I use analog5 pin for audio input in Arduino Uno. The no signal bias is set to 2.5volts (around 520 ADC value) Everything works fine without the VMA202 shield but if I plug the shield on the Arduino and use the analog5 pin of the shield, the no signal level shifts to around 4.9 volts (around 1000 ADC value) No way to get it back to 2.5 volts. Anyone knows what happens?
There is a fault somewhere in the shield. Do not know if it is by design or by manifacturing but the A5 analog in is not completely isolated from the ground, measuring gave some ohms between the two. So i just clipped the a5 pin of the shield, connected the audio input straight to the a5 analog in of the Arduino and everything was fine.