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-
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.
BLACK
WHITE
RED
BLACK
WHITE
GREEN
SHIELD
TRANSMIT
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
COLOR FUNCTION XLR CONNECTOR 1/4 IN. PHONE
PLUG
GREEN AUDIO PIN 2 TIP
UNBALANCED WHITE AUDIO GROUND PIN 3 SLEEVE
SHIELD CHASSIS GROUND PIN 1 SLEEVE
GREEN AUDIO + PIN 2 TIP
BALANCED WHITE AUDIO – PIN 3 RING
SHIELD CHASSIS GROUND PIN 1 SLEEVE
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.
Model 550L User Guide
27B8090 (TL)
2000, Shure Incorporated Printed in Mexico

SPECIFICATIONS
Type
Dynamic
Frequency Response
150 to 6,000 Hz (see Figure 2)
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20 200001000 1000050 100 98765432 98765432
+10
0
–10
Hz
dB
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
Dimensions
See Figure 3
ÎÎÎ
ÎÎÎ
ÎÎÎ
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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.)
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
Conforms to European Union directives, eligible to
bear CE marking; meets European Union EMC Immu-
nity Requirements (EN 50082–1, 1992).
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. Out-
side the United States, please contact your authorized
Shure Service Center.
SHURE Incorporated Web Address: http://www.shure.com
222 Hartrey Avenue, Evanston, IL 60202–3696, U.S.A.
Phone: [phone] Fax: [phone]
In Europe, Phone: [phone] Fax: [phone]
In Asia, Phone: [phone] Fax: [phone]
Elsewhere, Phone: [phone] Fax: [phone]