Thanks for your suggestion.
I have check the resistor values around the DAC and the OPAMP and nothing odd at all.
I had order IRF9Z24NPBF and IRL520NPBF at element14 but it turn out IRL520NPBF out of stock and I have source it again from china seller.
When I purchase IRL520NPBF, I also purchase the IRF9Z24NPBF as well but I suspect I got inferior counterfeit. I checked them both with component tester. IRF9Z24NPBF VT=2.0V C=685pf |AND|
IRL520NPBF VT= 1.8V C=1.83nF
I using the 42TU200 transformers as same as you. I don’t want to have too many wires flying around and I connect 3 wire only (Have not connect the Transformer P side because I think the output side is direct connect to 3.5 output jack only and AVR will know nothing regarding the final output.
The 1/2 watt 0R5 is good. I check it value with LCR meter.
I google the IRF9Z24NPBF and IRL520NPBF image and try to located what the genuine chips exactly look like. I found tons of different image, beyond 10+ different outlook. That’s horrible, I have no idea which one is genuine now.
Please do me a favor and share the image of working IRF9Z24NPBF and IRL520NPBF. I want to know how the working one look like. Please also check them with component tester and let me know all the measurement value you got from the tester.