In an opamp circuit for audio purposes like the following, I'd like to know some informations about the capacitor C1:
- which type is the best in this application (polyester, Al electrolytic, tantalum, bi-polar electrolytic);
- if polarized, what is the correct polarity in the circuit and why.
The choice of electrolytic capacitor is giustified because it needs a large value if you want to keep a good lower cutoff frequency (in the example, about 70Hz) and low resistor values to reduce noise; but I'd like to know if there are troubles with the polarization (and maybe the distortion due to non-ideality)
Moreover, is it correct that C1 reduces op-amp offset effects at the output?