Preamp Circuit | Electronic Project Circuits

Posts Tagged ‘preamp circuit’

Dynamic Microphone Preamp

Circuit : Andy Collinson
Email: anc@mitedu.freeserve.co.uk

Description:
A low noise pre-amplifier suitable for amplifying dynamic microphones with 200 to 600 ohm output impedance.

Notes:
This is a 3 stage discrete amplifier with gain control. Alternative transistors such as BC109C, BC548, BC549, BC549C may be used with little change in performance. The first stage built around Q1 operates in common base configuration. This is unusuable in audio stages, but in this case, it allows Q1 to operate at low noise levels and improves overall signal to noise ratio. Q2 and Q3 form a direct coupled amplifier, similar to my earlier mic preamp.

Source: http://www.mitedu.freeserve.co.uk/Circuits/Audio/dyn_mic/dyn_mic.htm