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A Better Microphone Amplifier

A BETTER MICROPHONE AMPLIFIER#

like Blackpool only better

This circuit is an improvement, in many ways, to the other offering within the YooFab Circuit Snippets section. It is capable of handling many types of microphone, excluding ancient relics, such as carbon-resistive types. It's compatible with both dynamic and electret microphones. However, it draws more power than the other offering, but this is the price of the improvement and gain it offers. The quiescent current used here is approximately 15 milliamps at 12 volts.

The electret microphone is a variant of the electrostatic condenser microphone that uses a polarised plastic foil electrode (fluorocarbonate or fluorine polycarbonate) that does not require power.

THIS MICROPHONE AMPLIFIER CAN MAKE USE OF SIGNALS AS LOW AS ONE MILLIVOLT#

  • 1 mV produces: 31 mV output into any load above 120 ohms.
  • 20 mV produces: 579 mV into any load above 120 ohms.

The above characteristics make this amplifier ideal for supplying a balanced or double balanced radio frequency mixer. As such, and although it does not have roll off at the top end, nor at the bottom end, this microphone preamplifier is perfectly suitable for almost any radio application known to mankind.