Instruction/ maintenance manual of the product VA 300 Shure
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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.
VA300 SPECIFICATIONS VA300-C Console Amplifier Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . All silicon transistor mixer/power amplifier Power Output . . . . . . . . . . . 100 watts continuous (RMS); (to 8 ohm load, see Figure 3, Page 7) Voltage Gain .
VA300-C Console (cont’d) Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 volts, 60 Hz. 80 watts maximum with no signal in. 180 watts with 1 KHz. signal and 100 watts output 400 watts maximum operating -7°C to 43°C (20°F to 110°F) without derating Power Consumption .
Figure 1 Front Panel Controls (Refer to Figure 1) 6. Individual Channel “Treble & Bass” Controls (Six, Dual 1. “Anti-Feedback” Switches (Four). 2. “Reverb Intensity” Control. 3. “Reverb Treble & Bass” Controls (Dual Concentric).
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).
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 micro- phone.
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.
Thermal Overload/Ventilation: The VA300 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.
A phone jack marked “Reverb Switch” (17) 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 remotely turned on and off when the Master Reverb switch is in the “In” position.
Phonographs: To connect a” phonograph having a magnetic cartridge, and no preamplifier, to the VA300, attach a cable from the phonograph output to one of the six Input jacks on the Console. Set that channel’s Input Attenuator Switch to the “Mic.
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.
Set the controls on the second VA300 Console as follows: Antifeedback 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 1/3 rotation from the c.
VA300-C FUNCTIONAL DIAGRAM Figure 11 VA300 Vocal Master SERVICE INSTRUCTIONS Amplifier Service (See Guarantee): The VA300 Vocal Master Console uses components of the highest quality, operating well within their respective ratings to assure long life. CAUTION: There are no user serviceable parts inside.
Driver Transistors: Figure 12 Output Transistors: The driver transistors Q33 and Q34, Figure 12, Page 14 are located on the amplifier chassis. Before removing these transistors, write down the lead color and location at each transistor solder junction.
Figure 13 Figure 14 Small Signal and Predriver Transistors: Transistors Q1 through Q30, Figure 14, Page 15 and Q31 and Q32, Figure 12, Page 14 are mechanically supported by their leads. When replacing these transistors, it is imperative that proper lead configuration be followed.
OHMMETER CONNECTIONS OHMMETER READING “Plus” Lead “Minus” Lead Collector Emitter Collector Emitter Base Base Emitter Collector Base Base Collector Emitter N.
VA300-S Speaker Servicing: 1. Unplug cables from speaker jacks. 2. Remove back of cabinet. 3. Disconnect one end of the lead connected between the two 10 inch loudspeakers. 4. Apply 60 Hz, 1 to 10 volts, to each of the six speakers individually. Any buzzes or rattles indicate possible failure.
REPLACEMENT PARTS LIST FOR VA300-C CONSOLE ** REPLACEMENT KIT CONSISTS OF: ITEM REPL. KIT NO. QTY. PART NO. DESCRIPTION C1 RKC26 1 86A631 Capacitor, 2500 x 100 C2 RKC27 1 86B631 Capacitor, 4000 x 60 D1-D4 RKC46 4 86A406 Silicon Rectifier, 3A., 200V. D5 RKC22 1 86A408 Zener Diode, 22V.
ALTERNATE POWER SUPPLY INCORPORATED IN EARLY PRODUCTION UNITS Figure 17 19.
Notes to Circuit Diagram 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 section, Q31 to Q38, the key DC voltages are +94 (collector of Q33, Q35, and Q37).
VA300-C CIRCUIT DIAGRAM ISSUE 6 21 Figure 18.
An important point after buying a device Shure VA 300 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Shure VA 300 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Shure VA 300 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Shure VA 300 you will learn all the available features of the product, as well as information on its operation. The information that you get Shure VA 300 will certainly help you make a decision on the purchase.
If you already are a holder of Shure VA 300, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Shure VA 300.
However, one of the most important roles played by the user manual is to help in solving problems with Shure VA 300. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Shure VA 300 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
