I am sorry I connected the new 100uf capacitor to your synthesized ground when it was supposed to filter the battery voltage.
I have made many opamp circuits with a single-polarity supply but none used your synthesized ground.
They simply had the input of the opamp biased with a filtered half-the-supply-voltage then the circuit ground, input ground, output ground and all filter capcitors are connected to the negative terminal of the battery.
A little 9v battery has a fairly high internal resistance that increases as it is used so its voltage jumps up and down with the signal if it is not filtered. Also ALL opamps need a power supply filter capacitor to prevent oscillation.
I have made many opamp circuits with a single-polarity supply but none used your synthesized ground.
They simply had the input of the opamp biased with a filtered half-the-supply-voltage then the circuit ground, input ground, output ground and all filter capcitors are connected to the negative terminal of the battery.
A little 9v battery has a fairly high internal resistance that increases as it is used so its voltage jumps up and down with the signal if it is not filtered. Also ALL opamps need a power supply filter capacitor to prevent oscillation.