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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 )   a n d   ( 6 ) .   s e t   i n   t h e   “ f l a t   r e s p o n s e ”   p o s i t i o n
(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 compart-

ments in the VA300-S Speaker Columns. Insert and lock
the right angle phone plug on the cable into either of

the two parallel-wired phone jacks; one on each Speaker

Column. Connect the other end of each cable to the

j a c k s   o n   t h e   r e a r   p a n e l   o f   t h e   C o n s o l e   m a r k e d

“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).

T h e   V A 3 0 0   i s   d e s i g n e d   t o   o p e r a t e   w i t h   a n y   h i g h

q u a l i t y   d y n a m i c   o r

r i b b o n - t y p e   h i g h   i m p e d a n c e

microphone. For low impedance microphones see page

1 0 .

5. Set all six Input Attenuator Switches (21) on the rear

panel of the Console to “Mic.” These switches should

generally be 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

7.

8.

9.

10.

11.

“ O n ”   p o s i t i o n   r e s u l t s   i n   t h e   l e a s t   a m o u n t   o f   h u m

coming from the speakers.

N o w   t u r n   u p   t h e   o t h e r   I n d i v i d u a l   C h a n n e l   V o l u m e

Controls (5) which are being used. By use of the Indivi-

dual Channel Volume Controls (5), the microphones

may be balanced for level so that the sound coming
from the speakers is in proper balance for each micro-
phone. Increasing or decreasing the 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-

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 condi-
tions, 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

“ 4 ”   S e t   t h e   M a s t e r   R e v e r b   s w i t c h   ( 4 )   t o   t h e   “ I n ”

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”

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
volume of all channels simultaneously without affecting
t h e   “ b a l a n c e , ”   o r   “ m i x . ”   N O T E :   W i t h   t h e   C o n s o l e

driven at or near full power, pilot lamps will dim or vary

in brightness; this is a normal condition.

5

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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