The UA741 does not have good -Rail Power Supply Rejection.
Use a different opamp.
Notice location of the 25pF capacitor. The right end is the large-voltage-gain node for the opamp. The left end is two diode drops (Q16,Q17) above the negative rail.
At high frequencies (fast trash on the -VDD rail), the trash on the -rail is copied onto the VOUT (base of Q18) and then heavily buffered to the output pin.
The UA741 does not have good -Rail Power Supply Rejection.
Use a different opamp.
The UA741 does not have good -Rail Power Supply Rejection.
Use a different opamp.
Notice location of the 25pF capacitor. The right end is the large-voltage-gain node for the opamp. The left end is two diode drops (Q16,Q17) above the negative rail.
At high frequencies (fast trash on the -VDD rail), the trash on the -rail is copied onto the VOUT (base of Q18) and then heavily buffered to the output pin.
