Audio Amplifiers
Dynamic mic preamplifier
This mic preamp uses the low noise IC uA739. The circuit is an example of how a good preamplifier can be designed for dynamic microphones. The IC houses two identical integrated preamp circuits. The second preamp is used in identical manner for the second channel of the stereo microphone.
Diagram bellow shows the pin numbers (in [...]
Low noise preamplifier
A preamplifier circuit with a very low noise characteristic can be built by simply combining a FET transistor with a bipolar one.
The input impedance of the preamp circuit is almost the same as the gate impedance of the FET transistor (around 1MΩ) The output impedance at the other end is about 1KΩ.
The frequency of this [...]
Audio amplifiers from class A to T
The final amplifier is the power source of every audio installation. Its job is to convert a small alternating voltage into a powerful signal for driving loudspeakers with as little distortion as possible.
Delivering a large amount of power is not a simple task for an amplifier. Voltage amplification and current amplification are both necessary in [...]
