Introduction: Class AB Amplifier

By

Hi, I would like to share with you with my project of class AB amplifier. It can supply 70W RMS at 4 ohm impedance load per channel. Schematic and PCB have been created in KiCad.

Supplies

All components that I will post here. But first I need to test the setup.

Step 1: Description of Amplifier

At output stage I decided to use Sziklai pair. Q6 is typical voltage biasing between output transistors, Q31,Q19,Q25,Q26,Q3,Q2 are working as current source. Q5,Q24 are to take signal from differential pair. Q1 and Q4 have to be paired up. All components in the feedback loop are important because the amplifier can start oscillating. I am not quite sure about all value of components. I need to test on real setup. The supply voltage is +/-24VDC. If you need calculation or any information of components for this project you can send me a message, I won't upload it because I think it is not a point of this project. Input signal came from AUX, volume is regulating by potentiometer. Yes I know I have to add radiator for output stage. Q6 has to be on the same radiator, it is connected with thermal compensation of transistor.

Step 2: Photos of Real Amplifier

Soon... After I get my PCB and test it.