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question 1: the problem is : how to raise 30 % direct current (DC) gain in op-amp circuit ?
answer : try to change the resistor R4 value to 1K , Q10 multiplier to 15 times and change the Q8 value to 0.2
Question2 : Do we need to do something at R9 & R10 to improve it?
or depend on the Vcc? answer : no...