BRUEL & KJAER 4111 - Microphone 4111 Description and Specifications

DESCRIPTION
The Condenser Microphone type 4111 is particularly designed for mea-
surement applications and has therefore a very high stability and com-
paratively small dimensions. It is built up of a cartridge directly con-
nected with a cathode follower tube, making it possible without any dif-
ficulty to use long cables between the microphone and the following
amplifier. The polarization, anode and filament voltages to the ca-
thode follower and cartridge are all taken from the amplifier, which
is why only Microphone Amplifier type 2601 and Frequency Analyzer
type 2105 or 2109 can be used.
Fig. 1.
Photo of Condenser Microphone type 4111.
All the above mentioned apparatus is proviC::.ed with a special built-in
rectifier, w hich delivers d. c. current for filament to the cathode fol-
lo wer in or der to retain a low hum level.
T he cartridge is mounted in the end of a tube (diameter 36 mm, length
9u mm), which also contains the cathode follower with componeq.ts.