Audio Kits
Electret microphone amplifier circuit
This article describes an compact electret microphone amplifier but you can connect dynamic microphones with low resistance. Electret microphones can be inserted in the same box with the amplifier, it only need 5 to 10V or 9V battery with a current consumption of just 1.5mA.
Here you got the electret amplifier schematic:
4 channels mixer voltage controlled
The audio mixer schematic we propose is developed arround 4 amplifiers build inside SSM2024 produced by Precision Monolithics Inc. (PMI) and is voltage controlled (VR).
The maximum VR voltage is 5.5V. The signal/noise ratio is 90dB and 130Khz band wide. This 4 channels mixer works great at +- 15V but you can use voltages between 9V [...]
Automatic Gain Control - Volume AGC
The schematic we propose offers a less harmonic signal and a supplementary gain, so it get rid of those annoying variation between speech and music wich offen appears at radio and tv. This automatic gain volume control schematic need a +-15V power supply and 6mA.
Bellow you get the volume agc circuit pcb, graphic and [...]
