I am using the headphone output on the WM8731 codec for line out or optionally headphone out. I want to detect the difference between a mono 1/4” plug (line out) and a stereo (headphone out) when the connector is plugged in. If I ride a DC level on the AC headphone output, it is hard to detect the difference between a shorted ring to shield (mono plug) and a 16 ohm headphone. Any suggestions?