The 100kOhm resistors are lost somewhere. But there are 220 kOhms available. Would it be OK to come here instead of 100K?
I would think so. They just provide that all important ground reference and there is also no noise penalty because at AC that resistor is shunted by the output impedance of whatever you connect to the input.
You only need just one resistor at the input, either the 100k or 220k. Whichever you prefer. If it were me and as I mentioned before I would link out R3 and C3 with that new opamp fitted. Also keeping the input AC coupled is recommended.
OK. Thank you so much for the tips, hints and patience! I would like to express my gratitude to Mooly and other participants who did not ignore this topic. I wish you all peace and goodness!!! The topic can be closed. Sincerely, kumiroff.
