Your schematic has a power supply that is "HI and LO" but shows no voltages. Since the input voltage reference of the first opamp at its pin 3 is 0V through R15 then the opamp needs a positive supply and a negative supply.
If its pin 3 was biased at half the supply voltage then a single-polarity power supply can be used.
Without R14 its voltage gain will be 1+ (270K/10k)= 28.
R1 should be removed since it reduces the input level.
If its pin 3 was biased at half the supply voltage then a single-polarity power supply can be used.
Without R14 its voltage gain will be 1+ (270K/10k)= 28.
R1 should be removed since it reduces the input level.