Buffer amplifier

A microphone amplifier is an internal component of condenser and electret microphones sitting in the signal flow locally directly behind the microphone capsule. Functionally this case no voltage is amplified, as the name suggests, it is carried out impedance conversion ( current gain ).

The diaphragm of a condenser microphone is a high-impedance voltage source, that does not provide enough power to send the signal distortion, directly via a cable to the console. Therefore, an impedance transformer is required; this is also referred to as a microphone amplifier. It is not (!) A voltage amplifier ( voltage gain = 1). Its task is only to adapt the signals of the high-impedance condenser capsule for transmission through the microphone cable and to the input of the mixer. There is an impedance transformation of the very high-impedance condenser capsule (> 1 GΩ ) to a much lower output impedance (<200 Ω in studio art).

Moreover, in the studio technology, a conversion takes place in a balanced signal, this may be a transformer or an electronic circuit can be used. The supply voltage for the impedance converter often comes from a delivered from the mixer phantom power that is predominantly 48V.

In the studio engineering exists only in exceptional cases, a voltage amplifier in the microphone. This also applies electret.

Something else is the mic preamp, mic preamp called English. Here the low voltage at the microphone output (especially with dynamic microphones ) is amplified to a level at which an amplifier or mixer can be controlled. The terms mic preamps ( as a necessary voltage amplifiers), and microphone " amplifier " ( as an impedance converter ) in the microphone body are not kept apart particularly clear in the hobby engineering.