Why does the Microphone Require an External Power Supply?

- Apr 30, 2019-

We know that condenser microphones require power for two main reasons: one is to polarize the capsule; the other is to drive the preamplifier (Note: the main role of the "preamplifier" here is only amplifying the weak voltage from the capsule into a microphone level is not what we usually call a "front microphone amplifier").

However, there are currently many microphones that are pre-polarized or electret capsules. In this case, the power supply is only used to drive the preamplifier circuit. As for most tube microphones that require an external power supply, the main reason is that the tube preamplifier requires a higher operating voltage than the 48 volts that the phantom power supply can provide. However, in recent years, there have been some tube microphones that do not require the use of an external power supply and rely solely on phantom power.

In addition to tube microphones, some solid-state microphones also require an external power supply because the preamplifier used requires a higher operating voltage than 48 volts.

Due to the increase of the voltage, not only the dynamic range of the microphone is greatly expanded, but also the ability of the microphone to handle the high sound pressure level can be effectively improved. Therefore, the microphone of the external power source can be used for materials with high dynamic range for classical music and the like. The advantages are especially noticeable when recording.

In addition to this, the advantage of using an external power supply is that it can help many low-end consoles to get rid of the phantom power supply that can be used when recording multiple preamps at the same time, especially when recording sound sources with high sound pressure levels. Insufficient embarrassing situation.



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