You have 4.7k for R34 when it is supposed to be 4.7 ohms.
Your circuit has a few audio attenuators:
1) R135 into the very low input impedance of R137, R138 and Q39 reduce the detected signal by about 1/23.
2) R100 and R38 attenuate the audio signal by 1/11.
3) R147 and the input of Q42 attenuate the audio by about 1/11.
So the total attenuation is almost 1/3000 times.
Your circuit has audio gain coming out of its ears. No wonder it oscillates:
1) Q39 has a voltage gain of about 150 if C43 is connected to ground.
2) Q42 has a voltage gain of about 100.
3) The 741 opamp has a voltage gain of 22.
4) Q19 has a voltage gain of 83.
5) The TDA2822 has a voltage gain of 100.
The total audio gain is 2,740,000,000 which is rediculous.
Your volume control is not a voltage divider.
The feedback from the power supply is injected into the audio by all the bias resistors for the transistors and by R151.
I was wondering what is Q40 and Q41??? They make a darlington (drawn oddly) but it is not needed.
Your circuit has a few audio attenuators:
1) R135 into the very low input impedance of R137, R138 and Q39 reduce the detected signal by about 1/23.
2) R100 and R38 attenuate the audio signal by 1/11.
3) R147 and the input of Q42 attenuate the audio by about 1/11.
So the total attenuation is almost 1/3000 times.
Your circuit has audio gain coming out of its ears. No wonder it oscillates:
1) Q39 has a voltage gain of about 150 if C43 is connected to ground.
2) Q42 has a voltage gain of about 100.
3) The 741 opamp has a voltage gain of 22.
4) Q19 has a voltage gain of 83.
5) The TDA2822 has a voltage gain of 100.
The total audio gain is 2,740,000,000 which is rediculous.
Your volume control is not a voltage divider.
The feedback from the power supply is injected into the audio by all the bias resistors for the transistors and by R151.
I was wondering what is Q40 and Q41??? They make a darlington (drawn oddly) but it is not needed.