Specification Sheet
MODEL BETA 87C CONDENSER MICROPHONE
2
Output Impedance
Rated at 150 ohms (100 ohms actual ±20%)
Recommended minimum load impedance: 800 ohms
Sensitivity (at 1,000 Hz)
Open Circuit Voltage –51 dBV/Pa (2 mV). . . . . . . . . . . . . . . .
(1 Pa = 94 dB SPL)
Output Clipping Level
1000 ohm Load
at 1,000 Hz –6 dBV (0.5 V). . . . . . . . . . . . . .
Maximum SPL
139 dB
at 1,000 Hz (0.25% THD, 1000 ohm load)
Self-Noise
22 dB typical, A-weighted
24 dB typical, weighted per DIN 45 405
(equivalent sound pressure level; measured with true rms voltme-
ter)
Dynamic Range
117 dB (maximum SPL to A-weighted noise level)
Hum Sensitivity
–5 dB equivalent SPL, maximum, in a 1 mOe field (60 Hz)
Signal-to-Noise Ratio
72 dB at 94 dB SPL (IEC 651)*
*S/N ratio is difference between 94 dB SPL and equivalent SPL of self–noise
A-weighted.
Polarity
Positive pressure on diaphragm produces positive voltage on
pin 2 relative to pin 3 of the output connector. See Figure 4.
BETA 87C BLOCK DIAGRAM
Power
Phantom Supply Requirement 11 to 52 Vdc, positive . . . . .
at both pins 2 and 3
Current Drain 1.0 to 1.2 mA. . . . . . . . . . . . . . . . . . . . . . . . . . .
Connector
Three–pin (XLR) professional audio
Case
Aluminum construction with painted blue metallic finish, and
hardened steel grille with nickel satin chrome plating
Dimensions
See Figure 5
21 mm
(
53
/
64
in.)
51 mm
(2 in.)
192 mm
(7–
9
/
16
in.)
OVERALL DIMENSIONS
Net Weight
Net: 207 grams (7.6 oz)
Packaged: 565 grams (1.24 lbs)
Environmental Conditions
Operating: –18
° to 60° C (0° to 135° F)(relative humidity <90%)
Storage: –29
° to 74° C (–20° to 165° F) (relative humidity <80%)
FURNISHED ACCESSORIES
Swivel Adapter A25D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Carrying/Storage Bag 26A13. . . . . . . . . . . . . . . . . . . . . . .
REPLACEMENT PARTS
Grille RK312. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Replacement Amplifier Assembly 90KF2600. . . . . . . . .
OPTIONAL ACCESSORIES
Phantom Power Supply PS1A. . . . . . . . . . . . . . . . . . . . . .
Isolation Mount A53M, A53HM. . . . . . . . . . . . . . . . . . . . .
Windscreen A85WS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.6 m (25 ft.) Cable C25F. . . . . . . . . . . . . . . . . . . . . . . . . .
