Shure 550L User Manual

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.
2005, Shure Incorporated
©
27C8090 (Rev. 4)
Model 550L User Guide
BLACK
WHITE
INTERNAL CONNECTIONS
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
WIRE
COLOR
INPUT TYPE
GREEN
UNBALANCED WHITE AUDIO GROUND
SHIELD CHASSIS GROUND
GREEN
BALANCED WHITE
SHIELD CHASSIS GROUND
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 exter-
nal relay or transmit/receive circuit.
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.
TRANSMIT
BLACK
WHITE
GREEN
SHIELD
FIGURE 1
FUNCTION XLR 1/4 IN. PHONE
CONNECTOR
AUDIO PIN 2
PIN 3
PIN 1
AUDIO + PIN 2
AUDIO - PIN 3
PIN 1
Printed in U.S.A.
RED
PLUG
TIP
SLEEVE
SLEEVE
TIP
RING
SLEEVE