The connection 01Senn heiser condenser microphones and dynamic microphones as weil is carried out using the principle 01voltage matching. The advantages 01this system are that neither impedance variations 01the microphone output nor 01the amplilier input exercise a noticeable influence on the total Irequency response. The source impedance 01the Sennheisercondenser microphone with A-B powering is so low (approx.

20 Q at 1000 Hz) that an amplilier input with an impedance 01at least 200 Q will be suitable.

Sennheiser condenser microphones produce relatively large output voltages, these can be up to 1 volt with maximum sound pressure levels. This has the advantage that even with long cables induced interference signals can be disregarded. Also the internal noise produced by the microphone does not contribute to the total noise level. The microphones are litted with high Irequency lilters, which ensure that no high Irequency signals lrom the microphone can affect the external circuitry, and also that the microphone itsell is protected Irom high Irequency disturbance. It is, therelore, notnecessary, even underthe most difficult conditions, totake special precautions such as double screening 01the cables or the provision 01 high Irequency Iilters.

Sennheiser condenser microphones are polarised according to DIN standard i. e. when apressure signal strikes the capsule lrom the Iront, Pin 1 01the DIN-connector (resp. pin 2 01the Gannon connector) goes positive with relerence to Pin 3. This should be considered when the amplilier input is being wired.

Connection to Amplifiers with balanced Inputs

In this case the microphone is simply connected to the input 01an amplilier via a battery adapter MZA 15 or the power supply MZN 16 T.

Connection to Amplifiers with unbalanced Inputs

In many cases, lor example most tape recorders, the input socket is unbalanced. In this case one side olthe b~lanced microphone output has to be earthed. Apart lrom cases where the microphone is being used lor prolessional studio purposes, this is not critical, asthe large output voltage 01the microphone combined with its low output impedance provides a large signal to noise ratio. Gare should be taken, however, that no multiple ground circuits are lormed when the microphones are mounted on tripods etc.

Connection to Amplifiers with High Input Sensitivity

In the amplilier being used has a very high input sensitivity, i. e. when it is normally intended lor use with dynamic microphones, it can be necessary to reduce the output voltage Irom the microphone by means 01a voltage divider. This should be built into the microphone cable at the amplilier input. By this means the large signal on the microphone cable is maintained up to just belore the amplilier, which helps to increase the signal to noise ratio.

Connection to Amplifiers with Defined Input Impedances

Sennheiser studio condenser microphones can be connected directly to all ampliliers whose input impedance is larger than 200 Q. This is usual in the majority 01cases. However, il the input impedance is smaller than 200 Q, a resistor 01appropriate value should be placed in series with the microphone so that it "sees" at least 200 Q. The voltage division caused by this series resistor must 01course be considered.

The same method can be used when a higher output impedance 01the microphone is demanded. In this case again aseries resistor can be used to provide correct matching.

Connection to Amplifiers with Powering Facilities

1Ian appropriate voltage source is available in the amplilier the condenser microphone can be powered directly. The voltage should be

12.volts :t 2 volts. It should be so stabilised and liltered, that the un-

weighted noise voltage is less than 5 f.lVand that the weighted noise components are less than 2 f.lV.The current consumption 01the microphone is approximately 6 mA. According to the DIN standard the leed resistors should be 2 x 180 Q. This means that approx. 2 volts are

lost acrossthe resistors.

 

 

 

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A-B powering unbalanced connection

 

MK 12 + MH 126 P48 = MKH 126 P48

 

The MKH 126 P 48 is designed lor phantom powering. All Sennheiser

 

microphones designated MKH . . . P 48 and P 48-U are 48 V phantom-

 

powered according to DIN 45596. Either condenser- or dynamic micro-

 

phones Irom Senn heiser electronic employ the principle 01voltage

 

matching. This "no load condition" has the advantage that neither

 

impedance variations 01the microphone output nor 01the amplilier input

 

have a noticeable inlluence on the total performance 01the system

 

(e. g. Irequency response). The source impedance 01 Senn heiser con-

 

denser microphones with phantom powering is extremely low (about

 

20 Q at 1000 Hz) so that the amplilier input impedance has only to be

 

at least 200 Q.

 

Senn heiser condenser microphones produce relatively large output

 

voltages exceeding 1 volt at maximum sound pressure levels. This has

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the advantage that even with long cables induced interference signals can
be disregarded. Also the internal noise produced by the microphone does

 

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not contribute to the total noise level. The microphones are litted with
RF lilters which ensure that no high Irequency signals lrom the micro-
phone can affect the external circuitry and that the microphone itsell is

 

protected Irom high Irequency disturbance. It is therelore not necessary,

 

even under the most difficult conditions, to take special precautions, such

 

as double screening 01the cables or the provision 01high Irequency lilters.

 

Senn heiser condenser microphones are polarised according to DIN

 

stahdard i. e. when apressure pulse strikes the capsule lrom the Iront,

 

Pin 1 01the DIN-connector (resp. pin 2 01the Gannon connector) goes

 

positive with relerence to Pin 3. This should be considered when the

 

amplilier input plug is being wired lor correct phasing.

Connection to Amplifiers with balanced Inputs Phantom-powered microphones are generally to be connected to balanced ground-Iree translarmer inputs.

12

13