Grumpy_Mike:
Don't try and build a non-inverting amp, go for an inverting amp,
For audio it makes not a jot of difference.
Yes, I understand and I've no specific need for a non inverting amp, I was just trying to understand if I was misunderstanding the amp circuit. Inverting or non inverting doesn't make difference for my application.
Grumpy_Mike:
@rlogiacco
The biasing on the output was fine. It was the input that was not. See the attached diagram, the first one you get when googling.
I'll do my best to understand it XD
Grumpy_Mike:
There is no need for the pot. The -ve end of the 10uF cap should go to the analogue input of the arduino. With a 10K resistor to +5V and another to ground to complete the biasing for the analogue input.
The gain is the ratio of the 100K and 1K resistors going to pin 2 of the op amp. So this is a simple X100 gain. Adjust these values for other gains.
The pot was there to control the gain as I think I need such control at this stage when I don't have any clue regarding the real gain I'm looking for.
With regards to connecting the Arduino analog pin to that point, wouldn't I risk to input a voltage higher than 5V and consequently damage the pin? I thought the voltage divider I created on the Arduino side would have ensured isolation and protection to the arduino...