What kind of capacitors should I use to couple audio? I'm dealing with line level 1Vp-p audio, with a 1V dc offset (typ.) I want to convert this into 1Vp-p AC, at up to 20 kHz. My first version used ceramic 10u 10V caps - a simulation showed attenuation by about 15% at 20 kHz.
Update: I eventually went for 10u 6.3V. I did not need Hi-Fi quality and the fact that 10u 6.3V caps were available in 0603 packages was useful for me.
Answer
When you are using capacitors to couple a circuit you need to be worrying about the low frequencies. A coupling capacitor is by definition a high pass circuit.
The larger the capacitor value you chose, the lower your cut off frequency will be on the high pass circuit. Wikipedia shows an example circuit as well as how to pick your capacitor value in respect to your desired cut off frequency and resistance.
As for the type of capacitor, since audio is AC you will need to have a non-polarized capacitor. In my experience, I have never found anything better then a ceramic capacitor for this application.
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