LAVALIERCONDENSERMICROPHONE
MKH 124,MKH125 T, MKH 126 P48
Introduction
The microphone part MK 12 is a Lavalier condenser microphone in RF-
technique leaturing adiaphragm 01only 6 mm diameter. Corresponding
to its use the microphone was designed as pressure transducer (omni-
directional). Therelore, the MK 12 is very insensitive to handling noises.
The complete microphone consists 01two parts, the miniature micro-
phone and the electronic unit. MH 124, MH 125 T, MH 126 P48 or the
studio transmitter SK 1007 may be alternatively connected to the MK 12.
The prolongation between microphone and electronic unit is possible
with connection cable MZV 125.
Technical Notes
High Frequency Circuit
The capsule 01a RF condenser microphone presents, contrary to low
Irequency circuits, a low impedance output. Instead 01the high pola-
rization voltage normally required, ahigh Irequency capsule needs only a
high Irequency voltage 01about 10 volts, which is produced by a built-in
low noise oscillator (8 MHz). The low capsule impedance leads to a high
performance reliability 01the microphones.
MK12+ MH124= MKH124
The MKH 124 is designed lor direct connection to the Microport-
transmitter SK 1008-3. The power supply is provided by the transmitter.
MK12+ MH125T = MKH125T
The MKH 125 T is designed lor AB-powering.
Sennheiser electronic introduced A-B powering, which was then
standardisedin DIN 45595. Aswith dynamic microphones, only two wires
are required to connect the microphone when this powering system is
being used. The operating current isled along the same wires asthe
audio Irequency signal, so that the circuitry in the microphone does not
have to be connected to ground. Because 01these ground-Iree tech-
niques the highest possible values 01immunity lrom noise ordisturbance
are achieved.
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