Shure LMP1A User Guide

GENERAL

MIC LO

–PWR

MIC LO

+PWR

MIC HI

GND

OUTPUT

INPUT

TO RADIO MIC
IN

FROM DYNAMIC MIC

AUDIO IN

GND

GND

EXT DC BIAS

AUDIO OUT

MIC HI

WHITE

GREEN

SHIELD

GND

OUTPUT

INPUT

12 VDC POWER SUPPLY

FROM DYNAMIC MIC

EXT DC BIAS

AUDIO OUT

TO RADIO MIC
IN

AUDIO IN

GND

GND

WHITE

GREEN

SHIELD

The Shure Model LMP1A is a multi-purpose level-matching
preamplifier designed for two-way radio communication applica­tions. The LMP1A allows Shure dynamic communication micro­phones to be used with many popular two-way radios and remote
control devices.

The LMP1A can operate on biased audio supplied by the radio or 12 Vdc provided by an external power supply. Its output can be adjusted to match the inputs of many two-way radios.

Model LMP1A User Guide

CONNECTING THE LMP1A TO NON-BIASED AUDIO RADIOS

1. Remove the screws that secure the LMP1A cover to the chas­sis and lift the cover away.

2. Refer to Figure 2 and connect a dynamic micorphone, such as a Shure Model 515, to the LMP1A input terminal as follows:

• White mic lead to LMP1A Audio In

• Green mic lead to LMP1A Ground

• Shield to LMP1A Ground

3. Connect the LMP1A output terminal to the radio input as follows:

• LMP1A Audio Out to Radio Microphone High Input

• LMP1A Ground to Radio Microphone Low Input or Ground

4. Connect the LMP1A external dc bias terminal to the positive terminal of the radio power supply.

5. Connect the LMP1A ground terminal to the negative terminal of the radio power supply.

6. Reinstall the LMP1A top cover.

FEATURES:

• Compact design

• Input and output terminals for easy connection to micro-

phones and radios

• Adjustable gain

• Uses either biased audio or external 12 Vdc power

• Heavy duty die cast aluminum case

INSTALLATION

CONNECTING THE LMP1A TO BIASED AUDIO RADIOS

1. Remove the screws that secure the LMP1A cover to the chas­sis and lift the cover away.

2. Refer to Figure 1 and connect a dynamic microphone, such as a Shure Model 515, to LMP1A input terminals as follows:

• White mic lead to LMP1A Audio In

• Green mic Lead to LMP1A Ground

• Shield to LMP1A Ground

3. Connect LMP1A output terminals to the radio input as follows:

• LMP1A Audio Out to Radio Mic High Input

• LMP1A Ground to Radio Microphone Low Input or Ground.

4. Reinstall the LMP1A top cover.

LMP1A CONNECTIONS FOR BIASED AUDIO RADIOS

FIGURE 1

LMP1A CONNECTIONS FOR NON-BIASED AUDIO RADIOS

FIGURE 2

©2003 Shure Incorporated
27D3050 (Rev. 4)

Printed in U.S.A.

LMP1A GAIN ADJUSTMENT

1. Remove the screws that secure the LMP1A cover to the chassis and lift the cover away.

2. Refer to Figure 3. Using a screwdriver, rotate potentiometer
R5 clockwise to increase gain. The LMP1A provides 20 dB of
gain when potentiometer R5 is in the maximum (full clockwise)
position. To decrease gain, rotate potentiometer R5 counter­clockwise.

ADJUSTING LMP1A GAIN

FIGURE 3

SPECIFICATIONS

Open Circuitry Gain

20 dB at 1 kHz, with potentiometer R5 set to maximum

Power Requirements

3.5 to 20 Vdc (Bias voltage supplied by radio);
12 Vdc provided by external power supply

Current Drain

0.7 mA at 12 Vdc

Case

Die-cast aluminum construction

Dimensions

63.75 mm x 57.66 mm x 35.05 mm (2.51 in. x 2.27 in. x 1.38 in.)

Net Weight

146 grams (5.15 oz)

Certification

Eligible to bear CE Marking. Conforms to European EMC Direc­tive 89/336/EEC. Meets applicable tests and performance cri­teria in European Standard EN55103 (1996) parts 1 and 2, for
residential (E1) and light industrial (E2) environments.

FROM MICROPHONE TO RADIOS

LMP1A SCHEMATIC DIAGRAM

FIGURE 4

SHURE Incorporated Web Address: http://www.shure.com
5800 W. Touhy Avenue, Niles, IL 60714-4608, U.S.A.
Phone: [phone] Fax: [phone]
In Europe, Phone: [phone] Fax: [phone]
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Elsewhere, Phone: [phone] Fax: [phone]

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