Shure 550L User Manual

GENERAL
The Shure 550L is an omnidirectional dynamic base sta-
tion microphone with a frequency response specially tai-
lored for voice intelligibility. It is equally useful for radio com-
munications, 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 con-
ditions.
The microphone is not affected by heat or humidity. Its ex-
R
clusive 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 "Mil-
lion-Cycle" leaf-type switch is designed to withstand rigor-
ous operating conditions and constant use.
Features
Low-impedance operation
Crisp, natural, high-intelligibility voice response
Fingertip control bar actuates microphone circuit and
external relay or control circuit
Long-life switch meets rigorous requirements of com-
munications 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 de-
press the control bar and release after transmission.
WIRING
Figure 1 shows the internal wiring of the 550L microphone.
2000, Shure Incorporated
27B8090 (TL)
Model 550L User Guide
BLACK
WHITE
INTERNAL CONNECTIONS
FIGURE 1
The 550L may be wired for balanced or unbalanced op-
eration. For unbalanced operation, the green cable wire is
connected to the audio input, the white cable wire is con-
nected 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 WIRE FUNCTION
COLOR
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 cir-
cuit. These wires provide a contact closure when the micro-
phone switch is depressed. This closure may be used to
control an external 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 af-
fected. Shure A95 Series Line Matching Transformers are
available for use in those cases where a low-impedance mi-
crophone is to be used with an amplifier with a high-imped-
ance input. These transformers provide a proper impedance
match between a 19- to 300-ohm microphone and a high-im-
pedance input, and are available with various input and out-
put connectors.
TRANSMIT
BLACK
WHITE
GREEN
SHIELD
XLR
CONNECTOR PHONE
AUDIO PIN 2
PIN 3 SLEEVE
PIN 1 SLEEVE
AUDIO + PIN 2
AUDIO – PIN 3
PIN 1 SLEEVE
Printed in Mexico
RED
1/4 IN.
PLUG
TIP
TIP
RING