There's a trap for young players (as Dave from the EEVBlog likes to say). In the circuit I posted: The 2M2 feedback resistor for the DC servo poses to high an impedance at the inverting input of the servo opamp if you use a bipolar input one. The input bias current will cause too much voltage drop in the feedback R. Either lower the feedback R and increase the servo C - or use a FET input opamp with an input bias current usually around three orders of magnitude lower.
Otherwise the circuit now works beautifully. Still have to measure actual CMRR though but simulation showed that everything's fine though.
Otherwise the circuit now works beautifully. Still have to measure actual CMRR though but simulation showed that everything's fine though.