.

that no multiple ground circuits are formed

when the microphones are mounted on tripods etc.

Connection to Amplifiers with High Input Sensitivity

If the amplifier being used has a very high input sensitivity, i. e. when it is normally intended 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

I"e amplifie!', whi~h helps to increase the ~~nal to nOlse ratio.

Connection to Amplifiers with Defined Input Impedances

Sennheiser 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. How-

ever, if the input impedance is 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. Tho

voltage division caused by this se des resistor must of course be considered.

The same method can be used when a higher output impedance of the microphono is demanded. In this case again asories 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 :t 2 volt. It should be so stabi-

lised and filtered, that the unweighted noise voltage is less than 5 flV and that the weighted noise components are less than 2 ~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 :t 1 %. This

means that approx. 2 volts are lost across the resistors.

The circuit of the MKH 415 is so dimen-

sioned that a supply voltage tolerance of 12 volts :t 2 volts is permitted.

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