Mic Compressor using 3 Transistors is a simple, yet effective, compressor circuit that can be used to improve the dynamic range of a microphone signal. The circuit is made up of three transistors, and it is powered by a 12-volt supply. It was designed by Eko Pramono, a ham radio operator from Indonesia. The circuit is based on the principle of feedback, where the output signal is fed back to the input of the first transistor. This creates a negative feedback loop that reduces the gain of the circuit when the input signal level increases.
Here is a brief overview of the circuit:
- The first transistor (Q1) is a preamplifier. It amplifies the input signal and provides a gain of about 20.
- The second transistor (Q2) is a buffer. It isolates the first transistor from the third transistor and prevents the feedback loop from becoming unstable.
- The third transistor (Q3) is the compressor. It provides the negative feedback that controls the gain of the circuit.
- Q1,Q2 &Q3 are 2N2222 or BC548
The negative feedback signal from the third transistor reduces the gain of the first transistor as the signal level increases. This is what provides the compression effect. The amount of compression is determined by the values of the resistors in the feedback circuit. The higher the values of the resistors, the more compression will be applied.
The circuit works by reducing the gain of the amplifier as the input signal level increases. This has the effect of making the louder parts of the signal quieter, while leaving the quieter parts of the signal unaffected. This can be used to improve the dynamic range of a signal, making it sound more balanced and even.