1=
that when the microphones are mounted on
tripods etc. no multiple earth circuits are
formed.
Connection to amplifiers with high input
sensitivity
If the amplifier being used has a very high
input sensitivity, i. e. when it is normally in-
tended for use with dynamic microphones,
it can be necessary to reduce the output
voltage from the microphone by means of
a voltage divider. This should be built into
the microphone cable at the amplifier input.
By this means the large signal on the micro-
phone cable is maintained up to just before
the amplifier, which helps to increase the
signal to noise ratio.
Connection to amplifiers with defined input
impedances
Senn heiser studio condenser
microphones
can be connected direct to all amplifiers
whose input impedance is larger than 200 Q.
This is usual in the majority of cases. Should,
however, the input impedance be smaller
than 200 Q, a resistor of appropriate value
should be placed in series with the micro-
phone so that it "sees" at least 200 Q. The
voltage division caused by this series re-
sistor must of course be considered.
The same method can be used when a
higher output impedance of the microphone
is demanded. In this case again, aseries
resistor can be used
to provide correct
matching.
Connection to amplifiers with powering
facilities
If an appropriate voltage source is available
in the amplifier the condenser microphone
can be
powered direct. The voltage should
be 12 volts::!:: 2 volt. It should be so stabi-
lised and filtered, that the
unweighted noise
voltage is less than 5
I-lV and that the
weighted noise components are less than
2 I-lVolts. The
current consumption of the
microphone is approximately 5 to 6 mA.
According to the DIN standard the feed
resistors should be 2 x 180 Q ::!:: 1 %. This
means that approx. 2 volts are lost across
the resistors.
The circuit of the MKH 435 is so dimen-
sioned that a supply voltage tolerance of
12 volts::!:: 2 volts is permitted.
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