Shure 550L User Guide

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Model 550L User Guide

TRANSMIT

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BLACK

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GENERAL

The Shure 550L is an omnidirectional dynamic base station
microphone with a frequency response specially tailored for
voice intelligibility. It is equally useful for radio
communications, paging and dispatching systems, and its
low-impedance connection makes it adaptable to most PA
amplifiers. The low-impedance design also makes it useful
for long runs of cable, or under severe hum disturbance
conditions.
The microphone is not affected by heat or humidity. Its

exclusive ARMO-DUR

®

case is immune to oil, grease,
fumes, salt spray, sun, rust, and corrosion–and is
outstanding in its ability to resist mechanical shocks and
vibration. The “Million-Cycle” leaf-type switch is designed to
withstand rigorous operating conditions and constant use.

Features

• Low-impedance operation

• Crisp, natural, high-intelligibility voice response

• Fingertip control bar actuates microphone circuit and exter-

nal relay or control circuit

• Long-life switch meets rigorous requirements of communi-

cations and paging systems

• Sturdy, high-impact ARMO-DUR base and microphone

case resists corrosion

• Reliability under all operating conditions

• Neoprene feet prevent microphone slipping

PRESS-TO-TALK SWITCH OPERATION

The fingertip control bar is a non-locking switch; simply
depress the control bar and release after transmission.

WIRING

Figure 1 shows the internal wiring of the 550L microphone.

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INTERNAL CONNECTIONS

FIGURE 1

GREEN

SHIELD

The 550L may be wired for balanced or unbalanced
operation. For unbalanced operation, the green cable wire
is connected to the audio input, the white cable wire is
connected to the audio ground, and the shield is connected
to the chassis ground. See Table 1.

For balanced operation, the green cable wire is connected
to the audio input positive (+), the white wire is connected to
the audio negative (-), and the shield is connected to the
chassis ground. See Table 1.

Table 1. Cable-to-Connector Wiring

INPUT TYPE

UNBALANCED WHITE AUDIO GROUND PIN 3 SLEEVE

BALANCED WHITE AUDIO - PIN 3 RING

NOTE: The red and black wires are not part of the audio circuit.
These wires provide a contact closure when the microphone
switch is depressed. This closure may be used to control an exter­nal relay or transmit/receive circuit.

WIRE

COLOR

GREEN AUDIO PIN 2 TIP

SHIELD CHASSIS GROUND PIN 1 SLEEVE

GREEN AUDIO + PIN 2 TIP

SHIELD CHASSIS GROUND PIN 1 SLEEVE

FUNCTION XLR

CONNECTOR

1/4 IN. PHONE

PLUG

IMPEDANCE MATCHING

Low-impedance operation is extremely useful where long
cable lengths are required, or under conditions of severe
hum disturbance. The permissible cable length is practically
unlimited, since neither response nor level is appreciably
affected. Shure A95 Series Line Matching Transformers are
available for use in those cases where a low-impedance
microphone is to be used with an amplifier with a
high-impedance input. These transformers provide a proper
impedance match between a 19- to 300-ohm microphone
and a high-impedance input, and are available with various
input and output connectors.

©2005, Shure Incorporated

27C8090 (Rev. 4)

Printed in U.S.A.

SPECIFICATIONS

57 mm

(2-1/4 IN.)

57 mm

(2-1/4 IN.)

12.7 mm
(1/2 IN.)
TRAVEL

4.8 mm

(3/16 IN.)

264 mm

(10-3/8 IN.)

2.8 mm

(7/64 IN.)

28.6 mm

(1-1/8 IN.)

149 mm

(5-7/8 IN.)

66.7 mm
(2-5/8 IN.)

44.4 mm

(1-3/4 IN.)

Type

Dynamic

Frequency Response

150 to 6,000 Hz (see Figure 2)

+10

0

dB

–10

Dimensions

See Figure 3

20 200001000 1000050 100

98765432

Hz

98765432

TYPICAL FREQUENCY RESPONSE

FIGURE 2

Polar Pattern

Omnidirectional

Impedance (at 1,000 Hz)

Microphone rating impedance is 150 ohms (220 ohms ac­tual) for connection to microphone inputs rated at 75 to
300 ohms

Output Level (at 1,000 Hz)

Open Circuit Voltage* . . . . . . . . . .-54.0 dB/Pa (2.0mV)

*(1 Pa = 94 dB SPL)

Switch

Press-to-Talk Switch actuates microphone circuit and ex­ternal relay or control circuit. Microphone circuit normally
open.

Cable

2.1m (7 ft) four-conductor, two-conductor shielded,
non-detachable

Case

Brown ARMO-DUR

®

with dull chrome-plated steel

screen

OVERALL DIMENSIONS

FIGURE 3

Net Weight

836 grams (1 lb, 13-1/2 oz)

Shipping Weight

1.12 kilograms (2 lb, 7-1/2 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.

REPLACEMENT PARTS

Cartridge .................................................................... R96

Cable....................................................................... C32C

Switch.................................................................. RK321S

For additional service or parts information, please contact
the Shure Service Department at 1-800-516-2525. Outside
the United States, please contact your authorized Shure
Service Center.

SHURE Incorporated http://www.shure.com
United States, Canada, Latin America, Caribbean:
5800 W. Touhy Avenue, Niles, IL 60714-4608, U.S.A.
Phone: [phone] U.S. Fax: [phone] Intl Fax: [phone]
Europe, Middle East, Africa:
Shure Europe GmbH, Phone: [phone] Fax: [phone]
Asia, Pacific:
Shure Asia Limited, Phone: [phone] Fax: [phone]