639a
Common name: Western Electric 639a
Production Status: Discontinued / Vintage
The Western Electric 639a microphone uses the classic combination of dynamic pressure element and pressure-gradient ribbon to produce a cardioid pattern. The 639a can be switched between omni, cardioid and figure-of-eight while the 639b has six patterns and additionally allows hypercardioid pickup. The microphone is also found under the Altec label and forms the basis for the later STC4033 design. In this guise it was widely used by the BBC both as a stand microphone and on racked booms.
(639a image – all rights reserved ©1996-2004 James Steele)
Electrical Characteristics
Frequency Response
40Hz - 10 kHz
Output Sensitivity
0.6 mV/Pa
Max SPL
Max SPL, THD:
Self Noise (CCIR)
dB
Self Noise (DIN/IEC)
16 dB-A
Output Impedance
40Ω
Recommended Load
Powering
Supply Current
mA
Alternative Powering
Switchable Options
Pad
Filter/EQ
Physical Characteristics
Connector
442A jack
Connector notes
1&3 signal, 2 ground
Available Colours
Weight
1500 g
Length
190 mm
Min diameter width
Max diameter
90 mm
Depth
115mm
Accessories
Included
Optional