Shure m62v schematic

222 HARTREY AVE • EVANSTON, ILL. (60204) U.S.A.

AREA CODE 312/328-9000 • CABLE SHUREMICRO

MODEL M62V AUDIO LEVEL CONTROLLER

DATA SHEET

MODEL M62V

AUDIO LEVEL CONTROLLER

GENERAL:

The “Level-Loc” Audio Level Controller is basically

a low noise preamplifier with unity gain from micro-

phone level in to microphone level out or 60 db of voltage gain from Hi Imp. microphone level in to Aux. Output. The input and microphone level output contain matching transformers so either high or low impedance may be selected. In addition, a high impedance Aux. Output is provided capable of driving any high impedance amplifier, mixer or tape recorder input requiring 1 volt or less. This preamplifier has the additional capability of reducing its gain as the input signal increases, thereby ho/ding the output signal constant. After a predetermined input level is reached (threshold) the output level is “Locked”, that is, it remains constant even if the input signal increases by as much as 100 times (40 db). This reduction in gain, which results in a constant output level, is obtained without introducing significant distortion or transients into the program material. The DISTANCE SELECTOR switch determines the input level at which gain reduction (Level-Lot action) begins. An INPUT LEVEL CONTROL is also provided that:

Can be used as a vernier control to allow fine adjustment of input threshold between the preset threshold levels selected by the DISTANCE SELECTOR switch.

2. Can act as an input attenuator for signals that are higher than normal microphone levels. Such inputs may be: signals from microphones used very close to the mouth, outputs from preamplifiers, line amplifiers, tuners or tape recorders.

The Audio Level Controller: –

n Reduces blasting or large volume increases

when a speaker or entertainer varies his distance and position from the microphone.

n Upgrades tape-recording systems and the Audio

portion of Video Tape Recorders, by controlling the maximum signal level being fed to the recorder. This prevents distortion and overloading of the tape recorder which might be caused by “close talking” the microphone, or by very loud vocal or musical passages.

n Permits any number of microphones to be used

in a paging system or conference arrangement, without setting the level for each individual microphone. (For paging systems only low impedance microphones with normally open switches should be used.) Any number of these microphones may be operated in parallel across the low impedance input of the M62V, the Audio Level Controller will automatically set a fixed maximum paging level that cannot be exceeded.

SPECIFICATIONS

Input Impedance (below threshold):

High Impedance: 50 K ohms Low Impedance: 300 ohms (for 25 to 600 ohm

Input Levels:

High Impedance: microphone level to 10 volts Low Impedance: microphone level to .2 volt

Output Impedance:

High Impedance Microphone Level: 3.3 K ohms

Minimum recommended load: 5 K ohms

Low Impedance Microphone Level: Less than 50

ohms Minimum recommended load: 25 ohms

Aux. Output: 10 K ohms.

Minimum recommended load: 10 K ohms

Gain Characteristics: [Below threshold, Input Level

control Maximum (10); measured from input to output] :

INPUT

Hi Imp. Mic. Unity

Lo Imp. Mic.

Frequency Response:

± 2 db 40 to 20,000 Hz

sources)

max. (using input level control) max. (using input level control)

OUTPUT

Hi Imp. Mic. Lo Imp. Mic. Aux. Output

+20 db

-20 db Unity

+60 db

+80 db

27A823 (JI)

Printed in U.S.A.

Maximum Output Noise (high-impedance microphone

output), in db below 1 volt:

300-20,000 Hz

(Noise)

30-20,000 Hz

(Hum and Noise)

Lo Imp. input 150 ohm Termination -103 db

-95 db

Hi Imp. Input 33 K ohm Termination -104 db

-95 db

Distortion (any level of regulation):

3% maximum THD.

Dynamic Characteristics:

Fast attack, moderate re-

covery, fixed. Attack: For a 20 db step increase above threshold,

gain is within 2 db of final value in 500 microseconds.

Recovery: For a 20 db step decrease to threshold,

gain is within 2 db of final value in 700 milliseconds.

Battery Life: Approximately 200 hours. Dimensions: See Figure 5. Net Weight: 2.2 Ibs.

switch above the receptacle. This output is designed to work into a 25 to 600 ohm microphone line or microphone input, or into a high impedance amplifier or tape recorder microphone input. The receptacle

is a male three-pin Cannon type XL-3-14 connector (uses XL-3-11 mate, Shure Part No. 95A38, or XL-3-11 C mate, Shure Part No. 95A176). See Figure 2b for microphone level output receptacle connections.

MICROPHONE OUTPUT PLUG CONNECTIONS

FIGURE 2b

The receptacle marked AUX. OUTPUT is a phono

pin jack which accepts a standard phono pin plug.

This output is designed to work into a high-impedance

(10 K ohm or greater), high level input of a mixer, preamplifier, amplifier, or tape recorder. This output may be connected to the AUX. INPUT of an M68 Series Mixer, the HIGH-LEVEL INPUT of an M63 Audio Master or the line input (bridging) of an M67 Professional

Microphone Mixer.

The static characteristics of the high-level AUX. OUTPUT are shown in Figure 1b. This output provides a constant 1 volt level (with a 47 K ohm load) whenever the input level is above threshold. Below threshold it provides approximately 60 db of gain over the

Hi-Imp Mic. Level Input.

NOTE: This output is disabled when the MASTER

CONTROL switch is set to “Bypass.”

Input Connections: The Cannon-type receptacle

marked INPUT is designed for either low (25 to 600 ohms) or high impedance (50,000 ohms) inputs. The impedance is selected by a slide switch above the

input receptacle. The unit is not recommended for use

with crystal or ceramic microphones.

The input receptacle is a female Cannon-type XL-3-13 (uses XL-3-12 mate, Shure Part No. 95A55, or XL-3-12C mate, Shure Part No. 95A227). See Figure

2a for low and high impedance connections to receptacle.

INPUT PLUG CONNECTIONS

FIGURE 2a

Output Connections: The receptacle marked MIC.

OUTPUT is a dual impedance output selected by the

Battery and Auxiliary Power Connections:

The battery to power the M62V is shipped with the

unit but must be installed. Install as follows:

1. Remove Battery Compartment Cover by removing the lower slotted screw holding cover, loosening the upper screw, and sliding the cover down.

2. Snap battery into clips provided.

3. Replace Battery Compartment Cover and tighten screws securely.

Battery Replacement-Use Eveready type 216 or 222, or equivalent 9 V. Battery.

AUX. INPUT POWER: This jack is used as a power input when using the power supply of a Shure M67 or

M68 Series Mixer or M63 Audio Master.

case, the battery should be disconnected. A special

connecting cable is provided to connect the AUX. INPUT POWER jack on the M62V to the Accessory 28 V. D.C. jack on the M68 Mixer or to the Pos. (red) 30 V. D.C. jack on the M67 Mixer or M63 Audio Master.

In order to utilize A.C. current, the use of a 9 volt

D.C. Battery Eliminator is suggested. There is a pro-

vision in the battery compartment cover that will allow

using a 9 V. D.C. Battery Eliminator to power the M62V. The Battery Eliminator cable is to be slipped into the split rubber grommet on the cover of the battery com-

partment. To secure cable, rotate grommet ½ turn.

Connection is to be made using the same battery clips that normally connect to the 9 volt battery.

(Note: If a Shure M68, M67 or M63, or a Battery

Eliminator is to be used, first remove the battery.)

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