MODEL SM98
UNIDIRECTIONAL CONDENSER MICROPHONE
GENERAL
The SM98 is a miniature electret condenser microphone
with a unidirectional (cardioid) pickup pattern. A smooth
wide frequency response from 40 to 20,000 Hz allows the
microphone to be extremely well adapted to pick up all
kinds of musical instruments. A detachable 4.6m (15 ft)
cable with Switchcraft Tini Q.G. connectors and a battery
or simplex (phantom) powered preamplifier are supplied
with the microphone. A windscreen is provided for outdoor use, and a swivel adapter is supplied for conventional
microphone stand or goose neck mounting.
The unidirectional pattern of the SM98 discriminates
against sounds coming from the rear, permitting higher
gain before feedback in sound reinforcement applications. Because of its uniform cardioid pattern extending
out to 20,000 Hz, the microphone can be used for pickup of
a particular instrument in an ensemble or orchestra, minimizing the need for isolation booths or barriers. A very
high maximum sound pressure level allows use of the
SM98 with all acoustic instruments including drum kits
and other percussion as well as brass, reed, wind, string,
and keyboard instruments. The SM98 can also be used
with amplified guitars and keyboards.
The low-distortion, high-clipping-level preamplifier
provides switch-selectable Flat or Low-Cut response to
suit pickup characteristics needed for various instruments. The Low-Cut position is also useful when it is
necessary to filter out low-frequency noise from such
sources as wind noise or air conditioning equipment.
The SM98 is powered either by two readily available
9-volt alkaline batteries (300 hours continuous battery
life) or by an 11-to-52 Vdc simplex (phantom) supply from
sound reinforcement, recording or broadcast equipment.
The preamp is designed so that the battery supply will
automatically switch in should the simplex power fail.
However, no battery drain will occur as long as the simplex
voltage exceeds the battery voltage.
A series of optional accessories is available designed
exclusively for use with the SM98. These include the following: A98MK Drum Kit, a gooseneck holder for mounting the microphone directly on most drums; A98-G18, an
18-inch gooseneck for mounting the microphone on a
podium, table, or desk; A98HA, a hanging adapter permitting the microphone to be suspended from above; and
A98PF, a pop filter and locking collar kit, allowing the
SM98 to be used for speech or vocal pickup.
Features:
•
Smooth wide response for accurate sound reproduction across the entire audio spectrum
•
Symmetrical cardioid pattern, uniform with frequency
out to 20 kHz, maximizes gain before feedback, minimizes need for isolation when picking up single instruments out of a group
•
Switch-selectable 12 dB/octave low-frequency cutoff
permits tailoring response to suit particular instruments or room conditions
•
Very high SPL capability
•
Very low distortion and high output clipping level
•
Battery or simplex (phantom) powering: uses standard
9-volt alkaline batteries; accepts wide range of simplex
voltages, from 11 to 52 Vdc
•
Low susceptibility to RFI, electrostatic and electromagnetic hum
•
Rugged construction of microphone and preamplifier
for outstanding reliability
•
Detachable cable at both microphone and preamplifier
•
Usable over very wide range of temperature and
humidity
Supplied with unique swivel adapter for mounting on
•
conventional microphone stands or goosenecks
Optional accessories to increase microphone’s versa-
•
tility include: A98MK, Drum Kit; A98-G18, Gooseneck
Adapter; A98HA, Hanging Adapter; A98PF, Pop Filter
SPECIFICATIONS:
Type
Cardioid condenser (electret bias)
Frequency Response
40 to 20,000 Hz (see Figure 1)
222 HARTREY AVENUE, EVANSTON, ILLINOIS 60202-3696 U.S.A. • PHONE (312) 866-2200 • TELEX 4330191 • FAX (312) 866-2279
Copyright 1987, Shure Brothers Inc.
27A2173(GJ)
Printed in U.S.A.
Polar Pattern
Unidirectional (cardioid), uniform with frequency,
symmetrical about axis (see Figure 2)
TYPICAL POLAR PATTERN
FIGURE
Output Impedance
Rated at 150 ohms (90 ohms actual)
Recommended minimum load impedance: 800 ohms
(May be used with loads as low as 150 ohms with
reduced clipping level)
Output Level (at 1,000 Hz)
Open Circuit Voltage . . . . . . . . . . . . . -80.0 dB (0.10 mV)
0 dB = 1V/µbar
2
Battery On/Off Switch: Move to On to power from batteries or to use batteries as backup power in case of
interruption to external power supply (no battery drain
occurs as long as simplex voltage source is greater than
battery voltage). Move to Off to prevent battery drain
when unit is not in use
LED Indicator: Green LED flashes momentarily when
switch is moved to On to indicate at least 8 hours of
battery life remaining
Flat/Lo Cut Switch: In Lo Cut position, 12 dB/octave
rolloff below 80 Hz (see Figure 1)
Cable
4.6m (15 ft) two-conductor shielded, small diameter,
interconnecting cable with 3-socket miniature Switchcraft Tini Q.G. connector on each end to mate with
microphone output connector and preamplifier input
connector
Case
Microphone: Matte black enamel brass case and stainless steel inner grille
Preamplifier: Matte black enamel die-casting
Dimensions
See Figure 3
Preamplifier Output Clipping Level (at 1,000 Hz, less than
0.1% THD)
800 ohm load . . . . . . . . . . . . . . . . . . . . . . . . .
150 ohm load
Maximum SPL (at 1,000 Hz)
800 ohm load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
150 ohm load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hum Pickup
-5 dB equivalent SPL in 1 m0e field (60 Hz)
Output Noise
34 dB SPL, A-weighted
37 dB SPL, weighted per DIN 45 405
Signal-to-Noise Ratio
64 dB re 94 dB SPL
Dynamic Range
121 dB
Phasing
Positive pressure on diaphragm produces positive
voltage on pin 2 relative to pin 3 of preamplifier output
connector
Power
Battery: Two 9-Vdc alkaline (NEMA 1604A), approximately 300 hours continuous with fresh alkaline
batteries
Simplex (Phantom) Voltage: 11 to 52 Vdc, operational
down to 9 Vdc; 1.8 mA current drain; permissible to use
simplex power with batteries in place or removed
Switches and indicator
Two recessed slide switches and green LED indicator
on top surface of preamplifier assembly
. . . . . . . . . . . . . . . . . . . . . .
0 dBV (1.0V)
-13 dBV (0.22V)
155 dB
145 dB
OVERALL DIMENSIONS
FIGURE 3
Environmental Conditions
Operating Temperature:
Storage Temperature: -29° to 74° C (-20° to 168° F)
Relative Humidity (Operating or Storage): 0 to 95%
Net Weight
Microphone: 12 grams (0.4 oz) less cable
Preamplifier: 435 grams (15.4 oz) less batteries
Furnished Accessories
Windscreen, Swivel Adapter
USING THE SWIVEL ADAPTER
To mount the SM98 in the supplied swivel adapter:
1. Mount the adapter on a microphone stand.
2. Loosen the thumbscrew at the top of the adapter.
3. Attach the microphone to the connector.
4. Slip the cable through the slot in the adapter. Slide the
connector back through the hole until the protruding
black cable-lock button is in the open slot and the
microphone stops flush with the flat on the adapter.
-18° to 57° C (0° to 135° F)
2
SWIVEL ADAPTER
FIGURE 4
Making sure the thumbscrew will clamp on the silver
metal segment of the connector, NOT ON THE BLACK
PLASTIC PART, tighten the thumbscrew.
CAUTION: Tightening the thumbscrew on the plastic
section of the connector could damage the connector
body.
Tilt the adapter to aim the microphone as desired.
To remove the microphone without disturbing the
swivel adapter and cable, reach into the open slot of the
adapter and press the cable-lock button while disengaging the microphone.
POWERING THE SM98
The SM98 can be powered by two internal 9-volt alkaline
batteries or by an external simplex supply of 11 to 52 volts
dc.
To use batteries, move the Battery On/Off switch to On.
The green LED will indicate at least 8 hours of battery life
remaining by flashing once when the switch is moved to
On. If the LED does not flash, the batteries should be
replaced. A battery-powered SM98 preamplifier output
can be connected to any balanced-line low-impedance
input.
To use simplex power, connect the preamplifier output
to a balanced-line microphone input supplying 11 to 52
Vdc simplex (phantom) power. The batteries may be left in
place while the unit is externally powered. There will be no
battery drain as long as the simplex voltage exceeds the
battery voltage with the battery switch On, or if the battery
switch is turned off.
OPTIONAL ACCESSORIES
Drum Mounting Kit. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gooseneck Adapter . . . . . . . . . . . . . . . . . . . . . A98-G18
Hanging Adapter
Pop Filter and Locking Collar. . . . . . . . . . . . . . . . A98PF
GUARANTEE
This Shure product is guaranteed in normal use to be
free from electrical and mechanical defects for a period of
one year from date of purchase. Please retain proof of
purchase date. This guarantee includes all parts and labor.
This guarantee is in lieu of any and all other guarantees or
warranties, express or implied, and there shall be no recov-
ery for any consequential or incidental damages.
. . . . . . . . . . . . . . . . . . . . . . . . . . A98HA
A98MK
BATTERY INSTALLATION
To install batteries, remove the two screws in the bottom
corners of the preamplifier case. Lift off the case cover
exposing the battery compartment. The use of 9-volt alkaline batteries (NEMA 1604A or equivalent) is highly
recommended. Two batteries are required; always replace
batteries in pairs.
To prevent possible damage due to leakage, remove the
batteries if the unit will not be used for a long period of
time.
INTERCONNECTING CABLE
One 4.6m (15 ft) cable is supplied for connecting the
SM98 Microphone to its preamplifier. To retain access to
the switches located on the preamplifier, it is sometimes
desirable for the units to be located a greater distance
apart. Up to 15m (50 ft) of additional cable can be used
between the SM98 Microphone and preamp with no loss in
response or output.
SHIPPING INSTRUCTIONS
Carefully repack the unit, have it insured, and return it
prepaid to: Shure Brothers Incorporated
Attention: Service Department
222 Hartrey Avenue
Evanston, Illinois 60202-3696
If outside the United States, return the unit to your dealer
or Authorized Shure Service Center for repair. The unit
will be returned to you prepaid.
MICROPHONE CIRCUIT DIAGRAM
FIGURE 5
PREAMPLIFIER CIRCUIT DIAGRAM
REPLACEMENT PARTS LIST
FIGURE 6
PREAMPLIFIER PC BOARD
FIGURE 7
Reference
Designation Number
Al
A2
C102, 107, 108, 110
C103
C106
D101, 102, 103, 105, 106
D104
D107
L1, L2
MP2
MP3
P1
P2
Q101, 105
Q102, 103, 104 86A348
S101, 102 55A8031
T1
W1
Part
90A8216
R134
86S628R
86AE629
86W628R
86A415R
86A8405
86C429
80A253
RK245
49A66
95A8077
95A247
86A350
51A286
C107
Description
Printed Circuit Board Assembly
Microphone Cartridge-Housing
Capacitor, Electrolytic, 1 µF, 50 Wvdc
Capacitor, Electrolytic, 33 µF, 16 Wvdc
Capacitor, Electrolytic, 15 µF, 63 Wvdc
Diode, Computer, 75V, 0.4A
LED, Green
Diode, Current Regulator, 1.3 mA
Ferrite Bead Ring
Swivel Adapter
Windscreen
Connector, Receptacle, 3-pin Miniature
Connector, Receptacle, 3-pin
Transistor, NPN
Transistor, PNP
Slide Switch, SPDT
Transformer
Cable and Connector Assembly
Commercial
Alternate
None
None
None
Mallory VTL33S25
None
TI, GE 1N4148
None
Motorola, Teledyne
1N5300
Stackpole 57-0180
None
None
Switchcraft TB3M
Switchcraft D3M
Motorola, National
Semiconductor 2N5210
Motorola, National
Semiconductor 2N5087
None
None
None
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