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Adjust the Echo Gain control and the mixer volume con-

trols to match the gain of the VA300 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” position, that indi-

vidual channel will be muted, or “cued.” See the description

on “cuing.” Still more inputs may be added by stacking addi-

tional mixers onto the first mixer. See the Mixer Operation

Instructions.

Additional Inputs Using a Second VA300-C:

A second VA300 Console may be used as a mixer to provide

additional inputs. Connect the Echo “To Input” jack on the

second Console to an Input jack on the original Console and

set the Input Attenuator switch on that input to the “Inst.”

position. See Figure 7.

Figure 7

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 

Low

Impedance Microphones 

on page 10.

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 using a second Con-

sole.

If it is necessary to use two consoles on a permanent basis a

factory authorized COMMON MIX. BUS MODIFICATION 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

VA300 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 use a

PM300 Power Master amplifier and additional Speaker Col-

umns. Generally two Speaker Columns should be connected to
each amplifier. See Figure 8.

Figure 8

To use the PM300 Power Master Amplifier, connect a cable

from the VA300 Console jack marked “To Tape Recorder” to

an input on the PM300 Amplifier. The cable used should be

limited to 15m (50 ft) of low capacitance, single conductor,

shielded type (such as Belden #8401, #8410, #8411).

Set the Volume Control on the PM300 to “7” to obtain the

same amplification level from both the VA300 and the PM300

when identical speaker loads are employed on each amplifier.

The output of the PM300 will “follow” all control settings of

the VA300 Console. Additional PM300 Amplifiers may be

added to the system by connecting a cable from the unused

input jack on the last PM300 to one of the input jacks on the

next PM300. See Figure 8. NOTE: The unused input jack on

the last PM300 in the “chain” can then be used for tape
recording. See the Special Operating Instructions on 

Tape

Recording.

To use a second VA300 Console in place of a PM300 to

obtain additional power, connect a cable from the original

VA300 Console jack marked “To Tape Recorder” to the jack
marked Echo “To Output” on the second VA300 Console. See

Figure 9.

Figure 9

11

Summary of Contents for Vocal Master VA 300

Page 1: ...VA 300 OPERATING AND SERVICE MANUAL Manufactured by SHURE BROTHERS INC 222 Hartrey Avenue Evanston Illinois 60204 U S A Copyright 1978 Shure Brothers Inc AL404 RE 27A819 Printed in U S A...

Page 2: ...eble 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 nominal 2 V at 50 watts to speakers Clipping Level 4 V...

Page 3: ...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 cir cuitry design protects th...

Page 4: ...olume Control 9 Thermal Overload Indicator Lamp 10 On Off On Power Switch Figure 2 Rear Panel Controls and Connections Refer to Figure 2 11 Line Cord Storage Spindles 12 A C Line Cord 13 D C Fuse 3AG...

Page 5: ...O to whichever 7 8 9 10 11 On position results in the least amount of hum coming from the speakers Now turn up the other Individual Channel Volume Controls 5 which are being used By use of the Indivi...

Page 6: ...weight inherent in such transformers The speaker output vol tage 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 vol...

Page 7: ...o 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...

Page 8: ...flat sounding voice It is often used to great advantage to reduce high frequency acoustic reverberation in reflective rooms The Master Volume control 8 adjusts the output level of the total mixed outp...

Page 9: ...perated 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 Reverb In Out switch in...

Page 10: ...put jack the low impedance end is terminated with a Cannon type 3 pin female connector The main advantage of low impedance microphones is that virtually unlimited cable lengths may be used whereas hig...

Page 11: ...TION 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 VA300 Vocal M...

Page 12: ...tems simply use a Y connector on that microphone and feed its signal to one Input on each Console For making stereo tapes the To Tape Recorder jacks one on each console may now be connected to the lef...

Page 13: ...dge 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 be...

Page 14: ...he following modifica tion if not already performed place insulated tubing over the leads of a 3 3k 1 2W resistor and solder it across the terminals to which the white and black leads of transformer T...

Page 15: ...ctive 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 resist ance in...

Page 16: ...a malfunction should occur The amplifier 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 norma...

Page 17: ...hms Read ings outside of these limits indicate possible failure 6 Reconnect lead disconnected in Step 3 Install back of cabinet tightly REPLACEMENT PARTS LIST FOR VA300 S SPEAKER COLUMN REP REPLACEMEN...

Page 18: ...A018 Potentiometer 50K R15 RKC60 1 46A020 Potentiometer 2 5K R17 R18 45EC439B Resistor 43 ohms 5 W R19 R21 R20 45EC209B Resistor 20 ohms 5 W R22 45EC129B Resistor 12 ohms 5 W R23 RKC47 1 45A38 Resisto...

Page 19: ...ALTERNATE POWER SUPPLY INCORPORATED IN EARLY PRODUCTION UNITS Figure 17 19...

Page 20: ...ume controls set to maximum 11 Master reverb switch set to OUT position except as noted Chassis Ground Preamplifier Ground 12 Individual channel reverb switches set to OUT pos Reverb ition except wher...

Page 21: ...VA300 C CIRCUIT DIAGRAM ISSUE 6 21 Figure 18...

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