired level. See lnput Attenuator Switches, page 6.
High lmpedance Microphones:
High impedance microphones may be used with the Console by adding accessory matching transformers (Shure A95 Series) to the Inputs.
The Shure Model A95U Line Matching Transformer is terminated at the low impedance end with a professional three-pin male audio connector for direct connection' to the Console Inputs. The high impedance end of A95U Trans- former is supplied with an adapter to accept phone plugs. Limit the high impedance cable length to 6m (20 ft) to avoid loss of high frequency signal. If a longer cable is required use approximately 3m (10 ft) of high impedance cable be- tween the microphone and the matching transformer, and add as much cable as is required between the transformer and the Console Input.
Additional Inputs Using A Mixer:
If additional microphone inputs are required, a micro- phone mixer (such as a Shure M68 type) or a second Vocal Master Console may be used.
When using a microphone mixer for the additional in- puts, connect the mixer Lo lmpedance Mic. Output to one of the lnput connectors on the Console. The individual in- put control on the channel, bass, treble, volume, and re- verb, provide master control over the mixer inputs. See Figure 6.
FIGURE 6.
When reverb and external echo are not required, the mixer may be connected to the Echo "To Output" jack. With this arrangement the mixer Aux. High Level Output is connected to the Console Echo "To Output" jack. See Figure 7.
A VA302 CONSOLE
IJ FIGURE 7.
'Current A95 Line Matching Transformers have a smaller diameter low impedance end for direct plug-ln connections to the "Inputs." When using older A95A Line Matching Transformers connect a cable between the transformer and the Console "lnput."
Adjust the Echo Gain control and the mixer volume con- trols to matcti the gain of the Console inputs. With the mixer connected in this configuration the individual Reverb In-Out switches on the Console should be set to the "In" position. When these switches are set to the "Out" posi- tion, that individual channel will be muted, or "cued." See the description on "cuing." Still more inputs may be added by stacking additional mixers onto the first mixer. See the Mixer Operation Instructions.
Additional Inputs Using a Second Console:
A second Console may be used as a mixer to provide additional inputs.
Connect an accessory line matching transformer, Shure Model A95U, to the Echo "To Input" jack on the second Console. Connect a cable from the low impedance end of the transformer to an lnput on the original Console and set the lnput Attenuator on that input to the "In" position. See Figure 8.
use a PM300 Series Power Master amplifier and additional Speaker Columns. Generally two Speaker Columns should be connected to each amplifier. See Figure 9.
SPEAKERS
FIGURE 8.
At this point it should be noted that the microphones on the original Console are out of phase with those on the second Console. If the microphone pickups for the two Consoles are different sources, for instance the original Console is a vocal pickup and the second an instrumental pickup, this is not a problem.
For further information on Phasing see the section on lnput Attenuator Switches on page 6.
With this arrangement, the power amplifier section on the second Console is not being used. If additional power and coverage are required, this power amplifier section may also be used. See the section on additional power us- ing a second Console, Figure 10.
If it is necessary to use two Consoles on a permanent basis a factory authorized COMMON MIX. BUS MODIFI- CATION is available. Contact your Shure Dealer or the Shure Factory for further information on this.
Additional Power or Area Coverage:
In those applications which require more power than one Vocal Master system is able to deliver, such as very large auditoriums and stadiums, and in those installations where the audience is so widespread, such as Theatre-in-the- Round and for coverage in adjoining rooms or when more than three speaker columns are required, it is advisable to
SPEAKERS
FIGURE 9.
To use the Power Master Amplifier, connect a cable from the Console jack marked "Aux. Hi-Level Output" to an in- put on the Power Master Amplifier. The cable used should be limited to 15m (50 ft) of low capacitance, single conduc- tor, shielded type (such as Belden #8401, #8410, #8411).
Set the Volume Control on the Power Master to "7" to obtain the same amplification level from both the Console and the Power Master when identical speaker loads are employed on each amplifier. The output of the Power Mas- ter will "follow" all control settings of the Console. Addi- tional Power Master Amplifiers may be added to the sys- tem by connecting a cable from the unused input jack on the last Power Master to one of the input jacks on the next Power Master. See Figure 9. NOTE: The unused input jack on the last Power Master in the "chain" can then be used for tape recording. See the Special Operating Instructions on Tape Recording.
To use a second Console in place of a Power Master to obtain additional power, connect a cable from the original Console jack marked "Aux. Hi-Level Output" to the jack marked Echo "To Output" on the second Console. See Figure 10.
SPEAKERS
FIGURE 10.
Set the controls on the second Console as follows: Anti Feedback'Switches to "Out," Master Reverb Switch "Out," Individual Volume Controls to "0," and the Master Volume to "5." Adjust the Echo "Gain" Control to approximately 113 rotation from the C.C.W. off position, and use this con- trol as a volume control to obtain the same amplification level from both of the Consoles. Once the Echo "Gain" Control is preset, the output of the second Console will "follow" all control settings of the original Console. Small changes in amplification level on the second Console can be made by adjusting its Master Volume Control.
An additional Console, PM300 or tape recorder can be connected to the "Aux. Hi-Level Output" jack on the second Console.
Microphone Cuing:
Microphone "cuing" may be preset by using the indi- vidual Reverb "In-Out" switches to reduce the volume of, or turn off an unused individual microphone channel. This is useful when it is desired to preset the individual volume controls but only have one or two microphones "live" at a time. This allows tighter control of feedback, or additional control to avoid pickup from off-stage microphones.
Insert an unwired phone plug into the Echo "To Output" Jack. With the individual Reverb switch in the "In" position, the channel will operate normally. In the "Out" position, the channel level is reduced or turned off. The level of the "Out" or "Cued" channel is controlled by the "Echo Gain" control; turning this control fully counterclockwise turns off the "Cued" channel. Returning the individual Reverb "In-Out" switches to "In" restores the channel to the nor- mal level.
For remote "Cuing" on and off, plug a foot switch into the Echo "To Output" Jack on the Console. Turn the "Echo Gain" control fully clockwise. With the foot switch in the "On" position, the channels will operate normally. With the foot switch "Off" those channels switched to individual Reverb "Out" are turned completely off. This is useful for remotely turning on and off preselected channels (Micro- phones). The cable used with the foot switch should be limited to 15m (50 ft) of low capacitance, single conductor,
'As a general rule stereo sound reinforcement of this type is quite dis- tracting to listen to and is recommended only for special effects.
shielded type (such as Belden #8401, #8410, #8411) to avoid high frequency signal loss and to reduce the possi- bility of hum pickup in the cables.
Stereo Operation:*
Stereo operation may obviously be obtained by using two Vocal Master systems without any interconnections. If it is desired to have one of the microphones connected to both systems, simply use a "Y" connector on that microphone and feed its signal to one Input on each Console. For mak- ing stereo tapes, the "Aux. Hi-Level Output" jacks, one on each Console, may now be connected to the left and right Auxiliary Inputs, respectively, on a stereo tape recorder.
Alternatively, stereo may be accomplished by using one system and one Power Master with additional speakers. A connection is made from the Console jack marked Echo "To Input" to an input of the Power Master. Those input channels of the Console which are to be reproduced through the Console speakers will require that the indi- vidual channel Reverb "In-Out" switches be in the "In" position. The channels on which the switches are in the "Out" position will be heard at the speakers connected to the Power Master. This may be used for a special echo effect, like "throwing" a voice from the rear of the room.
Stereo recordings may also be made using one Vocal Master Console and one Power Master. One channel of the stereo tape recorder would be fed from the Console jack marked "Aux. Hi-Level Output," the other channel would be fed from the open input jack of the Power Master. NOTE: Reverberation can be added to only those chan- nels that are being reproduced by the speakers connected to the Vocal Master Console.
A very convenient way of recording with a stereo tape recorder is to record the vocals on one tape channel and the instruments on the other tape channel. Connect the Console "Microphone Level Output" or the "Aux. Hi-Level Output" to the right channel of the tape recorder; see page 11 Tape Recording. A separate microphone is connected to the left channel microphone input of the tape recorder; an omni-directional microphone suspended from the ceil- ing is recommended.
WPUT
IN , 1508 ATTEN
BASS& IND
-:-I ATTENLATOR
- T R EC BO L N E T ' L
-
VcOoLNUMTEL
AUX HIGH LEVEL
OUTPUT
MIC LEVEL OUTPUT
(HIGH/ LOW 2 )
OUT CJ'yLITCH
r
I
-
, MASTER
-. INTENSITY
-
REVERB BASS a TREBLE CONTROLS
REVERB
Amplifier Service (See Guarantee):
The Vocal Master Console uses
est quality, operating well within their respective ratings to assure long life. CAUTION: There are no user serviceable parts inside. Refer servicing to qualified service personnel.
Amplifier Removal:
To remove the amplifier from its carrying case, remove the three screws located at the top front edge of the case and the six screws, four within the plastic feet, on the bottom of the case. Push the amplifier slightly forward
from the back to permit access to the front panel. (Note: Uncoil the cable before pushing the chassis. Push against amplifier chassis not against the grille on the back,) The entire amplifier may be pulled forward at this point and separated from the case.
Front Panel Removal:
To ease servicing of components on the front panel, re- move the four screws on the bottom rim of the front panel. (Note: Stand amplifier on end with transformer side down.) Figure 12, Page 15, shows the amplifier with the front panel removed and tilted to a convenient servicing position.
REVERB SPRING
CONTROL i~ '.
I
0
' TO VA302-C SERIES FUNCTIONAL DIAGRAM
FIGURE 11.
VA302 Series Vocal Master
the high-
INDIVIDUAL REVERB SWITCH
JACK SWITCH OPERATES WHEN PLUG IS INSERTED
v U METER
SPEAKERS
Driver Transistors:
The driver transistors Q33 and Q34, Figure 12, Page 15, are located on the amplifier chassis. Before removing these transistors, write down the lead color and location at each transistor solder junction. If replacing transistors, apply type 120 Wakefield thermal joint compound to each side of the insulation wafer to provide good thermal transfer from transistor to chassis. After replacement and before con- necting transistor leads, check transistors with an ohm- meter between case and chassis; there should be no con- tinuity. Be sure that these transistors are not inverted in the circuit; they are not identical devices. Q33 is an NPN transistor, while Q34 is PNP transistor. Refer to the lower right corner of the circuit diagram, Figure 17, Page 21 for terminal code. NOTE: when replacing driver transistors, perform the following modification (if not already per- formed): solder a 3.3k, Y2W resistor across the terminals to which the white and black leads of transformer T2 are connected. Add a second ground wire from the terminal
nearest the front of the unit to which resistor R21 is con- nected, through the chassis grommet, to the ground on the Speaker Output jacks (same path as existing wire).
Output Transistors:
The output transistors Q35 through Q38, Figure 12, Page 15, are located on the black finned heat sinks. Replace- ment procedure is the same for the driver transistors, Q33 and Q34.
NOTE: The output transistors, Q35 through Q38, must be matched for current gain and part number. When replac- ing output transistors be sure to replace with devices which have the same gain code as the original transistors. Shure transistors are coded either by the last letter in the part number or a color-dot on the top of the transistor.
FIGURE 12.
Blue Dot = A Red Dot = B Orange Dot = C Yellow Dot = D Green Dot = E
Brown Dot = F Pink Dot = G Violet Dot = H
Black Dot = J White Dot = K
Small Signal and Predriver Transistors:
Transistors Q1 through Q30, Figure 14, Page 16, and Q31
and (232, Figure 12, Page 15, are mechanically supported by their leads. When replacing these transistors, it is im- perative that proper lead configuration be followed. A min- imum of soldering heat should be used to avoid damage to the transistor. Refer to the lower right corner of the circuit diagram, Figure 17, Page 21, for lead code.
Diodes:
Diodes D6 and D7, see Figure 12, Page 15, are located
on the black finned heat sink with the output transistors. Special care is required to insulate these diodes from the heat sink while providing good thermal transfer from sink to diode. Heat shrinkable tubing or "spaghetti" should be placed over the diode and connecting leads; the diode
should be securely clamped to the heat sink with the clamp ...
Check Transistors and Diodes:
Defective transistors and diodes may be located by use of an ohmmeter. Polarity of the ohmmeter must be verified before these checks are made.
With a known diode orientation, measure the diode re- sistance in the forward and reverse directions. The lowest meter reading will establish the probe at the cathode end (schematic symbol arrow points to cathode) as the "minus" probe while the other probe will be "plus." Some ohm- meters are not polarized in this manner with relation to "volts plus probe" and "volts minus probe."
To check transistors, the ohmmeter should be set to the
100 ohm or 1,000 ohm scale. Small signal transistors (Q1
through Q32) must be removed from the circuit before
testing. Transistors mounted with screws (Q33 through
FIGURE 13.
FIGURE 14.
(238) may be tested in place; however, the leads to these
...,
rranslsrors rnusr De removea.
If all conditions in the following table are met, the tran- sistor may,be considered free of any gross defect; if any of the following conditions are not met, the transistor should be replaced. See lower right corner of circuit diagram, Figure 17, Page 21, for transistor terminal code.
Lamp Replacement:
The two lamps I 2 and 13, Figure 12, Page 15, which pro- vide illumination of the front panel controls are 115 to 125 volt, 15 watt incandescent bulbs. These bulbs are soldered and epoxied into the molded plastic sockets in order to meet Underwriters' Laboratories requirements. The assem- bly may be removed by unsoldering the lamp leads at the terminal strips and removing the screw that holds the socket to the chassis.
Reverberation Assembly:
The Reverberation Assembly M2, Figure 13, Page 16, may be removed and returned to the factory Service De- partment for repair if a malfunction should occur. The am- plifier can be operated without this assembly. To eliminate possible damage, or shock hazard, the plug-in cables should be temporarily inserted in the nylon inserts nor- mally used to mount this sub-assembly. If extensive dam- age has occurred, a replacement Reverberation Assembly may be ordered through the dealer or from the factory Service Department.
Replacement Parts:
Parts that are readily available through local electronic parts distributors are not shown on the accompanying Parts List. Their values are shown on the circuit diagram. The special custom made parts are shown on the Parts List.
The commercial alternates shown on the Parts List are not necessarily equivalents, but may be used in the event that direct factory replacements are not immediately avail- able. To maintain the highest possible performance and reliability, Shure factory replacement parts should be used. When ordering replacement parts, specify the Shure Re- placement Kit Number, description, product model number and serial number.
OHMMETER CONNECTIONS
"Plus" "Minus" Lead Lead
Collector Emitter Emitter Collector Collector Base Emitter Base Base Collector Base Emitter
OHMMETER READING
With the ohmmeter "plus" probe on the anode end of a diode,andthe"minus" probeonthecathodeend,theohm- meter should read approximately 2000 ohms or less. With the meter probes reversed, a reading of about 10,000 ohms or more should occur. If either of these conditions is not met, the diode should be replaced.
Power Drain Resistor (R,):
The following condition may occur after replacement of driver transistors Q33 and Q34, output transistors Q35 through Q38, or diodes D6 and D7. If the unit appears to operate at an excessively high temperature or thermally recycles after about 10 minutes with no signal input, the "cold" standby power drain may be excessive (up to 20 watts higher than normal; a higher power drain indicates further circuitry problems). The nominal power drain under these conditions should be 60 watts; if the meas- ured figure exceeds 75 watts, insert a resistor (R,) in parallel with the 56-ohm resistor between the base of transistor Q33 and the junction of diodes D6 and D8 (figure 17, page 21). RsEL(1/2W, 10%) should be either 180 ohms to decrease the power consumption by 20 watts, or 82 ohms to decrease the power consumption by 30 watts.
EQUIPMENT DESIGNED FOR USE WITH
THE VOCAL MASTER VA302 CONSOLE SERIES
VA300-S Vocal Master Speaker Column VA301-S Vocal Master Monitor Speaker PM300 Power Master Booster Amplifier PM3OOE Power Master Booster Amplifier PM300E6 Power Master Booster Amplifier A3PC Soft Cover Set
A3PC-C Console Soft Cover
A3PC-S Speaker Column Soft Cover A31PC-S Monitor Speaker Soft Cover ASS-C Fold-Up Console Stand
-
A3S-S Speaker Stand
-
A3S-T Speaker Stand
A50XC 15m (50 ft) Speaker Extension Cable A95 Series Line Matching Transformers
GUARANTEE: This Shure product is guaranteed in normal use to be free from electrical and mechanical defects for a period of one year from the date of purchase. Please retain proof of purchase date. This guarantee includes all parts and labor.
SHIPPING INSTRUCTIONS: Carefully repack the unit and return it prepaid to the factory. If outside the United States, return the unit to your authorized Shure Service Center for repair. The unit will be returned to you prepaid.
SERVICE: If information or service should be required, contact your local Shure Vocal Master dealer explaining your difficulty in detail. In addition, the Shure factory service department will be ready to assist you immediately upon request.
N.P.N. Transistor
High
High High High Low - Low Low High
Low
P.N.P. Transistor
High
-
VA300-S Speaker Servicing:
1. 2.
3. 4.
5.
6.
7.
Unplug cables from speaker jacks.
Using an ohmmeter, measure the resistance of the speaker column. The resistance should be between 12 and 16 ohms. Readings outside of these limits indicate possible failure.
Remove back of cabinet.
Disconnect one end of the lead connected between the two 10 inch loudspeakers.
Using an ohmmeter, measure resistance of the voice- coil of each loudspeaker individually. Each 10 inch speaker should measure between 12 and 16 ohms. Each 8 inch speaker should measure between 5 and 8 ohms. Readings outside of these limits indicate possible failure.
Apply 60 Hz, 1 to 10 volts, to each of the six speak- ers individually. Any buzzes or rattles indicate pos- sible failure. The speakers should all sound gener- ally alike with a slight difference between the 8 inch and 10 inch loudspeakers.
Reconnect lead disconnected in Step 4. Install back of cabinet tightly.
REPLACEMENT PARTS LIST FOR VASOO-S SPEAKER COLUMN
REPLACEMENT KIT CONSISTS OF
m
QTY. PART NO.
1 80A207
1 80A208
1 90A1375 1 946462
1 90A1373 1 95A436
4 65A1001A
-
- 39A279
-
- 48A20
DESCRIPTION
8 Inch Loudspeaker
10 Inch Loudspeaker Rear Panel Assembly Column Cabinet
Cable and Plug Assembly Handle Assembly Bumper (Plastic Foot) Name Plate
Side Rail
'Recommended replacement cable connectors (not available from factory. Switchcraft part numbers given:) Straight Locking Plug: $ 2 8 2 Right ~ n ~ l ; Lockin Plug: #228; Locking Extension Jack (for Extension cable Assern- bly): $123.
COLOR CODED TERMINAL
FIGURE 15.
FIGURE 16.
I
I
I
COMMERCIAL
ALTERNATE I
1
1
RKC47
RKC61 ---
RKC37 RKClO RKC44t RKC43 RKC42 RKC41 RKC40 --- ---
RKC35 RKCl47 1
RKC28 RKC84
51A215 1 51A241
51A217 90H2150
1
T2 T3-T9
1 1
IT P .
QTY. 1 PART NO.
DESCRIPTION
Capacitor, 2500 x 100 Capacitor, 4000 x 60
Silicon Rectifier, 3A., 200 V. Zener Diode, 22V,, 1 W., 5% Silicon Rectifier, 100 V., %A. Zener Diode, 3.6 V., 1 W., 5% Germanium Diode
Silicon Diode, 50 V., '/PA.
A.C. Fuse (VA302 and VA302E) A.C. Fuse (VA302E6 only)
for 200-240 volts
A.C. Fuse (VA302E6 only)
for 100-140 volts
D.C. Fuse (VA302 and VA302E) D.C. Fuse (VA302E6 only) Wired in A.C. Fuse (VA302 only)
Pilot Lamp (VA302 only)
Pilot Lamp (VA302E and VA302E6) Lamp Assembly
Connector, Mic. Input
Phone Jack
Phone Jack
Phone Jack
Connector Mic. Output
3 Wire A.C. Line Cord and Plug
(VA302 only)
Line Cord (VA302E only) Line Cord and Connector
(VA302E6 only)
Reverberation Assembly
Anti Feedback Inductor Assembly VU Meter
Handle Assembly
Console Cabinet
Volume Control Knob Assembly Treble Control Knob Assembly Bass Control Knob
Knob and Screw (Line Cord
Storage Spindle) Shield
Bumper (Plastic Foot) Fuse Holder (VA302 only) Fuse Holder (Screw Slot,
VA302E only)
Fuse Holder (5 x 20mm VA302E6 only) A.C. Chassis Power Connector
(VA302E6 only)
Cabinet Upper Side Rail Cabinet Lower Side Rail Transistor (Replaces 86A327)
Transistor
Transistor 110 V. BVceo Min. Transistor 110 V. BVCEOMin. Transistor 105 V. BVcxo Min. (Mutually Interchangeable) Transistor 110 V. BVcco Min.,
Potentiometer, Dual 50K/50K Potentiometer, 50K.
Potentiometer, 50K. Potentiometer, 2.5K. Resistor. .43 ohms, 5 W.
Resistor, .20 ohms, 5W.
Resistor, .l2 ohms, 5 W.
Resistor
Toggle Switch (VA302 and VA302E) Toggle Switch
(2 position VA302E6 only) Thermostat .
Slide Switch (Screw Slot) Rocker Switch, Chrome Rocker Switch, Redlorange Rocker Switch, Orange
Rocker Switch, Orange/Yellow Rocker Switch, Yellow
Slide Switch, Black Voltage-Selector Switch
(VA302E6 only)
Power Transformer (VA302 only) Power Transformer (PMSOOE and
PM300E6)
Feedback Transformer Mic. Transformer Assy.
R1-R6, R14 I R7-R12,
/
RKC58 RKC59 1
RKC57 RKC6O ---
46A017 1 46A016
NONE
NONE
Motorola No. 1N4721
Motorola No. 1N4748A Motorola No. IN4002
Motorola No. 1N4729A
Sylvania No. 1N48, IN60 Motorola No. 1N4001
Littelfuse 3AG/3A/SB (Slo-Bio) 5 x 20mm, 1.6 AT, 250 V.
5 x 20mm, 3.0 AT, 250 V. Littelfuse 3AGl5A
5 x 20mm, 5.0 A, 250 V. Bussmann MDVI5AISB (Slo-Blo)
Pig-tail
Leecraft No. 36N1311-6 Leecraft No. 36HN-1311-7W NONE
Switchcraft No. C3F Switchcraft No. 12-A Switchcraft No. 14-8 Switchcraft No. 11 Switchcraft No. C3M
NONE
NONE NONE
Gibbs No. 4L (Insulated Output) NONE
NONE
NONE
NONE NONE NONE NONE NONE
NONE
Littelfuse No. 342014 Littelfuse No. 341001
SchurterType FEB Switchcraft No. EAC-301
NONE
NONE
Motorola No. MPS-6521
Texas Inst. No. 2N3711 Motorola No. MPS-3392
RCA No. 40349
RCA No. 2N3441
Motorola No. 2N3741 Selected
RCA No. 2N3773
NONE 1 NONE
NONE NONE NONE
NONE
NONE
Workman No. FRT-2 Cutler-Hammer No. 7563K5 Marquardt Type No. 0132
NONE
Continental-Wirt No. G-326 NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE 1 NONE
NONE NONE
Rl6
..
REPL. KIT NO.
REPLACEMENT PARTS LIST FOR VA302-C SERIES CONSOLES
--
---
REPLACEMENT KIT CONSISTS OF:
NOTE: The Commercial Alternates shown above are not necessarily equivalents but may be used in the event that direct factory replacements are not immediately available. To maintain the highest possible performance and reliability, Shure Factory Replacement Parts should be used.
'When ordering 86A332 or 868332,specify current gain code. See Page 15.
"Parts listed as RKC Kit8 should be ordered by that kit number. Any orden received for plece parts where RKC Kit number is shown will be shlpped In RKC quantities.
+For gray switch order Part No. 55A73F.
19
D.C. Voltage Measurements:
Check the DC voltages first, because any deviation from the nominal voltages will affect the AC voltage. In the power amplifier, Q31 to Q38, the key DC voltages are 9 4 (col- lector of Q33, 035, and Q37), -22 (collector of Q31), and the split voltage at the junction of R17, R19, R20, and R22. If these three key DC voltages are correct, then pro- ceed with the AC voltage measurements.
The numbers within the symbols o on the circuit dia- gram denote the D.C. voltage at that point with the follow-
13. Transistor voltage measurements for Q20 through Q27 must be made with master reverb switch and individual channel reverb switches in the "IN" position.
14. A.C. voltage measurements may vary ?:50°h from the values shown.
15. For A.C. measurements on Q25, Q26, and Q27, the frequency may be varied t 1 0 0 Hz. to obtain the A.C. measurements shown.
16. For VU Meter specifications, see page 9.
Ohmmeter Measurements:
With the A.C. line cord unplugged and the power switch in the "OFF" position, the following ohmmeter measure- ments may be made:
1. Reverberation Assembly M2 input and output coils approximately 180 ohms.
2. Anti feedback Inductors M3 approximately 300 ohms.
3. B - to ground approximately 50 ohms
4. Ohmmeter plus probe to the junction of R17, R19, R20, and R22, ohmmeter minus probe to ground: greater than 100 ohms.
5. Ohmmeter plus probe to B I , ohmmeter minus probe to the junction of R17, R19, R20, and R22: greater than 100 ohms.
6. To test transistors and diodes, see page 16.
Shure part numbers are not shown in the parts list ac- companying the circuit diagram if parts are readily avail- able through local electronic parts supply distributors. In these instances, the circuit diagram will show the value of the standard parts.
All capacitor values are shown in microfarads. All non- electrolytic capacitors are to be 100 volts or more unless otherwise specified in the circuit diagram. Electrolytic ca- pacitors are shown in microfarads and volts.
All resistor values are shown in ohms. Resistors are all to be 10% tolerance unless specifically noted on the cir- cuit diagram.
Resistors shown in the upper two lines of circuitry on the diagram are '/4 watt unless otherwise specified. Resistors shown in the lower line of circuitry are l/2 watt unless other- wise specified.
The following ground symbols denote:
Chassis Ground
ing 1.
2.
3. 4.
5. 6.
test conditions:
Voltages measured at points indicated with respect to chassis, unless otherwise indicated.
Line voltage - VA302-C: 120v. 60 Hz. VA302E-C: 120/240~5. 0/60 HZ.
VA302E6-C: 100, 120, 140, 200, 220, or 240v. 50/60 Hz.
No input signal applied.
D.C. voltage measurements may vary &20% from the values shown.
Measured with a VTVM of 11-megohms input impe- dance.
Q27 transistor voltages on the circuit diagram are with the master reverb switch in the "IN" position. With the master reverb switch in the "OUT" position, Q27 volt- ages are: emitter 4.0, base 0.0, and collector 22.0.
A.C. Voltage Measurements:
The numbers within the symbols on the circuit dia- gram denote the A.C. voltage at that point with the follow- ing test conditions:
1. Voltages measured at points indicated with respect to chassis, unless otherwise specified.
2. Line voltage - as specified above.
3. 1,000 Hz. signal applied to input, in "IN" position, at 0.8 millivolts.
4. Measured with an A.C. VTVM of 1.0 megohms or greater input impedance.
5.
Noninductive load of 8 ohms, 200 watts connected to speaker output jack for Q31 through Q38.
6. Echo input and output jacks to be open; echo gain control set to maximum.
7. All anti feedback switches set to "OUT" position. 8. Reverb intensity set to minimum.
9. All tone controls set to 12 o'clock position.
10. All volume controls set to maximum.
11. Master reverb switch set to "OUT" position except as
noted.
12. Individual channel reverb switches set to "OUT" posi- tion except where noted.
1
Notes to Circuit Diagram
Preamplifier Ground
Reverb
Driver Ground
--
I VA302-C CIRCUIT DIAGRAM I
FIGURE 17.
