Whenever I use the 3.5 mm audio jacket I get a lot of background noise even when I'm not playing any sounds. Can I fix this by buying the analog audio extentsion board or is there a simpler (and cheaper) solution?
Well, one person reported that pushing the 3.5mm plug in all the way cured it for him... Certainly a cheap solution!
You didn't mention what version of the Pi and how you are powering it. Are you feeding headphones or an audio amp?
If it's an audio amp, how is it powered?
You are in a maze of twisty little passages, all alike.
When General Failure and Major Disaster get together, Private Parts usually suffers.