In my current project setup I generate audio signals from my MCU's internal DAC. These audio signals are transferred to a speaker box with an internal amplifier via phone jack. To make the whole project more portable, I thought about giving my \$8\Omega/0.25W\$ speaker a try. Since the DAC should not output too much current I decided to add a class A audio amplifier with voltage divider biasing to the DAC's output.
The result would look something like this:
Now my problem is that the DAC's output is always positive (between \$0.2V\$ and \$3.1V\$). Because C3 is an AC coupling capacitor, it will feed current back into the DAC when the audio signal becomes negative. Will this damage the MCU? And at which voltage level should I bias Q1?
By the way, the MCU I'm using is the STM32H743ZI.