Ipod audio output through an opamp (LM358N)

[boylesg]

Previous attempts to do this have failed to work properly and I am wondering if an impedance mismatch is causing this.

The impedance of the ipod ear buds is about 32R but the input impedance of the opamp is something like 1M.

Would this be causing the problems of not getting reliable audio out put from the opamp?

Would I get better results if I passed the ipod output through a unity gain or x2 gain common emitter amplifier with an input impedance of 40R and an output impedance of 1M, and then feed the output of this into the opamp input?

I am trying to boost the ipod output signal to about 6-8V peak.

On its own the output peak voltage of the ipod seems to be less than 1V.

 

[FvM]

I fear, anyone reviewing your previously thread https://www.edaboard.com/threads/275869/ will be left helpless. He doesn't see an exact schematic troughout the pretty long discussion. Most likely he'll agree with the majority view that the stripboard setup has hidden faults.

But one thing is sure, though. It's definitely not an input impedance matching problem.

 

[boylesg]

The problem is that I have soldered the circuit 3 times, with components space apart to avoid stray solder blobs, with the same result.

I find it difficult to believe I have made the same inadvertent mistake 3 times in a row.

There must be some other issue that I am not aware of with these circuits. If not an impedance mismatch issue then something else but I have not been able to find through googling.