Originally Posted by DUG
OP2 has a gain of 11 and OP1 has a gain of -10.
To fix this add a 4K7 in series with C10.
The LR in the output path helps isolate capacitive loads from the amp.
"...change R5 to a 100K pot to trim output DC."
Vos on that device can be as much as 15mV. (one each way is 30mV)
If you add to that an imbalance of resistance to the inputs the input current could give you more offset between the two amplifiers.
With the adjustment you could trim that to a very low value.
After you build it (without speaker) adjust the pot and measure the output VDC.
If you don't need it, take it out.
If you don't want to put it in then make it 47K like the other ones.
Totally understood.Thank a lot.
Even with mismatched gains (11 & -10) I can run the system